Posts Tagged ‘pest management’

Sweet Corn IPM Newsletter No. 2 – July 8, 2013

Tuesday, July 9th, 2013

Sweet Corn

Sweet Corn IPM Newsletter No. 2 – July 8, 2013

For full page print version, please see link at the bottom. Click on photos to enlarge.

EUROPEAN CORN BORER, CORN EARWORM MOTHS ACTIVE

Silking Corn Needs Protection in Early Fields

SITUATION
Warm conditions and lots more rain have kept corn growing, but made it difficult to do any field work, such as spraying or side-dressing. Early fields in some areas are showing silk, and later fields, although uneven, are coming into pre-tassel. Some growers have had difficulty getting onto wet ground to seed their last plantings. The rain also is raising concerns about fertilizer and herbicide leaching.

European corn borer:  Moth catches were irregular this week with about half of the sites having any moths caught, and just a few over threshold for early fields with silking corn. Activity may increase over the next week, as the wet weather might extend the emergence of this first generation of moths. European corn borer feeding damage was over threshold in pre-tassel fields in Biddeford, Cape Elizabeth, Livermore Falls, and Nobleboro this week. One field (No. Berwick) that had both silking corn and was over threshold for moths was also put on a spray program for corn earworm, so no additional sprays were required.

European Corn Borer Damage

European Corn Borer Damage, photo by David Handley

Corn Earworm Moth

Corn Earworm Moth, photo by David Handley

Corn earworm:  About one half of the fields visited this week had corn earworm moths in pheromone traps. Most of these fields do not yet have any silking corn, so no sprays were recommended. When more than one corn earworm moth is found at a site, all silking corn in the fields should be protected with a spray. Additional sprays are based on the average number of moths caught per week or per night (see table below). Silking fields in Dayton, No. Berwick and Wells were recommended to go on a 6-day spray program for silking corn this week, based on a weekly capture of 3 moths.

Male Fall Armyworm Moth

Male Fall Armyworm Moth, photo by David Handley

Fall armyworm:  We have caught a couple of fall armyworm moths in pheromone traps this week, although the identification has not been confirmed. We have not yet seen any feeding damage from this pest, so no sprays for fall armyworm have been recommended.

Squash vine borer moths are being caught in pheromone traps in southern Maine. The moths lay their eggs at the base of squash or pumpkin plants, and the larvae tunnel into the vines, causing them to wilt and collapse. Entry holes can often be found near the base of the plant.  Sprays can be applied to control the moths and prevent egg-laying. Plow down squash plantings as soon as harvest is complete to prevent borers from overwintering in the field. There is one generation per year. See the New England Vegetable Management Guide for more details.

Japanese beetles are becoming plentiful in southern and mid-state areas. These insects often find their way into corn fields and may feed on the silks of developing ears, causing poor tip fill. Sprays for corn earworm (except Bt’s) will often control Japanese beetle as well.

Japanese Beetle

Japanese Beetle, photo by Edwin Remsberg, USDA

Male and Female Spotted Wing Drosophila Flies

Male (left) and Female (right) Spotted Wing Drosophila, photo by Griffin Dill. Actual size: 2-3 mm.

Spotted wing drosophila:  We have had our first captures of spotted wing drosophila in New Hampshire and Maine this week. These small fruit flies can cause serious fruit losses in raspberries, blueberries and other soft fruits. The flies will only attack fruit that has begun to ripen, and we don’t expect populations to reach damaging levels for a few weeks. For more information visit the Highmoor Farm website.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

Highmoor Farm                       Pest Management Office
P.O. Box 179                             491 College Avenue
Monmouth, ME  04259        Orono, ME  04473
207.933.2100                          1.800.287.0279

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Auburn 0 7 0 8% No spray recommended (no silking corn)
Biddeford 0 2 0 42% One spray recommended for ECB on pre-tassel corn
Cape Elizabeth I 0 0 0 3% No spray recommended
Cape Elizabeth II 6 12 1 20% One spray recommended for ECB on pre-tassel corn
Dayton 3 1 1% 6-day spray interval recommended on all silking corn
Farmington 2 1 0 2% No spray recommended
Lewiston 0 0 0 0% No spray recommended
Livermore Falls 1 0 0 28% One spray recommended for ECB on pre-tassel corn
New Gloucester 0 0 1 0% No spray recommended
Nobleboro 2 11 0 18% No spray recommended (no silking corn)
No. Berwick 3 13 0 6-day spray interval recommended on all silking corn
Oxford 1 1 0 6% No spray recommended (no silking corn)
Warren 0 0 0 4% No spray recommended
Wells I 2 0 0 0% No spray recommended (no silking corn)
Wells II 3 4 0 4% 6-day spray interval recommended on all silking corn

CEW: Corn earworm (Only fresh silking corn should be sprayed for this insect.)
ECB: European corn borer
FAW: Fall armyworm

Corn Earworm Spray Thresholds for Pheromone Traps

Moths caught per week Moths caught per night Spray interval
0.0 to 1.4 0.0 to 0.2 No spray
1.5 to 3.5 0.3 to 0.5 Spray every 6 days
3.6 to 7.0 0.6 to 1.0 Spray every 5 days
7.1 to 91 1.1 to 13.0 Spray every 4 days
More than 91 More than 13 Spray every 3 days

Thresholds apply only to corn with exposed fresh silk. Lengthen spray intervals by one day if maximum daily temperature is less than 80°F.

European Corn Borer Thresholds
Whorl stage:  30% or more of plants scouted show injury.
Pre-tassel-silk:  15% or more of plants scouted show injury.
Silk:  5 or more moths caught in pheromone traps in one week.

IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/

Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.

Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the State of Maine and the U.S. Department of Agriculture cooperating.  Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.

Sweet Corn IPM Newsletter No. 1 – June 27, 2013

Friday, June 28th, 2013

Sweet Corn

Sweet Corn IPM Newsletter No. 1 – June 27, 2013

For full page print version, please see link at the bottom. Click on photos to enlarge.

2013 SWEET CORN PEST SEASON BEGINS!

Corn Earworm, European Corn Borer Moths Active, Larvae Feeding in Early Corn

The 2013 University of Maine Cooperative Extension Integrated Pest Management (IPM) program for sweet corn is underway. More than twenty volunteer farms are serving as pest monitoring and demonstration sites, with fields in North Berwick, Wells, Dayton, Cape Elizabeth, New Gloucester, Poland Spring, Auburn, Lewiston, Sabattus, Nobleboro, Warren, Monmouth, Wales, Wayne, Oxford, Farmington, Levant, Stillwater, Garland and East Corinth. Pheromone traps have been set up at these farms to monitor the adult (moth) stages of European corn borer, corn earworm and fall armyworm, and we have begun scouting the fields for feeding injury by insect larvae. We will share the information we collected at these sites and management recommendations every week during the season through this newsletter and blog. If you would prefer to receive this newsletter via e-mail, give us a call at 207.933.2100 or send an e-mail message to: pamela.stpeter@.maine.edu.

David Handley Checking Harstack Trap for Corn Earworm Moth

Checking Harstack Trap for Corn Earworm Moth, photo by Edwin Remsberg, USDA

SITUATION
A spell of warm, dry conditions in late April and early May allowed farmers to begin planting corn early through plastic mulch or under row covers. Some of this corn is now in the tassel stage, with a few fields showing some early silk. However, the more recent cool, damp conditions have kept development of later plantings very slow, varying from just a few leaves to early whorl stage. Both European corn borer and corn earworm moths are active in some fields, but their impact is limited if corn is not yet silking.

European Corn Borer Moth

European Corn Borer Moth, photo by David Handley

European corn borer:  We are just starting to find European corn borer moths in the pheromone traps around the state, and activity will likely increase over the next two weeks. These moths are now laying eggs on the undersides of corn leaves. The egg masses are small and look like overlapping fish scales. European corn borer is the only one of the three major insect pests of corn that can successfully overwinter in Maine, and it is usually the first pest to become a significant problem. To monitor corn borer, we scout 100 corn plants in each field, examining twenty plants in a row at five different locations. This sample provides a good estimate of the total amount of injury in a field. In the early stages, European corn borer feeding damage looks like small “pinholes” in the leaves. Corn in the whorl stage only needs to be sprayed if fresh feeding injury is found on 30% or more of the plants scouted in a field. Once the corn reaches the pre-tassel stage, the control threshold is lowered to 15%. This is because larvae feeding on the later stages are more likely to move into the ears of the plant. On the tassels, feeding damage first appears as chewing and brown waste found in the small florets. After the tassel has emerged from the stalk, the larvae chew into the stalk just below it, often causing the tassel to fall over. Sprays during the pre-tassel stage, when both moths and larvae are present, reduce the opportunity for larvae to move into the stalks and ears of the plant. Once the larvae are in the stalks they are protected from sprays.

European Corn Borer Damage on Pre-tassel Stage corn

European Corn Borer Damage on Pre-tassel, photo by David Handley

Good spray coverage of the entire plant provides the most effective kill of larvae as they move from one part of the plant to another. Rotating the type of insecticide used also improves control. Materials registered for controlling European corn borer include Bacillus thuringiensis products (XenTari®, Dipel DF®), Avaunt®, Coragen®, Warrior®, Lannate®, Baythroid®, Asana®, Radiant®, Delta Gold®, Mustang®, Sevin XLR® and Larvin®. When corn reaches the silk stage, sprays may be based on the number of corn borer moths caught in pheromone traps rather than feeding injury. European corn borer moths will lay eggs on flag leaves of silking corn and the larvae can move into the ears without leaving visible feeding injury that would be noticed when scouting. Therefore, if more than five moths are caught during a week in a field with silking corn, a spray will be recommended. Varieties of corn genetically modified to produce the Bt toxin (e.g. Bt corn, Attribute® varieties), should not need to be sprayed to control European corn borer. European corn borer feeding damage has been increasing in recent days and fields in No. Berwick, Sabattus and Livermore Falls were over the damage threshold in pre-tassel fields. Expect more injury to be showing up as more eggs begin to hatch. Early silking fields in Nobleboro and Warren were over the threshold for European corn borer moths caught in pheromone traps and sprays for those fields were recommended.

