Posts Tagged ‘corn’

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.

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.

Sweet Corn IPM Newsletter No. 12 – August 29, 2012

Wednesday, August 29th, 2012

Sweet Corn

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

CORN EARWORM PRESSURE LOWER UNDER COOL NIGHTS

Fall Armyworm and European Corn Borer Numbers Remain Low

SITUATION
Recent relatively cool nights indicate a shift in the weather pattern and have resulted in a dramatic drop in corn earworm captures this week.  However, populations are still high enough to keep all silking fields on a regular spray schedule.  As we approach Labor Day and the season starts to wind down, we have very little pressure from either fall armyworm or European corn borer.  Hot weather predicted for the remainder of the week will push remaining corn maturity along rapidly.  Remnants of hurricane Isaac may visit Maine next week and could bring with it a new flush of earworm and armyworm.

European corn borer:  Moth counts are very low this week with no sites exceeding the 5-moth threshold for silking corn.  Feeding damage was also low, with only the North Berwick site exceeding the 15% threshold when it was combined with fall armyworm damage.

Corn earworm:  Moth counts were significantly lower in all locations this week, but pressure still remains moderate to high for many locations.  A 3-day spray interval for fresh silking corn was recommended only for North Berwick.  A 4-day spray interval was recommended for Biddeford, one Cape Elizabeth location, Dayton, Dresden, East Corinth, Levant, Lewiston, Monmouth, Wales, Wayne and one Wells location.  A 5-day spray interval was recommended for one Cape Elizabeth location, New Gloucester, Nobleboro, Oxford, and one Wells location.  A 6-day spray interval was recommended for Charleston, Jefferson, Palmyra, Poland Spring, and Warren.

Corn Earworm Larvae

Corn Earworm Larvae, photo by David Handley

Fall armyworm:  We continue to find light feeding damage in some fields, but only North Berwick was over the threshold when combined with ECB feeding damage.  Moth captures continue to be very low for this time of year, with no sites exceeding the spray threshold of 3 moths in silking corn.  Two fall armyworm moths were caught at Cape Elizabeth, and one Lewiston location, and single moths were caught in Biddeford, Cape Elizabeth, Dresden, East Corinth, New Gloucester, and Warren.  Fall armyworm feeding damage was found in Biddeford, Cape Elizabeth and New Gloucester, but was below the 15% threshold.  Most remaining fields are silking and under a spray schedule for corn earworm, so field scouting is not necessary.

Fall Armyworm on Corn Silk

Fall Armyworm on Corn Silk, photo by David Handley

Spotted Wing Drosophila Update:
Over the last week spotted wing drosophila numbers have risen significantly. Flies are now at their highest levels of the season.  We have also found drosophila maggots infesting blueberry, raspberry, blackberry, elderberry, grape and peach fruit this week.  For those with late fruit crops still to harvest, protection is necessary to prevent infestation by spotted wing drosophila.  Up to this point weekly applications of an allowed insecticide have been adequate, but reports from the field suggest that more frequent applications may be necessary to keep fruit free from maggots.  Growers in southern states have found that a 3 to 5-day spray schedule was needed to prevent infestation.

Spotted Wing Drosophila Larva in Blueberry

Spotted Wing Drosophila Larvae in Blueberry, photo by David Handley

 

