Posts Tagged ‘pest management’

Strawberry IPM Newsletter No. 5 – June 20, 2014

Friday, June 20th, 2014

StrawberriesStrawberry IPM Newsletter No. 5 – June 20, 2014

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HARVEST STARTS IN SOUTHERN MAINE

Spider Mites and Leaf Diseases Active

Situation:  Strawberry picking is underway in southern Maine this week, with many farms opening for pick-your-own customers this weekend. Overall, the crop looks good to very good, in spite of some winter injury and a cool, wet start to the season. It also looks as though we will have good weather for opening weekend customers. The Strawberry IPM Newsletter, will take a couple of weeks off while we enjoy the harvest and will be back with our Renovation Issue in July.

Large Tarnished Plant Bug Nymph

Third Instar Tarnished Plant Bug Nymph, photo by David Handley

Tarnished plant bug nymphs were absent in many fields this week and in low numbers wherever they were found. Only one field exceeded the control threshold of 4 flower clusters infested with nymphs out of 30 sampled. If you still have blossoms remaining in your field, it is important to keep scouting for nymphs into the green fruit stage to prevent injury.

Two-spotted spider mites:  Two fields we scouted this week were over the control threshold of 25% of leaves infested; but most fields had very few, if any, mites present. As drier weather sets in, mite populations will likely begin to increase. Continue scouting for mites during the summer after bed renovation, to prevent a build up that could weaken the plants during flower bud development.

Two-spotted Spider Mites

Two-spotted Spider Mites, photo by David Handley

Strawberry Root Weevil Grub

Strawberry Root Weevil Grub, photo by David Handley

If black vine weevils or strawberry root weevils are a problem in a strawberry field that you would like to carry over, bifenthrin (Brigade®) can be applied to control the beetles when their feeding is noticed (usually until mid- to late-July). Grubs are now beginning to pupate in the soil, and the adult weevils will begin to emerge in a few weeks. Look for notching along the leaf edges and the presence of the black or brown snout beetles during the evening. Applications should be made at night when these insects are active, and the highest allowable rate of the insecticide should be used.

Powdery Mildew

Powdery Mildew, photo by David Handley

Leaf Spot on Strawberry Plant

Leaf Spot, photo by David Handley

Diseases:  Dry weather predicted for the upcoming week should provide some relief from the threat of fruit rots, including gray mold and leather rot. However, foliar diseases, including powdery mildew and leaf spot can continue to flourish under drier conditions if infections have already occurred. If you still have significant bloom remaining in the field, you may still need to apply a fungicide to protect against gray mold, especially if rain is predicted in your area, or you plan to overhead irrigate the planting.

Keep an eye out for anthracnose fruit rot as berries begin to ripen in the field.  Infected fruit show sunken patches of brown or black. Whole fruit may suddenly turn soft or dry up to blackened mummies. This is usually a problem when fields have standing water present and warm temperatures. I haven’t seen anthracnose in the fields I have visited so far, but be aware that this could still become a problem. Effective fungicides include Cabrio® and Abound®.

Spraying Pesticides on Raspberries Using Backpack

Spraying Pesticides on Raspberries, photo by Jill Stanley

Important Reminder for Pesticide Users
Fruit, vegetable or grain growers who use general use (over-the-counter) pesticides and annually sell more than $1,000 of plants or plant products intended for human consumption will be required to have an Agricultural Basic Pesticide Applicator License by April 15, 2015. In the past, only farmers using restricted use pesticides were required to have a pesticide applicators license. The new law extends the licensing requirement to all commercial growers who use pesticides. Training and testing sessions for unlicensed farmers will be held across the state this fall and winter. For more information contact the Pest Management Office at 1.800.287.0279.

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 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.

Strawberry Harvest

Strawberry Harvest, photo by David Handley

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 a look at our checklist and 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.

Websites Worth Visiting
If you are looking for information to help diagnose a problem in your strawberries or need a recommendation for a control strategy, the 2013-2014 New England Small Fruit Management Guide is available online. You should also check out Cornell University’s Berry Diagnostic Tool online.

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 – June 13, 2014

Friday, June 13th, 2014

StrawberriesStrawberry IPM Newsletter No. 4 – June 13, 2014

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EARLY FIELDS GETTING READY FOR HARVEST

Tarnished Plant Bugs, Spider Mites and Leaf Diseases Active

Situation:  Strawberry development continues to be slow, as we can’t seem to string together more than a couple of warm days before the cool damp weather creeps back in. Despite the clouds, many fields are starting to get a bit dry; although rain predicted for this weekend may bring those fields some needed moisture. Overall, most fields look very good, with good plant vigor and fairly heavy bloom. Turn out for our twilight meeting at Fairwinds Farm in Bowdoinham was very good, and we thank Pete and Cathy Karonis for their hospitality. Many of the strawberry growers there were hoping to start picking next week and perhaps opening for pick-your-own next weekend. It looks like we’ll have a good crop for July 4th.

Strawberry bud weevil or “clipper” is very active in late flowering varieties and raspberries this week. Most early and mid-season varieties are now beyond the point at which clippers can cause significant damage. Two fields scouted this week were over threshold for clipped buds. Remember that clippers will move onto raspberries to clip flower buds after strawberry bloom.

Clipper Beetle on Strawberry Blossom

Clipper Beetle on Strawberry Blossom, photo by David Handley

First Instar Tarnished Plant Bug Nymph

First Instar Tarnished Plant Bug Nymph, photo by David Handley

Tarnished plant bug nymphs are present in most fields this week, but in most cases were not over the threshold of 4 flower clusters infested with nymphs out of 30 sampled. Most of the nymphs found were still in the very small, bright yellow-green phase. It is important to keep scouting for nymphs through the bloom period and into the green fruit stage because feeding damage can still occur, causing misshapen, seedy berries.

Two-spotted spider mites were present in most fields scouted this week but, with one exception, they were well under the threshold of 25% of leaves infested. Cool, damp weather generally keeps mite populations in check naturally, but they can increase rapidly under hot, dry conditions, so it is important to keep scouting for them.