Corn Earworm Moth

Corn Earworm Moth, photo by David Handley

Corn earworm:  Pheromone traps are now set up around the state to monitor the arrival of corn earworm. Corn earworm generally appears in Maine in early July, but the actual date varies greatly. The arrival of this pest is only a concern for fields with corn in the silk stage. Fields not yet in silk do not need to be protected from corn earworm. When corn earworm moths start being caught at a site, all silking corn in the fields should be protected with a spray. These moths lay eggs on the fresh silks and the larvae move directly into the ears of corn. When corn earworm moths cannot find silking corn to deposit their eggs on, they may lay eggs on the leaves of younger corn. The larvae will feed on the foliage and tassels, similar to armyworm, until the ears become available. When larvae are found feeding on younger corn, the damage is accounted for, along with any borer or armyworm damage, to determine if a spray is warranted. We have caught a few corn earworm moths in a few southern and coastal locations this week. Only two fields are showing silk now and single moth catches do not warrant a spray.

Fall Armyworm Moths

Fall Armyworm Moths (female right, male left), photo by James Dill

Fall armyworm:  This is usually the last serious corn insect pest to arrive in Maine. The moths must fly in from southern over-wintering sites, and tend to lay their eggs on the youngest corn available. When the larvae hatch, they chew large, ragged holes in the leaves, and may bore into developing ears. Larvae may also move into the ears through the silk channel, behaving similarly to corn earworm. Pheromone trap catches will indicate if there is a threat to silking corn. However, corn will usually be on a spray program for corn earworm when fall armyworm is present, and both insects would be controlled.

Common stalk borer:  This pest can be a problem early in the season, but usually only around the edges of fields. The injury is similar to European corn borer, but the feeding holes are larger, with four or five holes running across the width of a leaf. The larvae are purple colored with white stripes. If high numbers of stalk borer are found in pre-tassel stage corn within the field (not just along the edges), include the injury with corn borer to determine if control is needed. Injury found in whorl stage corn is not a concern because the larvae will leave the plant before ears emerge.

Common Stalk Borer Damage

Common Stalk Borer Damage, photo by David Handley

Do-It-Yourself IPM:  To get the most accurate information about the pest situation on your farm you should monitor the fields yourself on a regular basis. Pheromone traps and lures are available that can give you an accurate, early warning of the arrival of all of the major insect pests. Traps and lures can be purchased from pest management supply companies such as Gempler’s (1.800.382.8473) or Great Lakes IPM (517.268.5693).

To learn more about IPM scouting techniques, insect identification and control thresholds, order the fact sheet Managing Insect Pests of Sweet Corn available from the University of Maine Cooperative Extension. Color pictures are provided to help with insect identification, and a chart with spray thresholds is supplied to post near your sprayer for easy reference. You can download a copy from the Pest Management website or call the Pest Management Office at 1.800.287.0279.

High Tunnel Tomatoes

High Tunnel Tomatoes, photo by Danielle Murray

Hold the Date!
Highmoor Farm Field Day and Summer Tour is on Wednesday, July 31, 2013 from 9:00 a.m. to 3:00 p.m. Registration fee is $20.00, including lunch, and preregistration is strongly encouraged. For more information, visit the Highmoor Farm website. Please contact Pam St. Peter at pamela.stpeter@maine.edu or 207.933.2100 to preregister.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

Highmoor Farm                       Pest Management Office
P.O. Box 179                             491 College Avenue
Monmouth, ME  04259        Orono, ME  04473
207.933.2100                          1.800.287.0279

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Auburn 1 25 No spray recommended (no silking corn)
Biddeford 0 5 0 10% No spray recommended (no silking corn)
Cape Elizabeth I 0 2 0 No spray recommended
Cape Elizabeth II 3 20 0 No spray recommended (no silking corn)
Dayton 1 0 0 0% No spray recommended (no silking corn)
Farmington 0 0 0 0% No spray recommended
Lewiston 0 0 0 0% No spray recommended
Livermore Falls 1 0 0 18% One spray recommended for ECB on pre-tassel corn
New Gloucester 0 1 0 0% No spray recommended
Nobleboro 0 26 0 2% One spray recommended for ECB on silking corn
No. Berwick 0 20 0 34% One spray recommended for ECB on pre-tassel corn
Oxford 0 4 0 No spray recommended (no silking corn)
Sabattus 0 33 0 19% One spray recommended for ECB on pre-tassel corn
Wales 0 0 0 0% No spray recommended
Warren 1 7 0 5% One spray recommended for ECB on silking corn
Wells I 0 2 0 0% No spray recommended
Wells II 0 0 0 0% No spray recommended

CEW: Corn earworm (Only fresh silking corn should be sprayed for this insect.)
ECB:  European corn borer
FAW: Fall armyworm

 

Corn Earworm Spray Thresholds for Pheromone Traps

Moths caught per week Moths caught per night Spray interval
0.0 to 1.4 0.0 to 0.2 No spray
1.5 to 3.5 0.3 to 0.5 Spray every 6 days
3.6 to 7.0 0.6 to 1.0 Spray every 5 days
7.1 to 91 1.1 to 13.0 Spray every 4 days
More than 91 More than 13 Spray every 3 days

Thresholds apply only to corn with exposed fresh silk. Lengthen spray intervals by one day if maximum daily temperature is less than 80°F.

European Corn Borer Thresholds
Whorl stage: 30% or more of plants scouted show injury.
Pre-tassel-silk: 15% or more of plants scouted show injury.
Silk: 5 or more moths caught in pheromone traps in one week.

IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/

Where brand names or company names are used it is for the reader’s information.  No endorsement is implied nor is any discrimination intended against other products with similar ingredients.  Always consult product labels for rates, application instructions and safety precautions.  Users of these products assume all associated risks.

Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the State of Maine and the U.S. Department of Agriculture cooperating.  Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.

Strawberry IPM Newsletter No. 6 – June 14, 2013

Friday, June 14th, 2013

Strawberries

Strawberry IPM Newsletter No. 6 – June 14, 2013

For full page print version, please see link at the bottom. Click on photos to enlarge.

STRAWBERRY HARVEST STARTS SLOW, BUT PROMISING

Wet, Cool Weather Slows Ripening, Elevates Fruit Rot Threat

Situation: Another cool, wet stretch of weather has slowed strawberry ripening this week. Southern growers are hoping to open for general picking this weekend, but may have to wait until next weekend in some fields, although many are now spot picking fruit for farm stands and farmers markets. The crop looks very good in most fields, despite the recent weather and early indications of winter injury and some frost damage.

Gray Mold on Strawberries

Gray Mold on Strawberries, photo by James Dill

Diseases:  Another round of rain this week has kept the potential for gray mold infections very high. For fields that are still in the early post-bloom stage it is important to keep young fruit protected with fungicides under wet conditions. If the last application was made prior to more than one inch of rainfall, an additional fungicide spray should be considered.

Anthracnose fruit rot has been reported in fields in Massachusetts, and will likely threaten fields in Maine as well, due to the recent rains and warmer temperatures. We recommend use of fungicide products that offer control of both gray mold and anthracnose, such as Pristine® or Cabrio®, as we approach harvest time.

Large Tarnished Plant Bug Nymph

Third Instar Tarnished Plant Bug Nymph, photo by David Handley

Tarnished plant bugs will continue to be a problem on later ripening fruit, although development of the nymphs appears to have been hindered by the recent weather. Continue scouting in late ripening fields that still have blossoms or small green fruit for plant bug nymphs and apply a recommended insecticide if the control threshold is exceeded. Pay close attention to pre-harvest intervals of pesticide products as fields begin to ripen. Products registered for control of tarnished plant bug include Assail®, Thionex®, Malathion®, Brigade®, Danitol® and PyGanic®.

Spittlebug

Spittlebug, Photo by David Handley

Spittlebug masses have been noticed in some fields this week. The spittle masses are usually found on the leaf stems just below the leaflets, and annoy pickers who get the spittle on their hands and arms during harvest. Spittlebugs tend to be a greater problem in weedy fields. Pesticides currently registered for spittlebug control include Provado®, Thionex®, Danitol® and Brigade®.

 

Spotted wing drosophila (Drosophila suzukii) is a new pest, introduced into Maine in 2011, which appears to have become established here. This insect may be a concern for late ripening strawberries, and will certainly pose a serious threat to day-neutral strawberries, fall raspberries and blueberries. This is a small “vinegar fly”, similar to those that hover around over ripe fruit in your kitchen. However, this species will lay its eggs on fruit before it ripens, so the fruit will be contaminated with small white maggots just as it is ready to pick. Infested fruit quickly rots and has no shelf life. This species can complete a generation in less than two weeks, with each female laying hundreds of eggs, so millions of flies can be present soon after just a few enter a field.  This makes them very difficult to control, and frequently repeated insecticide sprays (3 to 5 times per week) may be needed to prevent infestations once the insect is present. While the spotted winged drosophila can overwinter in Maine, it may not build up to damaging levels until late in the summer. This could mean that June bearing strawberries will not be threatened, but later ripening fruit such as day-neutral strawberries, raspberries and blueberries will need to be protected.

Male and Female Spotted Wing Drosophila Flies

Male (left) and Female (right) Spotted Wing Drosophila, photo by Griffin Dill. Actual size: 2-3 mm.