Spotted Wing Drosophila Larvae in Raspberry

Spotted Wing Drosophila Larvae in Raspberry, photo by David Handley

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 8 1 1 6% 4-day spray interval for all silking corn
Cape Elizabeth I 9 0 2 All silking 4-day spray interval for all silking corn
Cape Elizabeth II 7 0 1 5% 5-day spray interval for all silking corn
Charleston 2 1 0 1% 6-day spray interval for all silking corn
Dayton I 33 0 0 All silking 4-day spray interval for all silking corn
Dayton II 15 0 0 All silking 4-day spray interval for all silking corn
Dresden 32 0 1 All silking 4-day spray interval for all silking corn
East Corinth 16 0 1 0% 4-day spray interval for all silking corn
Jefferson 3 0 0 All silking 6-day spray interval for all silking corn
Levant 11 0 0 2% 4-day spray interval for all silking corn
Lewiston I 47 0 2 All silking 4-day spray interval for all silking corn
Lewiston II 11 1 0 0% 4-day spray interval for all silking corn
Monmouth 40 0 0 All silking 4-day spray interval for all silking corn
New Gloucester 5 0 1 2% 5-day spray interval for all silking corn
Nobleboro 5 0 0 All silking 5-day spray interval for all silking corn
No. Berwick 129 0 0 18% 3-day spray interval for all silking corn
Oxford 5 0 0 All silking 5-day spray interval for all silking corn
Palmyra 2 0 0 All silking 6-day spray interval for all silking corn
Poland Spring 2 0 0 All silking 6-day spray interval for all silking corn
Wales 20 0 0 All silking 4-day spray interval for all silking corn
Warren 2 0 1 All silking 6-day spray interval for all silking corn
Wayne 18 0 0 All silking 4-day spray interval for all silking corn
Wells I 9 0 0 All silking 4-day spray interval for all silking corn
Wells II 6 1 0 All silking 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. 11 – August 22, 2012

Wednesday, August 22nd, 2012

Sweet Corn

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

CORN EARWORM PRESSURE CONSISTENTLY HIGH ACROSS STATE

Fall Armyworm and ECB Pressure Present, but Remains Low

SITUATION
With continued southerly weather and thunderstorms passing through the state, insect pressure has remained high, mostly due to corn earworm.  At this point, every location is on at least a 4-day spray interval, with some locations on 3-day intervals.  For many growers, the youngest corn has reached the silking stage as the corn season begins to come to a close.  Warm weather will continue to help corn mature rapidly and insect pressure will likely remain relatively high.

European corn borer:  Insect counts have decreased, with only two locations over the 5-moth threshold:  Biddeford and Charleston.  Feeding damage from ECB in whorl to tassel stage corn has been present in all fields scouted, but exceeded the 15% threshold in only two locations (Biddeford and Sabattus) when fall armyworm damage was added to the total.

European Corn Borer Larvae on Ear

European Corn Borer Larva on Ear, photo by David Handley

Corn earworm:  Moth counts remain high in all locations, putting very high pressure on all silking corn.  A 3-day spray interval for fresh silking corn was recommended for Biddeford, one Cape Elizabeth location, Dayton, one Lewiston location, and Sabattus.  A 4-day spray interval was recommended in one Cape Elizabeth location, Charleston, East Corinth, Farmington, Jefferson, Levant, Livermore Falls, Monmouth, New Gloucester, Nobleboro, Oxford, Palmyra, Poland Spring, Wales, Warren, and Wells.  No locations had a moth count low enough for a 5- or 6-day spray interval.

Corn Earworm Feeding on Corn

Corn Earworm Feeding on Corn, photo by David Handley

Fall armyworm:  We continue to find feeding damage in southern fields, but only Biddeford and Sabattus were over the threshold when combined with ECB feeding damage.  Moth captures remain low for this time of year, with only one Cape Elizabeth location exceeding the spray threshold of 3 moths in silking corn; but the field is already under a spray schedule for corn earworm so no additional sprays should be needed.  Two fall armyworm moths were caught at Monmouth and Sabattus, and a single moth was caught in Biddeford, Cape Elizabeth, and one Dayton location this week, below threshold for silking corn.  Fall armyworm feeding damage was also found in Cape Elizabeth, New Gloucester, and North Berwick, but was below the 15% threshold.