Cyclamen Mite Damage

Cyclamen Mite Damage, photo by David Handley

Cyclamen mites:  We continue to find fields with cyclamen mite infestations. Usually symptoms are first noticed in beds that are two or three years old.   Infested plants show weak growth and yellow, crinkled leaves. The flower stems are small and short and the petals are deformed and sometimes look pink.  The symptoms can be confused with winter injury, herbicide injury or virus infection. Cyclamen mites reside on undeveloped leaves and flower clusters down within the crown of the strawberry plants, and can be very hard to see, even with magnification. Miticide applications must be applied with lots of water (40-100 gals./acre) to be sure that the material reaches the mites.

Sap beetles sometimes become a problem when fruit starts 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. Brigade®, Assail® 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.

Slug on Strawberry

Slug on Strawberry, photo by James Dill

Slugs may also start feeding on strawberries as they start to ripen. Moist conditions and mulch encourage the presence of slugs. They feed at night, leaving large holes and tunnels in ripening fruit and shiny slime trails on the leaves. Baits such as Deadline® and Sluggo® offer some control of slugs, and should be used prior to fruit ripening. Avoid contacting the developing fruit with the bait. Pay close attention to label instructions and precautions. Slugs overwinter in the egg stage, so baits applied to the fields in mid-September can effectively reduce egg-laying.

Diseases:  Many fields are now past the most susceptible bloom stage for primary infection by Botrytis spores. Fungicides applied during bloom should provide adequate protection against gray mold unless fields get lots of rain post-bloom. If more than one inch of rain has fallen since your last fungicide application, it is likely that the fruit are no longer protected, and another application may be warranted.

Leather rot (Phytopthora cactorum):  Most fields have dried out very well over the past week, reducing the chance of leather rot infections. If you have standing water in your fields during the bloom or early fruit development period, you may want to consider a fungicide application to prevent leather rot. Remember that fungicides applied for gray mold are generally not effective for leather rot. Aliette®, Agri-Phos® or Phostro® are considered most effective.

Powdery mildew:  Warmer, humid weather has increased the symptoms of powdery mildew in fields this week. Many plants are starting to show red streaks on the leaf and flower stems, upward curling leaves, and white, powdery growth on the leaf undersides. Keep an eye out for leaf cupping in your fields and, if you need to apply another fungicide for gray mold, add a material that will also provide control of powdery mildew, such as Pristine®, Topsin-M®, or captan.

Leaf Spot

Leaf Spot, photo by David Handley

Leaf Scorch

Leaf Scorch, photo by David Handley

Leaf spot infections are becoming more common in strawberry fields this week. The spots usually appear on older leaves first, as small purple or red spots with white centers. Leaf scorch has also been noted in a couple of fields. The spots are smaller in the case of scorch, and lack the white centers. Spots may coalesce to turn the leaves purple and brown, leading to the death of the leaf and weakening of the plant. Many strawberry varieties have at least partial resistance to leaf spot and leaf scorch. Fungicides registered for leaf spots include captan, Topsin-M®, Cabrio®, and Pristine®.

Bird Damage on Strawberry

Bird Damage on Strawberry, photo by David Handley

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 keep them at bay. They are often discouraged once people start to occupy the fields much of the day to harvest. Cedar waxwings are songbirds and are protected by law. They should not be killed. However, the U.S. Fish and Wildlife Service may issue permits for killing birds 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. However, the permit is good for one year; so if you have problems this season, you may consider applying for a permit this winter, which would allow you the option to kill birds, if necessary, next season. The Wildlife Damage Office has recommendations for managing birds in crops, and also has some control options available through their office. For more information on permits or bird control contact the office in Augusta at 207.629.5181. The office is located in the Capital West Business Center, 79 Leighton Road in Augusta.

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 – June 6, 2014

Monday, June 9th, 2014

Strawberries

Strawberry IPM Newsletter No. 3 – June 2014

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STRAWBERRY GROWTH SLOW BUT STEADY AS HARVEST APPROACHES

Clippers, Tarnished Plant Bugs, and Spider Mites Active

Vegetable and Berry Growers Twilight Meeting
Wednesday, June 11, 2014 at 5:30 p.m.
Fairwinds Farm, Bowdoinham, Maine

Situation: The temperatures have remained fairly cool with more damp, cloudy days and, as a result, strawberry development has been relatively slow but steady as we head towards harvest time. A later start may be a good thing for pick-your-own fields, as it will better coincide with the end of the school year; but a few days of warm weather would really speed development. Most early varieties are now in the small green fruit stage, while later varieties are still in bloom. Early fields that started under row covers may be picking a few fruit next week.

Twilight Meeting
The University of Maine Cooperative Extension and the Maine Vegetable and Small Fruit Growers Association will hold a twilight meeting at Fairwinds Farm in Bowdoinham on Wednesday, June 11 at 5:30 p.m. Pete and Cathy Karonis grow 10 acres of strawberries and approximately 40 acres of mixed vegetables in fields along the Kennebec River and have a farmstand and greenhouses in Topsham. They will host a tour of their strawberry, raspberry and vegetable plantings, and describe their growing and marketing practices. In addition, we’ll discuss the upcoming season and pest management issues facing vegetable and berry growers this year. One pesticide applicator recertification will be awarded for the meeting. Hold the date! We’ll meet at the strawberry fields in Bowdoinham.

From I-295, take Exit 37. Turn east towards Bowdoinham onto Route 125/138 South. Travel 1.4 miles to the stop sign, then turn left onto Route 24 North/River Road. Travel 0.7 mile and turn right onto Brown’s Point Rd. Go 2.6 miles (road veers to the right and becomes a dirt road) and the farm is on the left, across from 555 Brown’s Point Road. (Use this address for GPS reference. Signs will be posted.) Their contact information is: tel. 207.522.5064 or 207.522.0246, email fairwindsfarm08@gmail.com.

Strawberry bud weevil or “clipper” is still working in fields of late varieties that still have lots of unopened flower buds. Fields that have reached full bloom or beyond no longer need to be scouted for clipper. Damage in most fields remains fairly light, as early varieties went into bloom before clipper became very active. Three of the fields scouted this week were just over threshold for clipped buds, and clippers have been observed in other fields where the damage had not yet reached threshold.