A single spotted wing drosophila was caught in a trap in Massachusetts this week. This is not cause for alarm (it’s actually later than the first capture last year), and no controls are being recommended at this time. But it does suggest that this insect will be growing more active in the coming weeks and that populations will start building thereafter. We will be setting out monitoring traps for spotted winged drosophila in fruit plantings around Maine over the next few weeks to gather as much information on it as we can, and determine how much of a threat this pest will pose this season. For more information on this new and important pest, visit Michigan State University’s Spotted Wing Drosophila website. There is a good fact sheet series on this pest available for free download on the Penn State website.

Review:  Keeping Strawberries Fresh for Market
If you‘re bringing fruit to market, make sure that it arrives in the best condition possible. Strawberries cool most efficiently if harvested early in the morning before they build up any field heat. Place fruit into refrigerated storage quickly and keep it out of direct sunlight. Fruit should be stored at 32°F and 95% relative humidity. Cold air should be moved through the boxes or flats of fruit with a circulating fan and/or exhaust fan to cool most efficiently. Temperatures lower than 32°F may freeze the fruit and ruin its fresh quality. A small, well-insulated building cooled with air conditioners and fans can provide effective temporary storage for strawberries. If you don’t have refrigeration facilities, keep the fruit as cool as possible by harvesting when air temperatures are cool, and keeping it out of direct sunlight. Transport the fruit to market as quickly as possible, and harvest only what you think you can sell in a day.

Girl with Quarts of Strawberries

 

Annual Pre-Harvest Checklist for Pick-Your-Own
It’s that time again! As harvest approaches, we like to remind you to take a moment and make sure that your farm is prepared to give your customers an enjoyable experience. Take our annual review below to evaluate your customer readiness. 

√      Signs to the farm are neat and easy to read.

√      There is easy access to the fields and plenty of parking.

√      Someone is ready to greet customers and offer parking instructions and directions to the field.

√      Access to the field is free of hazards.

√      Transportation is provided for the elderly and disabled.

√      The rules regarding picking are clearly posted.

√      Someone is in the field to show customers where to pick and to answer questions.

√      There are plenty of picking containers available.

√      Clean restroom and hand washing facilities are available.

√      Someone is available to help customers carry fruit out of the field.

√      The checkouts are fast and efficient.

√      Beverages are available.

√      Shade and seats are available for customers wanting to rest.

√      The help are friendly and knowledgeable.

A friendly, clean, and organized atmosphere will leave a lasting impression on your customers, encouraging them to come back and to recommend your farm to their friends.

Hold the Date:  Highmoor Farm Fruit and Vegetable Growers Field Day July 31, 2013
For more information visit the Highmoor Farm webpage.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

Highmoor Farm                       Pest Management
P.O. Box 179                             491 College Avenue
Monmouth, ME  04259       Orono, ME  04473
207.933.2100                          1.800.287.0279

Maine Cooperative Extension, the Land Grant University of the state of Maine and the U.S. Department of Agriculture Cooperating.  Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.  A Member of the University of Maine System.

Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.

Strawberry IPM Newsletter No. 5 – June 7, 2013

Friday, June 7th, 2013

Strawberries

Strawberry IPM Newsletter No. 5 – June 7, 2013

For full page print version, please see link at the bottom. Click on photos to enlarge.

STRAWBERRY HARVEST BEGINS IN SOUTHERN MAINE

Tarnished Plant Bug Activity High in Some Fields this Week

Situation:  A stretch of fair weather has moved strawberry development along at a more normal pace over the past few days. The heat and storms of last weekend do not appear to have caused any serious issues in strawberry fields we visited. Leaf spot and tarnished plant bugs were the most common problems seen. Harvest is getting underway in some fields that were under row covers this spring. Most fields are now beyond full bloom and most growers are predicting a “normal” opening date for their pick-your-own fields. Overall, most fields appeared very good this week and the crop looks quite promising.

Diseases:  The risk of gray mold infection remains very high, with significant rainfall predicted over the next few days. It is important to keep blossoms and fruit protected with fungicides under wet conditions. If the last application occurred over a week ago, or more than one inch of rain has fallen since the last application, an additional fungicide spray should be considered.

Anthracnose fruit rot also remains a threat as tropical storms often create the wet fields and high temperatures that are conducive to the development of this fruit rot. It may be best to use a fungicide product that offers control of both gray mold and anthracnose, such as Pristine® or Cabrio®.

Leather rot (Phytopthora cactorum) could also appear in fields if standing water is prevalent for an extended time following heavy rains. Aliette®, Agri-Phos® or Phostrol® applied during fruit development can help prevent leather rot when the risk of this disease is high.

Powdery mildew is just starting to appear in some fields this week. This was encouraged by recent warmer weather. Leaves that are cupping upward are the most notable symptom for this fungus disease, and you may also see red streaking on leaf and flower stems. We anticipate that powdery mildew will become more prevalent soon, because it prefers warm, humid conditions. Fungicides for gray mold that also offer control of powdery mildew include Topsin-M® and Pristine®.

Leaf Spot on Strawberry Plant

Leaf Spot, photo by David Handley

Leaf spot/leaf blight infections were noticed in most fields we scouted this week. Leaf spot or leaf blight, caused by the fungus Phomopsis obscurans, was the most common problem. This disease usually appears on mature leaves as small purple or red spots with white or brown centers. Over time the spots may coalesce into a larger lesion, and give the leaf a burned appearance. The disease can spread onto the fruit stems and calyxes, giving them an unattractive reddish-brown discoloration. Leaf scorch is caused by a different fungus, and has been less common this spring. The spots are smaller and don’t have the white or brown centers. The spots often coalesce to turn the leaves purple and necrotic. Strawberry varieties vary greatly in their susceptibility to leaf spot and leaf scorch, with many having at least some resistance. However, under high disease pressure, many will show some symptoms. Fungicides registered for leaf spots include captan, Topsin-M®, Syllit®, Cabrio®, Rally® and Pristine®.

First Instar Tarnished Plant Bug Nymph

First Instar Tarnished Plant Bug Nymph, Photo by David Handley

Tarnished plant bug populations were significantly higher in many fields this week. Half of the fields we scouted were over the control threshold for plant bug nymphs and sprays were recommended. At this time we are finding mostly very small, green, first and second instar nymphs. They can be distinguished from similarly colored aphids because they are much more active, and will run rapidly when disturbed. The nymphs and adults are feeding on flowers and developing fruit and will cause the berries to have hard, seedy ends and other malformations. Products registered for control of tarnished plant bug include Assail®, Thionex®, Malathion®, Brigade®, Danitol® and PyGanic®.

Clipper on Strawberry

Clipper on Strawberry, photo by David Handley

Strawberry bud weevil or “clipper” injury has been noted in several fields this week and we found more live clippers than in any previous scouting trips this year. However, most of the injury was to lower order (late, small) flower buds, so the economic significance of the potential fruit loss is minimal, and no sprays were recommended. If your fields still have late varieties in early bloom, you should continue scouting for clipper and apply controls if significant damage is noted to the buds. Be aware the clippers will move on to raspberries and blackberries and clip off their buds, once the strawberries have come into bloom.

Two-spotted spider mites were found in most locations this week but, with the exception of one field, were well below the control threshold. The predicted wet weather will probably slow further spider mite development, at least temporarily; but we still anticipate that populations will rise when hotter, drier weather arrives.

Sap beetles have been found in two fields this week while scouting for tarnished plant bug. This is not cause for alarm yet, but growers should be aware that they are present and keep an eye out for damage as the berries start to ripen. The 1/8 inch long, dark brown beetles chew small holes in ripening fruit, similar to slug injury. They may be seen in the holes they’ve chewed into ripe fruit, but often drop to the ground when disturbed. The best management strategy for sap beetles is good sanitation. Keep the field free of overripe fruit by picking often and thoroughly. Insecticide sprays for this pest can be effective, but should be a last resort during the harvest period. Assail®, Brigade®, Dibrom® and PyGanic® are registered for control of sap beetles with pre-harvest intervals ranging from 12 to 24 hours. Read the product label carefully for this and other application instructions and restrictions.

Birds, specifically cedar waxwings, will soon be moving into fields to feed on ripening fruit. Waxwings often destroy many of the early ripening fruit, despite our best efforts to scare them off. Only by keeping a near constant presence in the field and eliminating roosting sites can you reduce the damage. Feeding is reduced once the fields start to be regularly harvested and customers are present.

Songbirds are protected by law and should not be killed. However, permits may be issued for killing birds by the U.S. Fish and Wildlife Service if they receive a recommendation for such a permit from the Maine Wildlife Services Office (part of the USDA Animal and Plant Health Inspection Service) in Augusta, along with an application from the grower. There is a $50 fee for the application, and it may take over a month for the permit to be processed. The permit is good for one year, so if you have problems this season, consider applying for a permit this winter, to give you the option to kill birds, if necessary, next season. The Wildlife Damage Office has recommendations for managing birds in crops, and some control options available through their office. For more information call the office in Augusta at 207.629.5181. The office is located in the Capital West Business Center at 79 Leighton Road in Augusta.

Hold the date:  Highmoor Farm Fruit and Vegetable Growers Field Day July 31, 2013.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

Highmoor Farm                        Pest Management
P.O. Box 179                              491 College Avenue
Monmouth, ME  04259         Orono, ME  04473
207.933.2100                           1.800.287.0279

Maine Cooperative Extension, the Land Grant University of the state of Maine and the U.S. Department of Agriculture Cooperating.  Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.  A Member of the University of Maine System.

Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.

 

Strawberry IPM Newsletter No. 4 – May 31, 2013

Friday, May 31st, 2013

Strawberries

Strawberry IPM Newsletter No. 4 – May 31, 2013

For full page print version, please see link at the bottom. Click on photos to enlarge.