Fall Armyworm Injury on Corn Leaves

Fall Armyworm Injury on Corn Leaves, photo by David Handley

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

Aphids on Corn

Aphids on Corn, photo by Kaytlin Woodman

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

Highmoor Farm                      Pest Management Office
P.O. Box 179                          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 95 10 1 15% 3-day spray interval for all silking corn
Cape Elizabeth I 162 3 1 All Silk 3-day spray interval for all silking corn
Cape Elizabeth II 85 4 11 6% 4-day spray interval for all silking corn
Charleston 11 5 0 4% 4-day spray interval for all silking corn
Dayton I 118 1 0 All Silk 3-day spray interval for all silking corn
Dayton II 113 0 1 All Silk 3-day spray interval for all silking corn
East Corinth 21 0 0 2% 4-day spray interval for all silking corn
Farmington 14 0 0 All Silk 4-day spray interval for all silking corn
Jefferson 44 0 0 All Silk 4-day spray interval for all silking corn
Levant 54 3 0 6% 4-day spray interval for all silking corn
Lewiston 152 0 0 All Silk 3-day spray interval for all silking corn
Livermore Falls 29 0 0 3% 4-day spray interval for all silking corn
Monmouth 71 0 2 All Silk 4-day spray interval for all silking corn
New Gloucester 30 0 0 9% 4-day spray interval for all silking corn
Nobleboro 20 2 0 1% 4-day spray interval for all silking corn
Oxford 50 0 0 All Silk 4-day spray interval for all silking corn
Palmyra 8 0 0 4% 4-day spray interval for all silking corn
Poland Spring 29 1 0 All Silk 4-day spray interval for all silking corn
Sabattus 145 2 2 16% 3-day spray interval for all silking corn
Wales 16 0 0 3% 4-day spray interval for all silking corn
Warren 83 2 0 All Silk 4-day spray interval for all silking corn
Wells I 50 0 0 All Silk 4-day spray interval for all silking corn
Wells II 89 3 0 All Silk 4-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. 10 – August 15, 2012

Wednesday, August 15th, 2012

Sweet Corn

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

HIGHEST CORN EARWORM COUNTS OF THE SEASON

Fall Armyworm Feeding Observed in Southern Maine

SITUATION
Warm weather has pushed corn maturity along rapidly and supplies are picking up.  A steady flow of weather from the south, including some heavy showers in some areas, is keeping corn earworm pressure very high in most fields this week.  Several locations are now on a recommended 3-day spray interval, which we don’t typically see until early fall when tropical storms start moving through Maine.

European corn borer:  A jump in moth counts in southern Maine suggests an emergence of a second generation of corn borer in that area.  High counts continue to be found in more northern locations as well.  These moths pose a risk to any silking corn that is not presently being sprayed for corn earworm.  Wells, Biddeford, Sabattus, Charleston, Levant, Palmyra, and East Corinth were over the threshold of 5 moths in silking corn.  Feeding injury from larvae in whorl to tassel stage corn was low in most locations, with only Biddeford exceeding the 15% feeding injury threshold.  North Berwick exceeded the threshold when fall armyworm damage was added to the total.

European Corn Borer Entry Hole

European Corn Borer Entry Hole, photo by David Handley

Corn earworm:  Moth counts continue to increase in most locations, putting very high pressure on all silking corn.  A 3-day spray interval for fresh silking corn was recommended for Biddeford, North Berwick, and Wells this week.  A 4-day spray interval was recommended in Cape Elizabeth, Dayton, Dresden, Levant, Lewiston, Monmouth, Palmyra, Poland Spring, Sabattus, and Warren.  A 5-day spray interval was recommended for New Gloucester, East Corinth and Livermore Falls.  A 6-day spray interval was recommended for fields in Charleston and Wales.

Corn Earworm Larvae

Corn Earworm Larvae, photo by David Handley

Fall armyworm:  Moth captures remain low for this time of year, although we have started finding larval feeding damage in some southern fields.  Only one Cape Elizabeth location exceeded the spray threshold of 3 moths in silking corn, but the field is already under a spray schedule for corn earworm so no additional sprays should be needed.  Two fall armyworm moths were caught at Biddeford and our Dayton locations, and a single moth was caught in Dresden this week, below threshold for silking corn.  Fall armyworm feeding damage was found in Biddeford, Dayton, and North Berwick, but was below the 15% threshold.