Reminder to raspberry growers: Strawberry clipper will move onto raspberry buds after strawberry bloom. Check raspberry flower clusters for clipped buds and live clippers. Insecticide sprays to control raspberry fruit worm adults (which are also active at this time) should provide some control of clipper as well. Products registered for clipper on raspberries include Brigade®, Sevin XLR Plus® and Aza-Direct®.

Clipper Damage on Strawberry Plant

Clipped Flower Buds from Strawberry Clipper, photo by David Handley

Large Tarnished Plant Bug Nymph

Third Instar Tarnished Plant Bug Nymph, photo by David Handley

Tarnished plant bug nymphs were over threshold in two fields scouted this week, but most fields still showed very little tarnished plant bug activity. However, it is important to keep scouting for nymphs throughout the bloom period because they can appear very quickly under warmer, drier conditions. Insecticide options for tarnished plant bug include malathion, Assail®, Brigade®, Bifenture®, Danitol®, and PyGanic®.

Strawberry Rootworm Beetle

Strawberry Rootworm Beetle, photo by David Handley

Strawberry rootworm (not root weevil) adults and feeding injury were reported on strawberry plants last week The adult stage of this insect is a small (1/8”) dark brown beetle. The beetles feed on strawberry leaves during the spring and late summer, causing numerous small holes in the leaves. The adults in fields now will soon lay eggs. The larvae are small grubs that feed on the roots of strawberry plants, causing them to be stunted and weak.  If these beetles and/or feeding injury is prevalent in a field, a treatment is recommended. Sevin 50WP® is registered for control of this pest, and sprays targeted at other insect pests at this time may also control rootworm. Strawberry rootworm should not be confused with root weevil, a larger insect that causes much more serious damage when present in a field.

Two-spotted spider mites were over the threshold (25% of leaves infested) in two locations this week, and smaller populations (under threshold) have been found in most fields. Mites can proliferate rapidly under hot, dry conditions, so it is important to scout for them often. 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).

Cyclamen mites:  Two more fields we’ve scouted have shown symptoms of cyclamen mite injury this week. Infested plants show weak growth and yellow, crinkled leaves. The flower stems are small and short and the petals are deformed and sometimes look pink.  Cyclamen mites are very hard to see, even with magnification. Portal®, Kelthane® or Thionex® 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.

Spittlebug

Spittlebug, photo by David Handley

Spittlebugs: The frothy spittle masses on the leaf and flower stems from spittlebugs usually show up around bloom. Spittlebugs don’t pose a significant threat to the plants, but the spittle masses are a nuisance for pickers. Spittlebugs overwinter as eggs and the nymphs emerge in late May. Scouting for spittlebugs should start when the plants are at 10% bloom. Randomly inspect five, one square foot areas per field every week. Spread the leaves and inspect the crowns, leaf bases, leaf stems, and flower stems looking for the frothy spittle masses. Small, yellow-orange nymphs will be under the spittle. If the average number of spittle masses is more than two per 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®.

Diseases: The conditions have been wet enough in most fields to encourage Botrytis infections, which will lead to gray mold once the fruit start to ripen. Two to three sprays of fungicide during bloom are usually required to provide good protection against this disease.

Leather rot (Phytopthora cactorum) is still a concern for fields which have had long periods of standing water during this wet spring, especially if the fields were not mulched last fall. Fungicides applied for gray mold are generally not effective for leather rot. Foliar sprays of Aliette®, Agri-Phos® or Phostrol® applied during bloom or fruit development can help prevent leather rot.

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 symptoms of this fungus disease have just started showing up in fields this week. As the weather warms up expect it to become more prevalent. Mildew may first appear as purple or red streaks on the leaf and flower stems. Later, upward curling leaves and white, powdery growth on the undersides becomes evident. Keep an eye out for leaf cupping in your fields as the days start to get warmer.  Pristine®, Cabrio®, Topsin-M®, captan, Procure®, Torino® and JMS Stylet oil® are registered to control powdery mildew.

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. 2 – May 30, 2014

Friday, May 30th, 2014

StrawberriesStrawberry IPM Newsletter No. 2 – May 30, 2014

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STRAWBERRY PESTS NOW ACTIVE DESPITE COOL, WET WEATHER

Clippers, Tarnished Plant Bugs, Spider Mites Found in Fields this Week

Strawberry Frost Injury

Frost Injury to Flowers and Leaves, Photo By David Handley

Vegetable and Berry Growers Twilight Meeting
Wednesday, June 11, 2014 at 5:30 p.m.
Fairwinds Farm, Bowdoinham, Maine

Situation: Continued cool wet weather has kept strawberry development at a relatively slow pace.  Fields in southern to mid-state Maine are coming into full bloom for early varieties, while late varieties are just starting to show a few primary blossoms.  The time from bloom to harvest is approximately three weeks, but may take a little longer under extended cool conditions.  Most fields we visited this week showed some moderate winter injury.  Weak plants, especially in areas where the mulch was thin, show browning within the crown tissue, indicative of freeze damage.

Twilight Meeting
The University of Maine Cooperative Extension and the Maine Vegetable and Small Fruit Growers Association will hold a twilight meeting at Fairwinds Farm in Bowdoinham on Wednesday, June 11 at 5:30 p.m.  Pete and Cathy Karonis grow 10 acres of strawberries and approximately 40 acres of mixed vegetables in fields along the Kennebec River and have a farm stand and greenhouses in Topsham.  They will host a tour of their strawberry, raspberry and vegetable plantings, and describe their growing and marketing practices.  In addition, we’ll discuss the upcoming season and pest management issues facing vegetable and berry growers this year.  One pesticide applicator recertification credit will be awarded for the meeting. Hold the date! We’ll give driving directions soon.

Strawberry bud weevil or “clipper” is now active in most of the fields we’ve scouted. Damage so far is very light, suggesting that the adults are feeding on pollen and mating, but they will very soon start laying eggs and clipping buds. If you haven’t yet been looking for clipped buds, now is the time. Insecticide options for clipper include Lorsban®, Brigade®, Bifenture®, Danitol®,  Sevin® and PyGanic®.