WARMER TEMPS SPEED STRAWBERRY DEVELOPMENT

Higher Temps also Likely to Increase Insect and Mite Activity

Situation: Damp weather stretched through most of the week again, but now things are heating up fast, and the sudden change of temperature should hasten fruit ripening. High temperatures may also stress plants, especially those that experienced winter injury, grub feeding, or any other factor that compromised the plants’ ability to take up water. If plants appear to be wilting, dull colored or otherwise stressed, it may be necessary to irrigate if soils have become dry, to help stressed plants prosper through the high temperatures. Early varieties in southern Maine are now beyond full bloom, and are showing green fruit. Later varieties are mostly in bloom, and the bees have been active under the better weather conditions. Fields that were under row covers are starting to show a few ripe fruit and more will be ripening fast over the next few days. Insect activity remains pretty low for the time being, although we are starting to see an increase, which will be enhanced by the higher temperatures.

Gray Mold on Strawberries

Gray Mold on Strawberries, photo by James Dill

Diseases:  The prolonged damp conditions earlier in the week have kept the risk of gray mold infection very high. So, if it has been more than a week since the last fungicide application, or the field has received more than one inch of rain since the last application, it would be best to apply another fungicide spray.

Anthracnose fruit rot is favored by warm temperatures and wet field conditions, a combination many fields will see over the next few days; so consider using a fungicide that will offer control of both gray mold and anthracnose when making your next fungicide application, such as Pristine® or Cabrio®.

Leather rot (Phytopthora cactorum) may also be an issue in fields where standing water has been prevalent this spring. A spray of Aliette®, Agri-Phos® or Phostrol® applied during bloom and fruit development can help prevent leather rot where the risk of this disease is high.

Powdery mildew:  We have not yet seen any significant signs of powdery mildew, but we anticipate it may become more evident soon, because this fungus can proliferate rapidly under warm, humid conditions. Some fungicides sprays for gray mold can also offer good control of powdery mildew, including Topsin-M® and Pristine®

Slime mold:  I have had a report of slime mold from our friends in New Hampshire this week. Slime mold fungi can occur on strawberry plants and mulch when we get very wet, warm weather in the spring or fall. The mold appears as a creamy white or tan colored, jellylike mass growing out of the soil and up onto leaves and flower clusters or just on top of the mulch. The mass is amorphous and may have gray or black fruiting structures covering its surface. The mold dries out to a hard, crusty structure with powdery spores. Slime mold fungi are not parasitic to plants; they just climb them to improve the spread of their spores, but the masses can smother single leaves or fruits and be unsightly. Slime molds disappear when dry weather returns. They do not require any management.

Clipper Damage on Strawberry Plant

Clipped Flower Buds from Strawberry Clipper, photo by David Handley

Strawberry bud weevil or “clipper” is becoming more active as temperatures rise. However, some early blooming varieties have already developed beyond the point where clipper can do significant harm. Most fields had only very light clipper injury in later flowering varieties this week; none of the fields were over the action threshold. Late blooming fields should still be scouted for clipped buds.

Tarnished plant bugs remain fairly scarce this week. We have seen a few adults and some small nymphs in the fields we scouted, but none were over the action threshold. Expect activity to increase as things get drier and warmer.

 

Strawberry Mite Symptoms

Strawberry Mite Symptoms, photo by David Handley

Two-spotted spider mites were found in higher numbers this week, and distributed over a larger area, but all fields were below the action threshold. The extended cool, wet weather likely slowed spider mite development, but we should anticipate that populations will rise under the recent hotter, drier weather.

 

 

 

Spittlebug

Spittlebug, photo by David Handley

Spittlebugs:  Be on the lookout for spittlebug masses in your fields as we approach harvest time. Although we haven’t noted any in fields this week, they may start to appear soon. The frothy spittle masses are found on the leaf stems (petioles), just below the leaflets, usually showing up around bloom. Although spittlebugs don’t pose a significant threat to the plants, the frothy spittle masses create an annoyance for pickers. Spittlebugs overwinter as eggs and the nymphs emerge in late May. The spittle masses may be at the base of the plants, so spread the leaves and inspect the crowns, leaf bases, leaf stems, and flower stems looking for them. The small, yellow-orange nymphs will be under the spittle. If the average number of spittle masses is more than two per square foot, a treatment may be warranted. Spittlebugs tend to be a greater problem in weedy fields. Pesticides currently registered for spittlebug control include Provado®, Thionex®, Danitol® and Brigade®.

Slug on Strawberry

Slug on Strawberry, photo by James Dill

 

Slugs may be a problem in some fields this season. Moist conditions encourage the presence of these mollusks. Slugs usually feed at night, leaving large holes and tunnels in ripening fruit. Baits such as Deadline®  and Sluggo® offer some control of slugs, but should be used prior to fruit ripening. Pay close attention to label instructions and precautions. Baits should also be applied to the fields in mid-September if slugs have been a problem, to reduce egg-laying.

 

Highmoor Farm Fruit and Vegetable Growers Field Day July 31, 2013
Plans are well underway for the Highmoor Farm Field Day to be held on Wednesday, July 31. Growers will have an opportunity to tour the fruit and vegetable research plots at the farm, part of the Maine Agricultural and Forest Experiment Station, and hear Extension specialists and guest speakers discuss current research on apples and grapes. University of Maine leaders and state legislators will also be on hand to offer updates on programs and legislation effecting farming in Maine. Please join us for the program, farm tours and lunch. More information will be coming soon.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

Highmoor Farm                       Pest Management
P.O. Box 179                             491 College Ave
Monmouth, ME  04259       Orono, ME  04473
207.933.2100                          1.800.287.0279

Maine Cooperative Extension, the Land Grant University of the state of Maine and the U.S. Department of Agriculture Cooperating.  Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.  A Member of the University of Maine System.

Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.

Strawberry IPM Newsletter No. 3 – May 24, 2013

Friday, May 24th, 2013

Strawberries

Strawberry IPM Newsletter No. 3 – May 24, 2013

For full page print version, please see link at the bottom. Click on photos to enlarge.

COOL, WET WEATHER SLOWS STRAWBERRY DEVELOPMENT

Risk of Fruit Rot Diseases Increased

Situation: A very dry spring has quickly turned into a very wet spring for most farms, as nearly a week of cool, rainy weather has put more than two inches of water on the fields, and slowed plant growth significantly. Plant development has changed very little over the past week, with early varieties in southern Maine now moving into or just beyond full bloom, and later varieties coming into bloom. Fields that were under row covers have green fruit up to an inch in size. So ripe fruit should not be far off, if we see some warmer, sunnier weather soon. Insect activity has also been slowed by the weather, but these conditions create a high risk of fruit rot infections, and fields coming into bloom should be protected with fungicides when conditions permit. 

Wet Strawberry Field

Wet Strawberry Field, photo by David Handley

Diseases:  Bloom is the critical time to protect strawberries from developing gray mold caused by the Botrytis cinerea. The rain of the past few days has made conditions very conducive to fungal sporulation and flower infection. Two to three sprays of fungicide during bloom are often required to protect against gray mold. Fungicide choices for control of gray mold in strawberries include captan/Topsin M® tank mix, Elevate®, Captevate® (a pre-mix of captan and Elevate®), Switch®, Scala® and Pristine®.

Leather rot (Phytopthora cactorum) can be a problem when there is water standing in the fields during bloom and fruit development, especially if the fields were not mulched last fall and the plants are on bare, wet soil. Leather rot should be managed by growing strawberries in well-drained soil and applying straw mulch between the rows to prevent berries from touching the soil and to reduce soil splashing up onto the berries. Foliar sprays of Aliette®, Agri-Phos® or Phostrol® can be applied during bloom and fruit development to prevent leather rot when there is excessive moisture in the field, especially in fields with a history of this problem.

Anthracnose on Strawberry

Anthracnose on Strawberry, photo by North Carolina State University

Anthracnose fruit rot is a potential problem when fruit ripens in fields that are wet from irrigation or rain. This fungus disease is favored by warm, humid conditions and can spread rapidly during rains or when fields are irrigated with overhead sprinklers. In cool seasons, it may appear close to harvest or may not show up at all. Anthracnose fruit rot is identified by black sunken lesions with wet, orange (and sometimes gray) spore masses in them. The fungus can survive and multiply on leaves without visible symptoms, appearing suddenly as a fruit rot when the conditions are right. Fungicides such as Cabrio® and Abound® can provide good control of anthracnose.

Powdery Mildew

Powdery Mildew, photo by David Handley

Powdery mildew:  No severe symptoms of powdery mildew have been observed yet, but we’re starting to see some leaf cupping in fields, suggesting that this disease may become a problem when temperatures start to rise. Upward cupping of the leaves and reddish streaking or lesions on the leaf and flower stems are the most obvious symptoms of powdery mildew. White, powdery growth on the undersides of the leaves appears as the disease develops further.

Strawberry bud weevil or “clipper” is becoming active as flower buds emerge. I have found one field with clipper at levels over threshold this week, but most fields were showing very little, if any damage. Early blooming varieties may have developed beyond the point where clipper can do significant harm to buds, but later blooming fields should still be scouted for injury. Clipper is likely to become more active when conditions become a little drier and warmer.   

Tarnished Plant Bug Nymph on Strawberry Blossom

Tarnished Plant Bug Nymph on Strawberry Blossom, photo by David Handley

Tarnished plant bugs adults are few and far between this week, which is typical in this kind of weather, but I still have not found any nymphs in blooming fields. It is difficult to find nymphs on wet plants, so we may see activity increase considerably when things dry out. But for now, no fields have been over threshold.  

Cyclamen mites:  We continue to see symptoms of cyclamen mite in strawberry fields this week, including weak growth, crinkled leaves and yellow, pinkish or blackened discoloration. Sprays for these mites must be applied with lots of water to carry the material down into the crowns where the mites reside. Portal®, Thionex® and Kelthane® are registered for control.  