Fall Armyworm on Corn Leaf

Fall Armyworm on Corn Leaf, photo by David Handley

Other Pests of Note:
Picnic beetles can become a problem during the late summer on silking corn.  These beetles are about ¼ inch long, black with orange spots.  They can often be found on stalks and ears that are infested with European corn borer or fall armyworm, feeding on sap at an entry or exit hole.  They will also feed on the silks and may work their way into the silk channel.  While the damage is usually insignificant, customers dislike finding the insects in their bags.  Sprays to control corn earworm should provide control of these beetles if they are found in your field.

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 97 25 2 39% 3-day spray interval for all silking corn
Cape Elizabeth I 36 2 0 0% 4-day spray interval for all silking corn
Cape Elizabeth II 70 0 3 0% 4-day spray interval for all silking corn
Charleston 3 12 0 4% 6-day spray interval for all silking corn
Dayton I 16 2 0 6% 4-day spray interval for all silking corn
Dayton II 34 1 2 10% 4-day spray interval for all silking corn
Dresden 14 0 1 5% 4-day spray interval for all silking corn
East Corinth 6 0 0 3% 5-day spray interval for all silking corn
Farmington 0 1 0 3% No spray recommended
Levant 31 11 0 13% 4-day spray interval for all silking corn
Lewiston 11 4 0 2% 4-day spray interval for all silking corn
Livermore Falls 7 0 0 6% 5-day spray interval for all silking corn
Monmouth 8 0 0 6% 4-day spray interval for all silking corn
New Gloucester 6 0 0 0% 5-day spray interval for all silking corn
North Berwick 172 4 0 17% 3-day spray interval for all silking corn
Palmyra 11 6 0 5% 4-day spray interval for all silking corn
Poland Spring 45 1 0 All Silk 4-day spray interval for all silking corn
Sabattus 8 10 0 4% 4-day spray interval for all silking corn
Wales 2 0 0 0% 6-day spray interval for all silking corn
Warren 38 1 0 10% 4-day spray interval for all silking corn
Wells I 107 1 0 All Silk 3-day spray interval for all silking corn
Wells II 92 5 0 All Silk 3-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. 9 – August 8, 2012

Thursday, August 9th, 2012

Sweet Corn

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

CORN EARWORM PUTS MOST LOCATIONS ON SPRAY SCHEDULE

Fall Armyworm Pressure Slowly Increasing

SITUATION
Corn harvest is in full swing across most of the state after the warm weekend weather.  Insect pressure has increased, especially from corn earworm with many locations being placed on 4-day spray intervals.  ECB pressure has remained low with the exception of a few northern locations, and fall armyworm appears to be slightly on the rise, but hasn’t exceeded thresholds anywhere.  With the prospect of southerly thunderstorms throughout most of the next week, insect pressure is not expected to decrease.

European corn borer:  Moth counts were still high in a few northern locations this week, requiring protection of silking corn, though only one location wasn’t already protecting against corn earworm.  Counts remained low in most southern fields.  Biddeford, Charleston, Levant, Palmyra, Wells and East Corinth were over the threshold of 5 moths in silking corn.  Feeding injury from larvae in whorl to tassel stage corn remained low in all locations this week, not exceeding the 15% feeding injury threshold in any locations.

European Corn Borer Larvae on Pre-tassel Stage Corn

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

Corn earworm:  Continued pressure from corn earworm has resulted in spray recommendations at all but 3 locations.  A 4-day spray interval was recommended in Biddeford, Cape Elizabeth, Dayton, Dresden, Levant, one Lewiston location, New Gloucester, Nobleboro, North Berwick, Oxford, and Wells.  A 5-day spray interval was recommended for Jefferson, Lewiston, Monmouth, Palmyra, Poland Spring, Sabattus, and Warren.  A 6-day spray interval was recommended for fields in Charleston and Livermore Falls.  Fields in Farmington and Wales caught single moths, which does not warrant a spray.