Clipper Injury

Clipper Injury, Photo by David Handley

Tarnished Plant Bug Nymph on Strawberry Blossom

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

Tarnished plant bug nymphs were found in most of the fields we scouted this week.  The nymphs can be hard to find, especially if the plants are wet. Young nymphs are very small (2 mm), active, yellow-green insects.  It is important to scout for them regularly, as they can appear very quickly. Only one field was over the threshold (4 or more flower clusters infested per 30 sampled). Start scouting any field with open flowers now.  Insecticide options for tarnished plant bug include malathion, Assail®, Brigade®, Bifenture®, Danitol®, and PyGanic®.

Two-spotted Spider Mites

Two-spotted Spider Mites, photo by David Handley

Two-spotted spider mites were over the threshold (25% of leaves infested) in one location this week.  This is surprising given how cold and wet it has been.  Mites typically proliferate under hot, dry conditions, and we often first find them in plantings under row covers.  But plantings that harbored a high mite population last fall are also likely to see a problem with mites in the spring.  Spider mites will reproduce rapidly under warmer temperatures, so it is important to scout for them regularly. 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).

Cyclamen mites:  One two-year old field showed symptoms of cyclamen mite injury this week.  Infested plants show weak growth and yellow, crinkled leaves. These mites are very small 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. Portal®, Kelthane® or Thionex® 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.

Root weevil management
Plants damaged by root weevils should become more obvious in the coming days as the fields dry out and the grubs become more active.  We have not found any additional fields infested since our reports of two fields last week. Infested plants appear weak and stunted, and may wilt during hot days. 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.  Once the adults become active in July, bifenthrin (Brigade®) will provide some control if used at the highest labeled rates.

Diseases: As the fields come into bloom it is time to protect the flowers against infection by spores of the gray mold fungus, Botrytis cinerea. Two to three sprays of fungicide during bloom are typically required to provide good protection against this disease. Remember that fruit infections take place through the flowers, so gray mold control efforts must be focused on the bloom period.

Leather rot (Phytopthora cactorum) may become a problem in fields where standing water is common during bloom and fruit development, especially if the fields were not mulched last fall. Incidence of leather rot can be reduced by applying straw mulch between the rows to prevent berries from touching the soil and reducing soil splashing onto the berries.  Foliar sprays of Aliette®, Agri-Phos® or Phostrol® may be applied during bloom and fruit development to prevent leather rot when there has been excess moisture in a field, especially those with a history of this problem.

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:  We have not yet seen symptoms of this fungus disease in fields.  It tends to be more prevalent under warm, humid conditions. It may first appear as purple or red blotches on the leaf and flower stems. Later, upward curling leaves and white, powdery growth on the undersides of the leaves becomes evident. 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 registered to control powdery mildew.

Angular Leaf Spot

Bacterial Angular Leaf Spot, Photo by David Handley

Angular leaf spot was found in one field this week.  This is a bacterial disease characterized by small water-soaked spots on the leaves, which may turn yellow or black. The symptoms start on the lower leaves but spread throughout the foliage when spores are splashed up by rain or irrigation water. Infections can cause blackening of the berry stems and caps. This disease is favored by extended cool, wet weather with night temperatures close to freezing. Irrigating fields for frost protection encourages development and spread of the disease. 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. 11 – September 6, 2013

Friday, September 6th, 2013

Sweet Corn

Sweet Corn IPM Newsletter No. 11 – September 6, 2013

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

Last Regular Issue for 2013

LATE SILKING CORN STILL NEEDS PROTECTION

Higher Earworm Counts in Southern and Coastal Locations

This will be the final issue of the Sweet Corn IPM Newsletter for the 2013 season. I would like to thank all of the growers who participated in the program this year, and our team of IPM scouts including Kara Rowley, Hayden Koller, Tammy Cushman, Griffin Dill and Sean McAuley, with help from John Hutton. Thanks to Pam St. Peter for getting us to print and keeping up the web page.  Input from our readers is welcome. Please call or e-mail us with your questions, comments and suggestions.

SITUATION
The storm last week appears to have brought some corn earworm moths into the state, as well as several inches of rain. Post Labor Day corn has matured quickly, but the market seems to be holding well, even with a plentiful supply. Insect pressure is relatively low for this late in the summer, especially in more northern and inland sites; although any weather coming up from the tropics over the next few weeks could change that status very quickly.

European corn borer:  Moth catches were fairly low and sporadic this week. A weak second generation appears to be showing up in a few locations, but most sites are well under threshold. Fields in Dayton, North Berwick, Wayne and Wells exceeded the threshold of 5 moths per week in silking corn, but only the Wayne field is not presently under a spray interval for corn earworm.

Corn earworm:  Moth counts were higher in some southern and coastal locations this week, suggesting that the recent storm may have brought in some moths. A 4-day spray interval for fresh silking corn was recommended at one site in Cape Elizabeth. A 5-day spray interval was recommended in Monmouth and the other Cape Elizabeth site. A 6-day spray interval was recommended for silking fields in Biddeford, a Dayton site, New Gloucester, North Berwick, Poland Spring, Sabattus, Warren and one Wells site. Remember that any storm fronts moving up from the south can bring lots of corn earworm with them and change the situation rapidly for any silking corn remaining.

Corn Earworm Larvae

Corn Earworm Larvae, photo by David Handley

Fall Armyworm Injury on Corn Leaves

Fall Armyworm Injury on Corn Leaves, photo by David Handley

Fall armyworm:  Moth counts were higher in some sites this week, but most remain under threshold for silking corn. Fall armyworm exceeded the threshold of three moths for silking corn in Cape Elizabeth, Dayton, Monmouth, New Gloucester, Nobleboro, Oxford, Warren and Wells.

Remember to plow down your corn stalks.
Plowing down corn stalks destroys overwintering sites for European corn borer. Winter rye can be planted after plow down to prevent soil erosion and conserve nutrients.

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 Alert:  Fruit fly counts are increasing significantly this week and we’re getting more reports of larvae in ripening fruit, including fall raspberries, blueberries, blackberries and grapes. All ripening fruit should be protected with regular and repeated treatments of an approved insecticide. In most fields a 4 to 5 day spray interval is needed to prevent infestation.  Visit our website for details:  http://umaine.edu/highmoor/spotted-wing-drosophila/.

The New England Vegetable & Fruit Conference will be held in Manchester, New Hampshire on December 17, 18, and 19, 2013. Program and registration information will be coming soon.  Visit the website: http://www.newenglandvfc.org/.