Cyclamen Mite Damage

Cyclamen Mite Damage, photo by David Handley

Two-spotted spider mites were not found over threshold in any fields this week. Cool, wet weather tends to significantly slow spider mite development in strawberry fields, but expect populations to rise as conditions become warmer and drier, and keep scouting.   

White grubs:  We have found white grubs in three different fields this week, most likely the larvae of Asiatic garden beetle or European chafer. These grubs have legs and a dark, swollen rear end. They are found in the soil around the roots of weak plants.   Admire Pro®  can be used to control white grubs and should be applied within two hours of irrigation or rainfall to get the chemical into the root zone. This product has a 14 day pre-harvest interval.  

Spring fertilizer for strawberries
Heavy nitrogen fertilizer applications are not recommended in the springtime because excess vegetative growth at this time will result in a dense leaf canopy that will cover flowers and fruit, and encourage gray mold and two spotted spider mites. In the matted row system, most of the nitrogen fertilizer should be applied following harvest to stimulate new leaf and runner growth. For established beds, only 10-20 pounds of actual nitrogen should be applied in the spring. Calcium nitrate [Ca(NO3)2, 15% N] is a recommended source of nitrogen at this time because it is readily available, not volatile, and also provides calcium, which can help with fruit development.  Boron is another nutrient which can help early spring growth, and is especially important in the pollination and fertilization process that helps determine fruit size and quality. However, excessive amounts of boron can be toxic to strawberry plants, so only one to two pounds of actual boron (B) is recommended per acre during the spring. This is often applied as a foliar spray in a material such as Solubor
® (20% B). While foliar sprays are often an inefficient way to get nutrients to the plants, they are helpful when trying to evenly distribute a small amount of material over a large area.

honey bee on flower

Honey bee on flower

What about pollination?
After a hard winter for bees and lots of rain during bloom, growers are concerned about good pollination in their strawberries. Cultivated strawberry flowers are self-fertile, meaning that they don’t require cross-pollination with other varieties like some other fruit crops, such as apples or blueberries. Some studies have shown that strawberries will produce a good crop in the absence of bees, with pollination being carried out by wind and small, native insects. Other studies have shown an increased fruit quality and size when bees help with pollination, so it is certainly good to have them working in the strawberry fields, but perhaps not essential for this particular crop.

2013-2014 New England Small Fruit Management Guides are available from the University of Maine Cooperative Extension at Highmoor Farm. This new, updated edition of the guide contains the latest information on management options for small fruit pests as well as cultural information. Cost of the guide is $10.00 plus $2.53 postage for a total of $12.53. To order a guide, please send your check made payable to UMaine Cooperative Extension mailed to: Highmoor Farm, P.O. Box 179, Monmouth, Maine 04259, atten. Pam St. Peter. For more information, contact Pam St. Peter at 933.2100 or pamela.stpeter@maine.edu.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

Highmoor Farm                       Pest Management
P.O. Box 179                             491 College Ave
Monmouth
, ME  04259       Orono, ME  04473
207.933.2100                          1.800.287.0279

Maine Cooperative Extension, the Land Grant University of the state of Maine and the U.S. Department of Agriculture Cooperating.  Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.  A Member of the University of Maine System.

Where brand names or company names are used it is for the reader’s information.  No endorsement is implied nor is any discrimination intended against other products with similar ingredients.  Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.

 

Strawberry IPM Newsletter No. 2 – May 17, 2013

Friday, May 17th, 2013

Strawberries

Strawberry IPM Newsletter No. 2 – May 17, 2013

For full page print version, please see link at the bottom. Click on photos to enlarge.

Sprayer Calibration Clinic on May 21, 2013 at 2:00 p.m.
Twilight Meeting on May 21, 2013 at 5:00 p.m.
Pikes Farm to You in Farmington, Maine

STRAWBERRY BLOOM UNDERWAY

Few Insect or Disease Problems, Winter Injury Widespread

Strawberry Frost Injury

Frost Injury to Flowers and Leaves, Photo By David Handley

Situation: A little rain last weekend provided some relief from this very dry spring for most fields.  Frost hit many fields over two to three nights early in the week, and some injury has been noted wherever irrigation wasn’t able to protect the blossoms.   Plants in southern Maine are now showing open primary (king) blossoms on early varieties, while in later varieties buds are still emerging from the crown.  Fields that were under row covers are in full bloom, or just beyond, suggesting that we could see some ripe fruit in just a couple of weeks, weather permitting.  I am still finding winter injury, especially in older fields, where straw and or snow cover was inadequate during the coldest part of the winter.  On the bright side, insect activity remains fairly low in all fields scouted this week, but it is important to keep scouting during the bud emergence through bloom stages, because this is when the plants are most susceptible to clipper and tarnished plant bug.  Bloom is also the most critical stage for preventing infestation by Botrytis spores, which cause gray mold.

Sprayer Calibration Clinic and Twilight Meeting
The University of Maine Cooperative Extension and the Maine Vegetable and Small Fruit Growers Association will hold a sprayer calibration clinic for airblast sprayers at David Pike’s Farm to You in Farmington on Tuesday, May 21 at 2:00 p.m. George Hamilton with the University of New Hampshire Cooperative Extension will demonstrate new tools for making sure your sprayer is delivering the correct rate of pesticides to your crops. Having a sprayer properly calibrated will improve the effectiveness of your sprays, and can save you money by reducing the amount of pesticide used and reducing crop losses due to pests. Participants will receive two pesticide applicator recertification credits. The calibration clinic will be followed at 5:00 p.m. by a tour of David Pike’s strawberry and vegetable fields. David has been a leader in innovative strawberry production techniques, including raised beds, plastic mulch, fertigation, fall cropping, and season extension. There will be some new low tunnel technology on display, as well as replant experiments and new varieties on trial. One pesticide applicator recertification will be awarded for the meeting. The location is 115 Mount View Road. (corner of Routes 2 & 4 and the Whittier Road) in Farmington, ME 04938. There will be signs posted. The farm phone number is 207.778.2187. Cost for the clinic is free and no registration is required. Hold the date!

Drip Irrigation Workshop
Wednesday, May 22, 2013, 3:00 p.m. to 6:00 p.m. at the Sherman Farm, 2679 East Conway Road, Center Conway, NH 03813. The farm phone number is 603.939.2412.

The purpose of this meeting is to review what drip irrigation options and strategies vegetable and fruit growers should be considering for the coming growing season.  Trevor Hardy, of Brookdale Fruit Farm and George Hamilton, UNH Cooperative Extension will present a hands-on demonstration on setting up a drip irrigation system and describe the various components of a system, including set ups for high tunnels.  Toro Irrigation Representative Bill Wolfram will also be present.  The meeting will begin at 3:00 p.m. and will run until around 6:00 p.m.

For more information contact:

Olivia Saunders, UNH Extension Field Specialist
603.447.3834, e-mail: olivia.saunders@unh.edu, OR

George Hamilton, UNH Extension Field Specialist,
603.641.6060, email: george.hamilton@unh.edu.

2013-2014 New England Small Fruit Management Guides are now available at Highmoor Farm. This new, updated edition of the guide contains the latest information on management options for small fruit pests as well as cultural information. Cost of the guide is $10.00 plus $2.53 postage for a total of $12.53. To order a guide, please send your check made payable to UMaine Cooperative Extension mailed to: Highmoor Farm, P.O. Box 179, Monmouth, Maine 04259, attention Pam St. Peter. For more information, contact Pam St. Peter at 933.2100 or pamela.stpeter@maine.edu.

Clipper Injury

Clipper Injury, Photo by David Handley

Strawberry bud weevil or “clipper” should now be coming active as flower buds emerge. We have not found clipper at levels over threshold in any fields scouted to date, but it is important to keep a sharp lookout for clipped buds now, especially along wooded borders of the field.  If the average number of clipped buds exceeds 1.2 per two feet of row, or if live clippers are being found, control measures are recommended.

First Instar Tarnished Plant Bug Nymph

First Instar Tarnished Plant Bug Nymph, photo by David Handley

Tarnished plant bug adults are being reported in apple orchards in southern Maine, but we have not yet found any nymphs in the strawberry fields we have scouted. Strawberries are preferred hosts at this time of year, so we should expect to start seeing both adults and nymphs soon. To scout for the nymphs shake 30 flower clusters (six clusters in five different locations) over a plate. If four or more of the clusters out of the 30 sampled have any nymphs, control measures should be taken. Be on the alert and scout your fields as soon as blossoms start to open.

Cyclamen mites:  We have found symptoms of cyclamen mites in several plantings this spring. Symptoms include weak growth, crinkled leaves and yellow, pinkish or blackened discoloration. Cyclamen mites are too small to be seen without magnification and reside in the crown of the strawberry plant feeding on the developing leaves and flower buds. Miticides must be applied in lots of water to be sure that the material is carried down into the crowns where the mites reside.

Two-spotted Spider Mites

Two-spotted Spider Mites, Photo by David Handley

Two-spotted spider mites have been found exceeding the management threshold at one southern location this week, in a field that was under row covers. This is often where we first find mite problems. Expect mite problems to increase as the temperature increases, especially under dry conditions.

White grubs:  We have had several reports of white grub infestations in fields this spring. Weak plant growth may be the result of grubs feeding on roots. These grubs are the larvae of beetles, including European chafer and Asiatic garden beetle. The grubs have legs and a swollen anterior (rear end). The grubs can be found by pulling up weak plants and sifting through the soil that surrounded the roots.   Controlling white grubs when they are established in a field is difficult. Admire Pro® is labeled for control of white grubs and should be applied within two hours of irrigation or rainfall to get the chemical into the root zone. There is still time to apply nematodes to control the grubs. (Optimal timing is about mid-May.) Two species of nematodes appear to offer the best control. Heterorhabditis bacteriophora (Hb) is the best candidate when the soil temperature is above 60 degrees (‘J-3 Max Hb’ from The Green Spot Ltd., ‘GrubStake Hb’ from the Integrated Biocontrol Network, ‘Larvanem’ from Koppert Biological Systems.