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
Recommendations / Comments
Auburn 0 0 0 No spray recommended
Biddeford 3 2 1 6-day spray interval recommended on all silking corn
Cape Elizabeth I 4 3 0 5-day spray interval recommended on all silking corn
Cape Elizabeth II 12 0 5 4-day spray interval recommended on all silking corn
Dayton I 1 3 3 One spray recommended for FAW on all silking corn
Dayton II 3 11 1 6-day spray interval recommended on all silking corn
Farmington 0 1 1 No spray recommended
Lewiston 0 3 0 No spray recommended
Monmouth 4 3 3 5-day spray interval recommended on all silking corn
New Gloucester 2 0 3 6-day spray interval recommended on all silking corn
Nobleboro 0 0 6 One spray recommended for FAW on all silking corn
No. Berwick 3 8 0 6-day spray interval recommended on all silking corn
Oxford 0 0 3 One spray recommended for FAW on all silking corn
Poland Spring 2 0 0 6-day spray interval recommended on all silking corn
Sabattus 2 1 1 6-day spray interval recommended on all silking corn
Wales 0 0 2 No spray recommended
Warren 3 2 9 6-day spray interval recommended on all silking corn
Wayne 0 6 0 One spray recommended for ECB on all silking corn
Wells I 0 0 0 No spray recommended
Wells II 2 5 5 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. 10 – August 30, 2013

Tuesday, September 3rd, 2013

Sweet CornSweet Corn IPM Newsletter No. 10 – August 30, 2013

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

LOW CORN PEST PRESSURE FOR LATE SEASON CORN

Higher Fall Armyworm Moth Counts in some Southern and Coastal Locations

SITUATION
Late corn has been maturing quickly in much of the state, under good weather conditions. It looks as though there will be a good supply of high quality corn for the holiday weekend. Insect pests remain fairly quiet this week.  Vertebrate pest problems have been increasing. Many fields have been visited by hungry birds, skunks, raccoons and deer recently. Next week will be the last regular issue of the Sweet Corn IPM Newsletter for the 2013 season.

Corn Harvester

Corn Harvester, photo by David Handley

European Corn Borer Moth

European Corn Borer Moth, photo by David Handley

European corn borer:  Moth catches were up in some locations this week suggesting that a weak second generation of European corn borer may be getting started in southern Maine. These moths could threaten silking corn in fields that are not under a regular spray schedule for corn earworm. Fields in New Gloucester, Nobleboro, North Berwick and Sabattus exceeded the threshold of 5 moths per week in silking corn; but the North Berwick field is under a spray interval for corn earworm, so no additional sprays should be required. Nearly all fields are in silk, so we did not scout for feeding damage this week, but based our recommendations on pheromone trap catches.

Corn earworm:  Moth counts were lower in most locations this week. Most traps caught no moths and therefore no spray intervals were recommended this week for silking corn at those sites. A 5-day spray interval was recommended for fields in one of the Dayton sites and Charleston this week. A 6-day spray interval was recommended for silking fields in Auburn, a Dayton site and North Berwick. While the relatively light pressure has meant a relaxed spray schedule for many growers this season, remember that any storm fronts that move up the coast from the south in the coming days and weeks could bring lots of corn earworm with them and change the situation rapidly for any silking corn.

Fall armyworm:  Moth counts were higher in some southern and coastal sites, but most caught few or no moths this week. Fall armyworm exceeded the weekly threshold of three moths for silking corn in Biddeford, Cape Elizabeth, Dayton, Monmouth, Nobleboro, Warren and Wells.

Male Fall Armyworm Moth

Male Fall Armyworm Moth, photo by David Handley

Spotted Wing Drosophila on Raspberry

SWD on Raspberry, photo by David Handley.

Spotted Wing Drosophila Alert:  Fruit fly counts are increasing at many sites this week, and more sites are now catching flies. We have more grower reports of larvae in fruit, indicating that even low trap captures signal a significant threat. We recommend that all ripening fruit be protected with an approved insecticide. Regular and repeated treatments are needed to keep fruit from becoming infested. In some locations a 7-day spray interval has not been adequate to prevent infestation, so we have tightened the spray schedule to 4 to 5 days. Chilling fruit to as close to 32ºF immediately after harvest can significantly reduce the activity and emergence of any larvae. Visit our Spotted Wing Drosophila blog for more details.

Understanding and Managing Soils for Healthy Productive Crops: This series will offer farmers strategies to successfully manage soils for long-term productivity. It will take place on Tuesdays, 6:00 PM to 8:00 PM on October 1, 8, 15, 22 and 29, at the Knox and Lincoln Counties Cooperative Extension Office, 377 Manktown Road, Waldoboro, Maine. Cost is $40 per person for the series, or $10 per session. Contact Mark Hutchinson at 207.832.0343 or mhutch@maine.edu for more information, or visit the UMaine Cooperative Extension Agriculture Programs 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
Recommendations / Comments
Auburn 2 0 0 6-day spray interval recommended on all silking corn
Biddeford 0 0 10 One spray recommended for FAW on all silking corn
Cape Elizabeth I 1 0 10 One spray recommended for FAW on all silking corn
Cape Elizabeth II 1 3 7 One spray recommended for FAW on all silking corn
Charleston 4 1 1 5-day spray interval recommended on all silking corn
Dayton I 2 3 3 6-day spray interval recommended on all silking corn
Dayton II 4 2 0 5-day spray interval recommended on all silking corn
Farmington 0 4 0 No spray recommended
Garland 0 3 1 No spray recommended
Levant 0 2 0 No spray recommended
Lewiston 0 0 No spray recommended
Monmouth 1 1 3 One spray recommended for FAW on all silking corn
New Gloucester 1 7 One spray recommended for ECB on all silking corn
Nobleboro 0 6 4 One spray recommended for FAW+ECB on all silking corn
No. Berwick 3 6 6-day spray interval recommended on all silking corn
Oxford 0 1 0 No spray recommended
Palmyra 0 1 0 No spray recommended
Sabattus 0 6 2 One spray recommended for ECB on all silking corn
Wales 0 1 1 No spray recommended
Warren 0 1 11 One spray recommended for FAW on all silking corn
Wayne 0 2 0 No spray recommended
Wells I 0 0 0 No spray recommended
Wells II 1 3 7 One spray recommended for FAW 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. 9 – August 23, 2013

Friday, August 23rd, 2013

Sweet Corn Sweet Corn IPM Newsletter No. 9 – August 23, 2013

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

CORN PEST PRESSURE INCREASING IN SOUTHERN AND COASTAL REGIONS

Higher Moth Counts Require Tighter Spray Schedule for Silking Corn

SITUATION
A stretch of nice weather has been good for corn growth, but also appears to have allowed corn pests to build up in southern and coastal sites. Pest pressure is fairly light for this late in the season, however, as the tropical storm activity that often brings corn pests into the state late in the summer has been very quiet.