Diseases:  Just a reminder that bloom is the critical time to protect strawberries from developing gray mold caused by the fungus Botrytis cinerea. Two to three sprays of fungicide during bloom are typically required to provide good protection against this disease. Any moisture, including irrigation, fog, or even pesticide sprays can stimulate Botrytis spores to germinate.  Fruit infections take place almost exclusively through the flowers, so gray mold control efforts must be focused on the bloom period.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

Highmoor Farm                       Pest Management
P.O. Box 179                             491 College Ave
Monmouth, ME  04259       Orono, ME  04473
207.933.2100                          1.800.287.0279

Maine Cooperative Extension, the Land Grant University of the state of Maine and the U.S. Department of Agriculture Cooperating.  Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.  A Member of the University of Maine System.

Any person with a disability who needs accommodations for these programs should contact Pam St. Peter at 207.933.2100 or TDD 1.800.287.8957 to discuss their needs at least 7 days in advance.

Where brand names or company names are used it is for the reader’s information.  No endorsement is implied nor is any discrimination intended against other products with similar ingredients.  Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.

 

Strawberry IPM Newsletter No. 1 – May 9, 2013

Monday, May 13th, 2013

StrawberriesStrawberry IPM Newsletter No. 1 – May 9, 2013

For full page print version, please see link at the bottom. Click on photos to enlarge.

Sprayer Calibration Clinic on May 21, 2013 at 2:00 p.m.
Twilight Meeting on May 21, 2013 at 5:00 p.m.
Pikes Farm to You in Farmington, Maine

2013 STRAWBERRY PEST MANAGEMENT SEASON BEGINS

Winter Injury Worries

Situation: What seemed to start as a relatively normal spring has now become a very dry spring indeed, with most areas in New England significantly behind on rainfall. While this has helped growers to get on to fields early to plant, established plantings of strawberries could be suffering from drought stress.  Dry conditions can also reduce nutrient uptake, resulting in deficiencies, most notably calcium. In southern locations, flower buds are now emerging from crowns in plantings that were mulched over the winter. Plantings that were not mulched are a little further advanced, and plantings that were under row covers are coming into bloom. Frost protection becomes a priority now, and irrigation should be set up to provide frost protection for buds and flowers on any night when temperatures drop below freezing.  Bear in mind that fields that are irrigated for frost repeatedly during bloom face an increased risk of bacterial angular leaf spot.

Frost Injury

Frost Injury, photo by David Handley

Winter injury is common in fields this spring, especially in plantings that either were not mulched or mulched late in the winter due to trouble getting onto the fields in the fall. Frost heaving is also apparent in fields with heavier soils, which injures plant roots and inhibits water and nutrient uptake.  Injured plants appear weakened, with small, dull colored leaves, and crowns that may be pushed out of the soil. Cutting into the crowns will reveal dark brown discoloration in the internal tissue. Helping plantings recover from winter injury involves compensating for the damaged vascular system.  Make sure the plants get plenty of water, especially in this dry period, and it may help to apply extra nutrients to encourage root growth and recovery, including nitrogen, calcium, and phosphorus. While we do not recommend heavy nitrogen fertilizer applications in the spring, up to 20 pounds of actual N (e.g. 125 lb. calcium nitrate) may improve early spring growth.

Sprayer Calibration Clinic & Twilight Meeting
The University of Maine Cooperative Extension and the Maine Vegetable and Small Fruit Growers Association will hold a sprayer calibration clinic for airblast sprayers at David Pike’s Farm to You in Farmington on Tuesday, May 21 at 2:00 p.m. George Hamilton with the University of New Hampshire Cooperative Extension will demonstrate new tools for making sure your sprayer is delivering the correct rate of pesticides to your crops. Having a sprayer properly calibrated will improve the effectiveness of your sprays, and can save you money by reducing the amount of pesticide used and reducing crop losses due to pests. Participants will receive two pesticide applicator re-certification credits.

The calibration clinic will be followed at 5:00 p.m. by a tour of David Pike’s strawberry and vegetable fields. David has been a leader in innovative strawberry production techniques, including raised beds, plastic mulch, fertigation, fall cropping, and season extension. There will be some new low tunnel technology on display, as well as replant experiments and new varieties on trial. One pesticide applicator re-certification credits will be awarded for the meeting. Hold the date! We’ll give driving directions next week.

2013-2014 New England Small Fruit Management Guides are now available at Highmoor Farm. This new, updated edition of the guide contains the latest information on management options for small fruit pests as well as cultural information. Cost of the guide is $10.00 plus $2.53 postage for a total of $12.53. Copies of the 2012-2013 New England Vegetable Management Guide with color pictures of the important pests and diseases are also available at Highmoor Farm. Cost of the guide is $25.00 plus $3.43 postage for a total of $28.43.

To order the guides, please send your check made payable to UMaine Cooperative Extension mailed to: Highmoor Farm, P.O. Box 179, Monmouth, Maine 04259, attention Pam St. Peter. For more information, contact Pam St. Peter at 933.2100 or pamela.stpeter@maine.edu.

Members of the Maine Vegetable & Small Fruit Growers Association (MVSFGA) or the New England Vegetable & Berry Growers Association receive free copies of the guides. For MVSFGA membership information, contact Bill Jordan at 799.1040.

Scouting
We will start scouting strawberry fields for major insect pests in earnest next week, including volunteer farms, in North Berwick, Wells, Cape Elizabeth, Poland Spring, New Gloucester, Dresden, Monmouth, Wayne, and Farmington, and will be reporting our findings through this newsletter on a weekly basis until harvest time. You can also get quick access to this information through the Highmoor Farm blog or the Pest Management web page.  If you would prefer to receive this message via e-mail, please give us a call at 933.2100 or send an e-mail message to: pamela.stpeter@maine.edu.

The best way to manage strawberry pests is to scout your own fields regularly and often. You should start scouting regularly as soon as flower buds emerge from the crown. You should be able to identify the major pests and their damage, and be able to determine if control measures are necessary. To properly scout your fields you may want a copy of the Strawberry Production Guide for the Northeast, Midwest and Eastern Canada. This contains detailed information on strawberry pest identification and monitoring, and also provides information on all other aspects of strawberry production. It may be purchased for $45.00 per copy from the University of Maine Cooperative Extension online Publications Catalog.  You should also have a copy of the 2013-2014 New England Small Fruit Pest Management Guide, which contains the latest information on management  options for the major strawberry pests as well as scouting information.

Clipper Beetle on Strawberry Bud

Clipper Beetle on Strawberry Bud, photo by James Dill

Strawberry bud weevil or “clipper” will soon be active as flower buds begin to emerge. The clipper is a small weevil, which girdles strawberry flower buds, causing them to dry up and fall off the flower stalk.  Scout for damage by counting the number of clipped buds in two feet of row length at five different locations in a field. If the average number of clipped buds per two-foot sample exceeds 1.2, or if live clippers are found, control measures are recommended. Damage is usually first noticed at the edges of the field. Border sprays may be effective in keeping this insect from becoming a problem in larger fields. Fields with a history of clipper problems will typically exceed threshold nearly every year.  Insecticide options for clipper include Lorsban®, Brigade®, Sevin® and PyGanic®.

Tarnished Plant Bug Adult

Tarnished Plant Bug Adult, photo by David Handley

Tarnished plant bugs adults have been found in southern Maine, indicating that they will soon be laying eggs. Strawberries are one of their preferred hosts at this time of year. Once the eggs start to hatch, we’ll find the nymphs feeding in the flowers.  The nymphs are small, active, yellow-green insects.  It is important to scout for them regularly, as they can appear very quickly in warm weather. Tarnished plant bugs feed on the open strawberry flowers, causing the berries to have seedy ends. To scout for the nymphs shake 30 flower clusters (six clusters in five different locations) over a plate. If four or more of the clusters out of the 30 sampled have any nymphs, control measures should be taken. Be on the alert and scout your fields now!  Insecticide options for tarnished plant bug include malathion, Brigade®, Danitol®, Thionex® and PyGanic®.

Cyclamen Mite Damage

Cyclamen Mite Damage, photo by David Handley

Cyclamen mites:  Plants showing weak growth and yellow, pinkish or blackened, crinkled leaves may be infested with cyclamen mite. Cyclamen mites are very small, smaller than spider mites, and reside in the crown of the strawberry plant feeding on the developing leaves and flower buds. They are very hard to see, even with magnification. Infested plants have shrunken distorted leaves and flower stalks, and produce few, if any, marketable fruit. Miticides such as Thionex® or Kelthane® and Temprano® can be effective, but must be applied in lots of water to be sure that the material is carried down into the crowns where these mites reside.

Two-spotted Spider Mites

Two-spotted Spider Mites, photo by David Handley

Two-spotted spider mites have not yet been a problem this spring, but growers with plants under row covers should be alert. This is often where we first find mite problems. Spider mites will reproduce rapidly when warmer weather arrives, so it is important to scout for them regularly. Spider mites feed on the undersides of strawberry leaves, rasping the plant tissue and sucking the sap. Infested leaves will develop yellow flecking and a bronzed appearance. The plants become weakened and stunted. Fields that have had excessive nitrogen fertilizer and/or row covers tend to be most susceptible to mite injury. To scout for mites, collect 60 leaves from various locations in the field and examine the undersides for the presence of mites.  Mites are very small – you may need a hand lens to see them.  Chemical control options for two-spotted spider mites include Acramite®, Savey®, Zeal®, Vendex®, Oberon®, Brigade®, Danitol®, Thionex® and JMS Stylet oil ® (oils will cause plant injury if used in combination with captan or within 14 days of an application of sulfur).