European corn borer:  Moth catches were very low again this week, with the exception of a couple of northern sites. Fields in Nobleboro and Levant exceeded the threshold of 5 moths per week in silking corn, but the Nobleboro field is under a spray interval for corn earworm, so no additional sprays should be required. No fields had European corn borer feeding damage over threshold.

Corn earworm:  Moth counts are rising in some southern and coastal locations, although many locations still had no moths in pheromone traps this week and do not require a spray interval for silking corn at this time.  A 4-day spray interval was recommended for silking corn in Biddeford and one Cape Elizabeth site.  A 5-day spray interval was recommended for fields in Auburn, Dayton and Nobleboro, Warren and one Wells site. A 6-day spray interval was recommended for silking fields in Lewiston, Monmouth and New Gloucester.

Corn Earworm Moth

Corn Earworm Moth, photo by David Handley

Adult Fall Armyworm

Adult Fall Armyworm, photo by David Handley

Fall armyworm:  Moth counts have increased in some southern and coastal sites, but many sites caught no moths this week. Fall armyworm moths were caught in Biddeford, Cape Elizabeth, Dayton, Livermore Falls, Monmouth, North Berwick, Oxford, Warren and one Wells site. The Biddeford, Cape Elizabeth, Monmouth, North Berwick, Oxford and Warren sites exceeded the weekly threshold of three moths for silking corn. Fall armyworm feeding damage on younger corn exceeded the spray threshold of 15% only at the Biddeford site.

Spotted Wing Drosophila Larvae in Raspberry

Spotted Wing Drosophila Larvae in Raspberry, photo by David Handley

Spotted Wing Drosophila Alert:  Fruit fly counts remain quite variable around the state. We found high numbers (100+) of flies at two sites, Limington and New Gloucester, and this may be related to lower availability of fruit at these sites, as summer raspberries are now pretty much gone. Most other sites had fewer than 4 flies for the week and many sites had none. At this point however, we recommend that all ripening fruit be protected with a recommended insecticide. Regular and repeated treatments are needed to keep fruit from becoming infested. Visit our Spotted Wing Drosophila blog for more details.

Free Disposal of Banned, Unusable Pesticides:  Farmers are urged to take advantage of a free opportunity to dispose of banned or unusable pesticides that they may have on their properties. This October, the Maine Board of Pesticides Control (BPC) and the Maine Department of Environmental Protection will dispose of banned pesticides or pesticides that have become caked, frozen, or otherwise rendered unusable. This free disposal program is open to homeowners, family-owned farms and greenhouses. All people need to do is register by September 27, 2013. Registration is mandatory; drop-ins are not permitted. To register and get more information on this program and pesticide disposal, go to the BPC website at:  www.thinkfirstspraylast.org, or call 207.287.2731.

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 5 0 0 5-day spray interval recommended on all silking corn
Biddeford 8 0 15 15% 4-day spray interval recommended on all silking corn
Cape Elizabeth I 11 0 7 5% 4-day spray interval recommended on all silking corn
Cape Elizabeth II 1 0 16 7% One spray recommended for FAW on all silking corn
Dayton I 6 2 1 3% 5-day spray interval recommended on all silking corn
Farmington 0 2 0 0% No spray recommended
Garland 0 2 0 1% No spray recommended
Levant 0 6 0 4% One spray recommended for ECB on all silking corn
Lewiston 2 2 0 0% 6-day spray interval recommended on all silking corn
Livermore Falls 0 0 1 6% No spray recommended
Monmouth 2 0 8 6-day spray interval recommended on all silking corn
New Gloucester 3 1 0 2% 6-day spray interval recommended on all silking corn
Nobleboro 4 6 0 5-day spray interval recommended on all silking corn
No. Berwick 0 0 13 3% One spray recommended for ECB on all silking corn
Oxford 1 0 3 One spray recommended for FAW on all silking corn
Palmyra 0 4 0 3% No spray recommended
Poland Spring 1 1 0 5% No spray recommended
Sabattus 1 0 0 10% No spray recommended
Warren 7 1 4 5-day spray interval recommended on all silking corn
Wells I 0 0 0 7% No spray recommended
Wells II 6 0 1 0% 5-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. 8 – August 16, 2013

Friday, August 16th, 2013

Sweet Corn

Sweet Corn IPM Newsletter No. 8 – August 16, 2013

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

ANOTHER WEEK OF LOW PEST PRESSURE

Moth Counts and Feeding Injury under Spray Thresholds in Most Corn Fields

SITUATION
Our weather continues to be dominated by fronts coming from the west and northwest, which appears to be keeping corn earworm and fall army worm moths from moving into Maine from the south in high numbers.  Most farms continue to enjoy a light spray schedule for this time of the season.

European corn borer:  Moth catches were very low again this week. In some years we may start to see a second generation of European corn borer moths emerge in the late summer, but there has been no indication of that so far this season. No silking fields exceeded the threshold of 5 moths per week. No fields had European corn borer feeding damage over threshold.

Corn earworm:  Moth counts fell slightly to even lower levels than last week in most locations. Many fields do not require a spray interval for silking corn at this time.  A 5-day spray interval was recommended for fields in Monmouth and Charleston. A 6-day spray interval was recommended for silking fields in Cape Elizabeth, Garland, Levant, North Berwick and Wales.

Fall armyworm:  Moth counts are very low for this late in the season. Fall armyworm moths were caught in Biddeford, Cape Elizabeth, one Dayton site, Levant, Lewiston and Wells this week. Only the Biddeford and Dayton sites exceeded the weekly threshold of three moths for silking corn. Sites in Biddeford and Cape Elizabeth had fall armyworm feeding damage on younger corn exceeding the spray threshold of 15%.

Fall Armyworm on Corn Silk

Fall Armyworm on Corn Silk, photo by David Handley

Aphids on Corn Tassel

Aphids on Corn Tassel, photo by Kaytlin Woodman

Aphids:  Some fields are showing infestations of aphids on corn tassels, silks and husks. While aphid feeding is not usually a significant problem, the sooty mold that develops on the husks as a result of their waste (called honeydew), is often objectionable to customers.  Sprays, other than Bt’s or spinosad products, that are used to control other corn pests also offer control of aphids, including Asana®, Capture®, Warrior® and Lannate®.

Late Blight on Tomato Leaf

Late Blight on Tomato Leaf, photo by James Dill

Late Blight:  Grower and Farm Stand Alert
Late blight has been found on tomato plants in coastal Maine (Warren) this week. This follows reports of late blight in tomato and potato plantings in Vermont and New York. Growers should be alert to catch early symptoms and be ready to apply appropriate control measures.  Symptoms include water-soaked lesions on the leaves with fine, white cottony mycelium on the undersides. Infections on the stems appear as dark, almost black lesions. Please report any suspicious symptoms to the Pest Management Office at 581-3883, or email PMO@umext.maine.edu.

Spotted Wing Drosophila Alert
Fruit fly counts are still variable around the state, but we are catching flies at most locations now, including Limington, Springvale, Wells, Cape Elizabeth, New Gloucester, Gray, Monmouth, Wales, Livermore Falls, Bowdoinham, Dresden and Warren.  Most traps had fewer than ten flies. The exception was, again, our Bowdoinham site, which had over 100 flies. Once spotted wing drosophila is found in your area, fruit should be protected with a recommended insecticide.  Regular and repeated treatments are needed to keep fruit from becoming infested. Visit our Spotted Wing Drosophila blog for more details.

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 1 0 2% No spray recommended
Biddeford 0 1 6 16% One spray recommended for FAW
Cape Elizabeth 2 2 2 26% 6-day spray interval recommended on all silking corn
Charleston 6 0 0 2% 5-day spray interval recommended on all silking corn
Dayton I 0 0 6 3% One spray recommended for FAW
Dayton II 0 0 0 1% No spray recommended
Farmington 0 0 0 0% No spray recommended
Garland 3 1 0 3% 6-day spray interval recommended on all silking corn
Levant 3 1 1 3% 6-day spray interval recommended on all silking corn
Lewiston 0 0 1 1% No spray recommended
Monmouth 5 0 2 1% 5-day spray interval recommended on all silking corn
New Gloucester 1 2 0 1% No spray recommended
Nobleboro 1 1 0 12% No spray recommended
No. Berwick 2 1 0 3% 6-day spray interval recommended on all silking corn
Palmyra 0 1 0 4% No spray recommended
Sabattus 0 0 0 0% No spray recommended
Wales 2 0 0 6-day spray interval recommended on all silking corn
Warren 1 0 0 5% No spray recommended
Wells 0 0 1 8% 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 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. 7 – August 9, 2013

Friday, August 9th, 2013

Sweet CornSweet Corn IPM Newsletter No. 7 – August 9, 2013

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

CORN PEST PRESSURE REMAINS LIGHT IN MOST FIELDS

Corn Earworm, Fall Armyworm & European Corn Borer Damage Low

SITUATION
Another week of fairly light insect pressure in most locations this week, thanks to a relatively stable weather pattern. Storm fronts coming across from the Midwest or the South could quickly bring higher moth counts to the state, but for now most farms are enjoying a light spray schedule for this time of the season.

European corn borer: Moth catches were very low across the state this week. No silking fields exceeded the threshold of 5 moths per week. European corn borer feeding damage was over threshold in a pre-tassel field in Oxford this week. When European corn borer and fall armyworm damage are found in the same field, the damage is combined and the spray threshold is lowered to 12% injury. This week a field in Sabattus exceeded the combined injury level.

Corn earworm: Moth counts continued to be low in all locations this week and many fields required no additional protection. A 5-day spray interval was recommended for one site in Cape Elizabeth, Charleston, one site in Dayton, and New Gloucester. A 6-day spray interval was recommended for silking fields in Biddeford, Garland, and Nobleboro.

European Corn Borer Entry Hole

European Corn Borer Entry Hole, photo by David Handley

Fall Armyworm Eggs on Corn

Fall Armyworm Eggs on Corn, photo by David Handley

Fall armyworm: Most sites have still not seen significant fall armyworm damage this season. Fall armyworm moths were caught only in Biddeford, one Dayton site and in Nobleboro this week. Biddeford and Dayton exceeded the weekly threshold of three moths for silking corn. A single moth was caught in Nobleboro. Our site in Biddeford was the only location where fall armyworm feeding damage on younger corn exceeded the spray threshold.

Squash vine borer: Moth counts continued to drop this week. Squash vine borers were caught in Cape Elizabeth and Dayton, but the threshold of five moths per week was not exceeded at either of these locations.

Plectosporium blight: Symptoms of Plectosporium have also been found in pumpkin fields over the past two weeks. This fungus disease causes white flecking in the surface of the fruit and leaves, leading to collapse of the plants and fruit rot. See the New England Vegetable Management Guide for details. The fungicides Quadris®, Maneb®, Bravo®, Cabrio® and Flint® are labeled for use on pumpkins to control Plectosporium.

Plectosporium blight on pumpkin

Plectosporium blight on pumpkin, photo by Mark Hutton

Male Spotted Wing Drosophila

Male Spotted Wing Drosophila, photo by Griffin Dill. Actual size: 2-3 mm.

Spotted Wing Drosophila Alert: Fruit fly counts were quite variable this week, with some sights catching few or no flies while one had the highest count of the season. Flies were caught in Wells, Cape Elizabeth, Limington, New Gloucester, Gray, Monmouth, Bowdoinham and Corinna. Most traps had one to three flies in them. The exception was the Bowdoinham site, which had over 200 flies for the week. The tiny larvae of these flies can quickly destroy ripening soft fruit such as raspberries and blueberries. Once spotted wing drosophila is found in your area, fruit should be protected with a recommended insecticide. Regular and repeated treatments are usually needed to keep fruit from becoming infested. Visit our Spotted Wing Drosophila blog for more details.