Strawberry Root Weevil Grub

Strawberry Root Weevil Grub, photo by David Handley

Root weevil management
Fields that were infested with root weevils last summer should be inspected for grubs this spring. Infested plants appear week and stunted, usually in somewhat circular patches in a field. Digging under the plants will reveal small (1/4”-1/2”) crescent-shaped legless grubs. Typically, the grubs begin to pupate when the plants are in bloom. A soil drench of Platinum® (thiamethoxam) insecticide during the spring and/or fall when the grubs are active in the soil can provide control. However, Platinum® has a 50 day pre-harvest interval, so it is too late for applications in most fruiting fields this year.  Platinum® may also be used as a pre-plant or planting treatment for root weevils.  It is not too late to put on an application of nematodes to control the grubs (optimal timing is about mid-May). Two species of nematodes appear to offer the best control of root weevil grubs. Heterorhabditis bacteriophora (Hb) appears to be the best candidate for control of root weevils when the soil temperature is above 60 degrees (‘J-3 Max Hb’ from The Green Spot Ltd., ‘GrubStake Hb’ from the Integrated Biocontrol Network, ‘Larvanem’ from Koppert Biological Systems).

Nematodes are living organisms and they can be killed if they are misapplied. Order nematodes ahead of time and be ready to apply them through a sprayer or irrigation soon after they arrive. Refrigerate them if you can not apply right away. Do not apply nematodes using a sprayer with a piston pump. Use clean equipment, removing all screens finer than 50-mesh. Apply nematodes in early morning or evening in a high volume of water to already moist soil, pre-irrigating if needed. Apply another ¼ inch of irrigation after application to wash them onto and into the soil. Researchers and suppliers recommended 250 (if banded in the row) to 500 million per acre, at a cost of $100-$200 per acre depending on volume and source. Nematodes tend to work best in heavily infested fields. Strawberry plants can recover their vigor remarkably well if crown feeding has not occurred and diseases haven’t taken over the roots.

Once the adults become active in July, bifenthrin (Brigade®) will provide some control if used at the highest labeled rates. The best timing for this spray is at night during the peak feeding activity of adults, before they start laying eggs, or about the time harvest ends.

White Grub

White Grub, Photo by David Handley

White grubs:  Weak growth noted in fields this spring may also be the result of white grubs feeding on the roots of newer plantings. These grubs are the larvae of beetles, including European chafer and Asiatic garden beetle. They differ from the larvae of black vine weevil and strawberry root weevil in that they have legs and a swollen anterior (rear end), and they tend to be larger. Their feeding weakens the plants by reducing the number of roots. The grubs can be found by pulling up weak plants and sifting through the soil that surrounded the roots.   Controlling white grubs once they have become established in a field can be difficult. These tend to be more of a problem in new fields that have been planted following a grass rotation crop, because the adults prefer to lay their eggs in sod. Admire Pro®  and Platinum® insecticides are labeled for control of white grubs and should be applied within two hours of irrigation or rainfall to be sure the chemical gets into the root zone. Admire Pro® requires a 14 day to harvest interval, while Platinum® requires a 50 day pre-harvest interval.

Gray Mold on Strawberries

Gray Mold on Strawberries, photo by James Dill

Diseases:  Bloom is a critical time to protect strawberry fruit against gray mold caused by the fungus Botrytis cinerea, especially when conditions have been damp. Two to three sprays of fungicide during bloom are typically required to provide good protection against this disease. If you tank mix insecticides and fungicides, avoid spraying when bees are active. Botrytis cinerea overwinters on old leaves and plant debris. Fruit infections take place almost exclusively through the flowers, so gray mold control efforts must be focused on the bloom period.  If the bloom period is dry and/or good fungicide coverage is maintained, incidence of gray mold at harvest should be low.

There are several excellent fungicide choices for control of gray mold in strawberries. Elevate® (fenhexamid) has good to excellent activity against Botrytis. Captevate® is a pre-mix of captan and fenhexamid and has a broader spectrum of activity than Elevate® alone. Switch® (cyprodinil and fludioxonil), Scala® (pyramethanil) and Pristine® (pyraclostrobin and boscalid) are also excellent products for gray mold control.  Topsin M® + captan is also a good fungicide combination, but remember that captan is strictly a protectant and can be washed off by rain or irrigation water. Thiram is similarly effective but also susceptible to wash-off.

The fungicides Cabrio® (pyraclostrobin) and Abound® (azoxystrobin) are NOT suitable for gray mold control, but are effective against anthracnose and other fruit rot and leaf spot diseases. All fungicides mentioned above have a 0-day pre-harvest interval, except Topsin M® (1 day) and thiram (3 days). Remember to alternate fungicides with different modes of action for resistance management purposes.

Red stele root rot
Although fall and early spring conditions were not especially conducive to red stele development, damp conditions this spring should make us alert for this root rot if any fields appear to be weak, stunted or dying. To diagnose red stele, pull up a few plants that look weak and scrape the roots of these plants to see if the center of the root, known as the stele, is rusty red in color, instead of the normal white. The red color would indicate an infection.  Red stele is caused by Phytophthora fragariae, a soil pathogen that infects roots when soils are wet with temperatures around 50°F. The pathogen grows into the roots causing the plants to become weak, stunted and to eventually die. Symptoms are most evident in the spring, and can be mistaken for winter injury. Ridomil Gold®, Alliette® or Phostrol® are fungicides that can be applied in the late fall or early spring for control of red stele.  Many varieties have some level of resistance to the disease, but the most effective management strategy is to plant only into well-drained soils, and/or plant onto raised beds.

Powdery Mildew

Powdery Mildew, photo by David Handley

Powdery mildew:  This fungus disease may first show up as purple or red blotches on the leaf petioles and flower stems in strawberry fields. Most of us are more familiar with the later symptoms of upward curling of the leaves and white, powdery growth on the undersides of the leaves. Check your fields for pinkish purple leaf and flower stem lesions as new leaves emerge. Pristine®, Cabrio®, Topsin-M®, captan, Procure®, Torino® and JMS Stylet oil® are presently registered to control powdery mildew.

 

Angular Leaf Spot

Bacterial Angular Leaf Spot, Photo by David Handley

Angular leaf spot is a bacterial disease that is characterized by translucent leaf spots that may turn yellow and eventually black. The symptoms tend to start on the lower leaves but may move upwards as bacterial spores are splashed up by rain or irrigation water. Infection of the calyxes may result in a blackening of the berry stems and caps, reducing their marketability. Bacterial angular leaf spot is favored by extended cool, wet weather and nights with temperatures close to freezing. Frequent irrigation for frost protection can greatly encourage the development and spread of the disease, as will extended cool, damp weather. Susceptibility to this disease appears to vary significantly between varieties. The copper containing material Kocide®, can reduce the spread of this disease. Start spray applications before bloom to prevent multiplication of the bacteria on the leaves before they jump to the berry caps. Application of copper sprays after bloom can result in fruit injury and is not recommended. Hydrogen dioxide (OxiDate®) may also have some activity against angular leaf spot when used on strawberries as part of a gray mold management program.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

Highmoor Farm                                   Pest Management
P.O. Box 179                                         491 College Ave
Monmouth, ME  04259                    Orono, ME  04473
207.933.2100                                      1.800.287.0279

Maine Cooperative Extension, the Land Grant University of the state of Maine and the U.S. Department of Agriculture Cooperating.  Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.  A Member of the University of Maine System.

Where brand names or company names are used it is for the reader’s information. No endorsement is implied nor is any discrimination intended against other products with similar ingredients. Always consult product labels for rates, application instructions and safety precautions. Users of these products assume all associated risks.

Sweet Corn IPM Newsletter No. 14 – September 17, 2012

Monday, September 17th, 2012

Sweet Corn

For full page print version, please see link at the bottom.  Click on photos to enlarge.

Last Issue for 2012

ANY FRESH SILKING CORN REMAINING NEEDS PROTECTION

Corn Earworm Still a Threat to Late Corn

This will be the final issue of the Sweet Corn IPM Newsletter for the 2012 season.  I would like to thank all of the growers who participated in the program this year, and our team of IPM scouts including John Banville, Tammy Cushman, Chase Gaewski, Griffin Dill and Sean McAuley, with help from John Hutton and Kara Rowley.  Special thanks go to Katie Woodman who coordinated the team.

SITUATION
Hurricane Isaac appears to have only caused a mild bump in pest numbers over the past week, and it is likely that cooler temperatures will slow pest activity in the coming days.  Any silking corn remaining requires protection from corn earworm statewide, but fall armyworm and European corn borer are only at problem levels in a few sites.

European corn borer:  Moth counts continued to be very low last week in most locations.  Although fields in Oxford and Wayne exceeded the 5-moth threshold for silking corn, which suggests the start of a second generation.  Both sites are on spray schedules for corn earworm, so no additional sprays were needed.  Feeding damage was found in a pre-silking field in Biddeford, and exceeded the 15% threshold when combined with fall armyworm damage.

European Corn Borer Larva on Ear

European Corn Borer Larva on Ear, photo by David Handley

Corn earworm:  Moth counts were generally higher last week, returning many fields to tighter spray intervals on fresh silking corn.  A 4-day spray interval for silking corn was recommended for Cape Elizabeth, Dayton, Levant, New Gloucester, Nobleboro, North Berwick, Wales,Wayne and Warren.  A 5-day spray interval was recommended for Biddeford, Dresden, Lewiston, and one Wells location.  A 6-day spray interval was recommended for Jefferson, Oxford, Poland Spring and Wells.

Corn Earworm

Corn Earworm, photo by David Handley

Fall armyworm:  Most fields are under spray schedules for corn earworm, so little feeding damage is being noted.  Only one Biddeford field was over the threshold when combined with ECB feeding damage.  Moth captures remained low, with only one field in Levant exceeding the spray threshold of 3 moths in silking corn.  Single moths were caught in Lewiston, Monmouth and New Gloucester.