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 0 0 6% No spray recommended
Biddeford 3 0 5 19% 6-day spray interval recommended on all silking corn
Cape Elizabeth I 0 0 0 3% No spray recommended
Cape Elizabeth II 5 0 0 5-day spray interval recommended on all silking corn
Charleston 4 3 0 0% 5-day spray interval recommended on all silking corn
Dayton I 6 1 6 7% 5-day spray interval recommended on all silking corn
Dayton II 0 1 0 8% No spray recommended
Farmington 0 0 0 0% No spray recommended
Garland 3 0 0 0% 6-day spray interval recommended on all silking corn
Levant 0 1 0 3% No spray recommended
Lewiston 0 0 0 0% No spray recommended
Livermore Falls 0 0 0 3% No spray recommended
Monmouth 0 0 No spray recommended
New Gloucester 7 3 0 5-day spray interval recommended on all silking corn
Nobleboro 2 0 1 5% 6-day spray interval recommended on all silking corn
No. Berwick 1 0 0 2% No spray recommended
Oxford 0 1 0 24% One spray recommended for ECB feeding
Palmyra 0 0 0 2% No spray recommended
Poland Spring 0 0 0 7% No spray recommended
Sabattus 0 0 0 18% One spray recommended for ECB+FAW feeding
Wales 0 0 0 5% No spray recommended
Warren 0 0 0 2% No spray recommended
Wells I 1 0 0 2% No spray recommended
Wells II 0 0 0 1% 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.

Sweet Corn IPM Newsletter No. 6 – August 2, 2013

Friday, August 2nd, 2013

Sweet CornSweet Corn IPM Newsletter No. 6 – August 2, 2013

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

A FAIRLY QUIET WEEK FOR CORN PESTS

Corn Earworm, Fall Armyworm & European Corn Borer Pressure Remains Light

SITUATION
Weather patterns continue to keep insect pressure fairly light in most locations. Harvest continues to look good, although maturity and supply has been spotty. Keep an eye out for late season diseases, especially corn rust, in younger fields.

European corn borer:  Moth catches in southern Maine were low again this week. Only silking fields in New Gloucester, Charleston and Palmyra were over the threshold of 5 moths per week, but the Charleston site is on a spray schedule for corn earworm, so no additional sprays were required. European corn borer feeding damage was over threshold in a pre-tassel field in Oxford this week. When European corn borer and fall armyworm damage are found in the same field, the damage is combined and the spray threshold is lowered to 12% injury. This week a field in Biddeford exceeded the combined injury level.

European Corn Borer Larva on Ear

European Corn Borer Larva on Ear, photo by David Handley

Corn Earworm Feeding on Corn

Corn Earworm Feeding on Corn, photo by David Handley

Corn earworm:  Moth counts are low in all locations this week and most locations did not require protection. A 5-day spray interval was recommended for Charleston and one site in Dayton. A 6-day spray interval was recommended for silking fields in the other Dayton site, as well as Garland, Sabattus and Warren.

Fall armyworm:  Most sites had few or no fall armyworm moths in pheromone traps this week. The exception was Monmouth, where 5 moths were caught; exceeding the weekly threshold of three for silking corn. This is a late field with no silk yet. Single moths were caught in Biddeford, Dayton and Levant.  Very little fall armyworm feeding damage was found in younger corn fields.

Squash vine borer:  Moth counts were down significantly this week. Squash vine borers were caught in North Berwick, Wells, Dayton, Biddeford and Gray, but the threshold of five moths per week was not exceeded at any of these locations. This pest will likely only have one generation per year in Maine, although a late, partial second generation is possible.

Potato Leafhopper Alert:  Potato leafhopper feeding is showing up in vegetable and berry fields this week. Leafhoppers are small, bullet-shaped insects that feed on plant sap, causing the leaves to become curled, stunted and yellow-streaked. Beans are quite susceptible to the injury, in addition to potatoes and strawberries. The small, whitish leafhoppers adults can be seen flying off the plants when disturbed. The small, (1/16 inch) light green leafhopper nymphs are found on the underside of injured leaves.  Control options are listed in the New England Vegetable Management Guide.

Potato Leafhopper

Potato Leafhopper, photo by James Dill

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 Alert:  Captures of the fruit fly were fairly low this week, indicating that the population has not started its exponential growth yet. Flies were caught in Wells, New Gloucester, Dresden and Bowdoinham. The larvae of these flies can quickly destroy any soft fruit such as raspberries and blueberries. When spotted wing drosophila is found in your area, ripening fruit should be protected with a recommended insecticide. Regular and repeated treatments are usually needed to keep fruit from becoming infested. Visit our Spotted Wing Drosophila blog for more details.

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 0 0 0% No spray recommended
Biddeford 1 1 1 14% One spray recommended for ECB + FAW feeding
Cape Elizabeth I 0 0 0 5% No spray recommended
Cape Elizabeth II 0 6 0 One spray recommended on silking corn for ECB
Charleston 7 17 0 3% 5-day spray interval recommended on all silking corn
Dayton I 3 3 0 0% 6-day spray interval recommended on all silking corn
Dayton II 4 1 1 2% 5-day spray interval recommended on all silking corn
Farmington 0 0 0 0% No spray recommended
Garland 3 3 0 1% 6-day spray interval recommended on all silking corn
Gray 0 4 0 0% No spray recommended
Levant 0 5 1 2% One spray recommended on silking corn for ECB
Lewiston 0 1 0 7% No spray recommended
Livermore Falls 0 0 0 No spray recommended
Monmouth 0 3 5 5% No spray recommended (no silking corn)
New Gloucester 1 12 0 0% One spray recommended on silking corn for ECB
No. Berwick 0 0 0 0% No spray recommended
Oxford 0 0 0 19% One spray recommended for ECB feeding
Palmyra 0 18 0 6% One spray recommended on silking corn for ECB
Sabattus 2 5 0 3% 6-day spray interval recommended on all silking corn
Wales 0 1 0 0% No spray recommended
Warren 2 1 0 7% 6-day spray interval recommended on all silking corn
Wells I 0 0 0 4% 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.