Adult Fall Armyworm

Adult Fall Armyworm, photo by David Handley

It’s time for cover crops!
Plowing down corn stalks destroys the over wintering sites of European corn borer, but late plowing can leave soil prone to erosion during the winter and spring.  Planting winter rye is a good option for many fields.  It can be planted well into September to produce enough of a cover to prevent erosion. Rye will survive the winter and put on more growth in the spring.  It should be killed by plowing, mowing or herbicide before it goes to seed.  Having rye on the field may delay planting in the spring, as you must wait for conditions to be warm and dry enough to plow it in.  Animal manures can also be applied to soils in early fall and incorporated to improve soil structure and provide nutrients.  Cover crops should be seeded after manure applications to absorb and hold nutrients, which will be released after the crop is plowed down the following spring.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

Highmoor Farm                      Pest Management Office
P.O. Box179                          491 College Ave
Monmouth,ME 04259            Orono,ME 04473
207.933.2100                       1.800.287.0279

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Biddeford 5 0 0 24% 5-day spray interval for all silking corn
Cape Elizabeth I 9 0 0 All Silk 4-day spray interval for all silking corn
Cape Elizabeth II 18 0 0 All Silk 4-day spray interval for all silking corn
Dayton I 8 0 0 All Silk 4-day spray interval for all silking corn
Dresden 4 0 0 All Silk 5-day spray interval for all silking corn
Jefferson 2 0 0 All Silk 6-day spray interval for all silking corn
Levant 15 0 3 All Silk 4-day spray interval for all silking corn
Lewiston 6 0 1 All Silk 5-day spray interval for all silking corn
Monmouth 0 0 1 All Silk No spray recommended
New Gloucester 38 0 1 All Silk 4-day spray interval for all silking corn
Nobleboro 33 0 0 All Silk 4-day spray interval for all silking corn
North Berwick 17 0 0 All Silk 4-day spray interval for all silking corn
Oxford 3 13 0 All Silk 6-day spray interval for all silking corn
Poland Spring 2 1 0 All Silk 6-day spray interval for all silking corn
Wales 23 1 0 All Silk 4-day spray interval for all silking corn
Wayne 11 10 0 All Silk 4-day spray interval for all silking corn
Warren 9 0 0 All Silk 4-day spray interval for all silking corn
Wells I 3 0 0 All Silk 6-day spray interval for all silking corn
Wells II 5 0 0 All Silk 5-day spray interval for all silking corn

CEW:  Corn earworm (Only fresh silking corn should be sprayed for this insect.)
ECB:   European corn borer
FAW:  Fall armyworm

Corn Earworm Spray Thresholds for Pheromone Traps

Moths caught per week Moths caught per night Spray interval
0.0 to 1.4 0.0 to 0.2 No spray
1.5 to 3.5 0.3 to 0.5 Spray every 6 days
3.6 to 7.0 0.6 to 1.0 Spray every 5 days
7.1 to 91 1.1 to 13.0 Spray every 4 days
More than 91 More than 13 Spray every 3 days

Thresholds apply only to corn with exposed fresh silk. Lengthen spray intervals by one day if maximum daily temperature is less than 80°F.

European Corn Borer Thresholds
Whorl stage: 30% or more of plants scouted show injury.
Pre-tassel-silk: 15% or more of plants scouted show injury.
Silk: 5 or more moths caught in pheromone traps in one week.

IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/

Where brand names or company names are used it is for the reader’s information.  No endorsement is implied nor is any discrimination intended against other products with similar ingredients.  Always consult product labels for rates, application instructions and safety precautions.  Users of these products assume all associated risks.

Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the State of Maine and the U.S. Department of Agriculture cooperating.  Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.

Sweet Corn IPM Newsletter No. 13 – September 5, 2012

Wednesday, September 5th, 2012

Sweet Corn

For full page print version, please see link at the bottom.  Click on photos to enlarge.

CORN EARWORM REMAINS LOW…  FOR NOW…

Fall Armyworm and European Corn Borer also Remain Scarce

SITUATION
This is a somewhat abbreviated issue, due to the Labor Day holiday and a much reduced scouting team this week.  In addition, it does not include the potential impact of the remains of hurricane Isaac, which are passing over Maine today.  Although insect counts have been very low for this time of year, the passing of a tropical storm can bring with it a significant population of corn pests, especially corn earworm and fall armyworm, so we should anticipate higher pressure by the end of the week for any fresh silking corn remaining in the field.

European corn borer:  Moth counts are very low this week with only one site in Cape Elizabeth exceeding the 5-moth threshold for silking corn, but the site is also on a spray schedule for corn earworm, so no additional sprays are needed.  Feeding damage was also low.  Only a North Berwick field exceeded the 15% threshold when combined with fall armyworm damage.

Corn earworm:  Moth counts were at low to moderate levels this week, although we anticipate increased activity due to the tropical storm remnants passing through Maine today.  A 4-day spray interval for fresh silking corn was recommended for one Dayton location and Nobleboro.  A 5-day spray interval was recommended for Cape Elizabeth, Dayton, New Gloucester, North Berwick,Wayne and Warren.  A 6-day spray interval was recommended for Biddeford, Charleston, Jefferson, Monmouth, Wales and Wells.

Corn Earworm Moth

Corn Earworm Moth, photo by David Handley

Fall armyworm:  Most fields are now in silk and under spray schedules for corn earworm, so very little feeding damage is being noted.  Only one North Berwick field was over the threshold when combined with ECB feeding damage.  Moth captures remain low for this time of year, with no sites exceeding the spray threshold of 3 moths in silking corn.  Single moths were caught in Biddeford, Cape Elizabeth, Monmouth, New Gloucester, and Warren.

Male Fall Armyworm Moth

Male Fall Armyworm Moth, photo by David Handley

The Food Safety Modernization Act (FSMA) and Its Possible Effects on Maine’s Specialty Crop Growers
AgMatters LLC cordially invites you to attend a workshop about this important new legislation.  Joy Johanson from the Produce Safety staff with the FDA will give an overview of FSMA and the Produce Safety Rule.  Representatives from the Maine Board of Pesticides Control will address Worker Protection Training and a new law requiring Pesticide Licensing of all growers.  Lauchlin and Linda Titus from AgMatters LLC will share their impressions on the future of Maine’s Specialty Crop Markets and suggestions on how growers can capitalize on changes in the industry.  Please register for one of the following times and locations:

Tuesday, September 11, 2012
10:00 AM to 2:00 PM
Bangor Motor Inn, 701 Hogan Rd., Bangor (Exit 187 off Interstate 95)
Tel. 207.947.0355

Or

Wednesday, September 12, 2012
10:00 AM to 2:00 PM
Ramada Inn, 490 Pleasant St., Lewiston (Exit 80 off Interstate 95)
Tel. 207.784.2331

Please RSVP as soon as possible by phone 873.2108 or by email to ltitus21@myfairpoint.net.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

Highmoor Farm                      Pest Management Office
P.O. Box179                          491 College Ave
Monmouth,ME 04259            Orono,ME 04473
207.933.2100                       1.800.287.0279

Sweet Corn IPM Weekly Scouting Summary

Location CEW Moths ECB Moths FAW Moths %Feeding Damage Recommendations / Comments
Biddeford 2 0 1 8% 6-day spray interval for all silking corn
Cape Elizabeth I 5 5 0 All silking 5-day spray interval for all silking corn
Cape Elizabeth II 5 1 1 4% 5-day spray interval for all silking corn
Charleston 3 2 0 All silking 6-day spray interval for all silking corn
Dayton I 15 0 0 All silking 4-day spray interval for all silking corn
Dayton II 6 0 0 All silking 5-day spray interval for all silking corn
Jefferson 3 0 0 All silking 6-day spray interval for all silking corn
Monmouth 2 1 1 All silking 6-day spray interval for all silking corn
New Gloucester 5 0 1 All silking 5-day spray interval for all silking corn
Nobleboro 14 1 0 All silking 4-day spray interval for all silking corn
No. Berwick 7 0 0 All silking 5-day spray interval for all silking corn
Sabattus 0 0 0 All silking No spray recommended
Wales 2 0 0 All silking 6-day spray interval for all silking corn
Warren 5 2 1 All silking 5-day spray interval for all silking corn
Wayne 4 0 0 All silking 5-day spray interval for all silking corn
Wells I 2 0 0 All silking 6-day spray interval for all silking corn
Wells II 3 0 0 All silking 6-day spray interval for all silking corn

CEW: Corn earworm (Only fresh silking corn should be sprayed for this insect.)
ECB:  European corn borer
FAW: Fall armyworm

Corn Earworm Spray Thresholds for Pheromone Traps

Moths caught per week Moths caught per night Spray interval
0.0 to 1.4 0.0 to 0.2 No spray
1.5 to 3.5 0.3 to 0.5 Spray every 6 days
3.6 to 7.0 0.6 to 1.0 Spray every 5 days
7.1 to 91 1.1 to 13.0 Spray every 4 days
More than 91 More than 13 Spray every 3 days

Thresholds apply only to corn with exposed fresh silk.  Lengthen spray intervals by one day if maximum daily temperature is less than 80°F.

European Corn Borer Thresholds
Whorl stage:  30% or more of plants scouted show injury.
Pre-tassel-silk:  15% or more of plants scouted show injury.
Silk:  5 or more moths caught in pheromone traps in one week.

IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/

Where brand names or company names are used it is for the reader’s information.  No endorsement is implied nor is any discrimination intended against other products with similar ingredients.  Always consult product labels for rates, application instructions and safety precautions.  Users of these products assume all associated risks.

Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the State of Maine and the U.S. Department of Agriculture cooperating.  Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.