Corn Earworm

Corn Earworm, photo by David Handley

Fall armyworm:  Moth captures of fall armyworm are increasing.  When scouting, a spray is recommended if feeding injury exceeds 15% of plants in a pre-silking field.  However, larvae may also move into the ears through the silk channel, behaving similarly to corn earworm.  Pheromone trap catches of 3 or more moths per week indicate a spray is needed to protect silking corn, unless it is already under a spray schedule for corn earworm.  Two fall armyworm moths were caught at each Cape Elizabeth location, both Dayton locations, and a single moth was caught at each Wells location this week.  This is below threshold for silking corn.  No feeding damage was found.

Fall Armyworm Eggs on Corn

Fall Armyworm Eggs on Corn, photo by David Handley

Other Pests of Note:
Corn smut is often observed in fields this time of year.  This fungus disease is easily recognized by the large galls which form in the ears, tassels, and on leaves.  The young galls are silvery-white in color.  When the galls mature they rupture into masses of powdery, black spores.  This fungus tends to infect plants with a prior injury, perhaps from cultivation or insect feeding.  Smut usually affects a few plants in a field and is not considered an economically significant problem.  There is no effective fungicide for corn smut.

Smut on Corn

Smut on Corn, photo by David Handley

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
 % ECB
Damage
Recommendations / Comments
 Biddeford  36  11  0  2% 4-day spray interval for all silking corn
 Cape Elizabeth I  50  0  2  0% 4-day spray interval for all silking corn
 Cape Elizabeth II  20  1  2  0% 4-day spray interval for all silking corn
 Charleston  3  11  0  3% 6-day spray interval for all silking corn
 Dayton I  14  0  2  1% 4-day spray interval for all silking corn
 Dayton II  8  0  2  0% 4-day spray interval for all silking corn
 Dresden  9  0  0  2% 4-day spray interval for all silking corn
 East Corinth  0  6  0  0% One spray recommended for ECB on silking corn
 Farmington  1  1  0  2% No spray recommended
 Jefferson  7  1  0  4% 5-day spray interval for all silking corn
 Levant  11  13  0  10% 4-day spray interval for all silking corn
 Lewiston  4  0  0  0% 5-day spray interval for all silking corn
 Lewiston II  9  0  0  8% 4-day spray interval for all silking corn
 Livermore Falls  2  2  0  1% 6-day spray interval for all silking corn
 Monmouth  6  1  0  7% 5-day spray interval for all silking corn
 New Gloucester  26  0  0  1% 4-day spray interval for all silking corn
 Nobleboro  14  3  0  5% 4-day spray interval for all silking corn
 North Berwick  15  3  0  6% 4-day spray interval for all silking corn
 Oxford  10  0  0  4% 4-day spray interval for all silking corn
 Palmyra  4  5  0  6% 5-day spray interval for all silking corn
 Poland Spring  5  0  0  6% 5-day spray interval for all silking corn
 Sabattus  7  0  0  9% 5-day spray interval for all silking corn
 Wales  1  0  0  4% No spray recommended
 Warren  7  0  0  8% 5-day spray interval for all silking corn
 Wells I  40  0  1  7% 4-day spray interval for all silking corn
 Wells II  48  5  1  1% 4-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. 8 – August 1, 2012

Wednesday, August 1st, 2012

Sweet Corn

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

CORN EARWORM PRESSURE INCREASES IN SOUTHERN MAINE

European Corn Borer and Fall Armyworm Threat Remains Small

SITUATION
Harvest is still spotty as growers work through the erratic early corn and hope for better uniformity and quality with the main season crop.  Many fields received just enough rain to get a break from irrigation this week.  A little bit of weather coming up from the southeast coast appears to have bumped up local corn earworm populations, so silking corn is likely to need protection, especially in the southern and coastal areas of the state.

European corn borer:  Moth counts were higher in some northern locations this week, requiring protection of silking corn, but remained low in most southern fields.  Charleston, Levant, Palmyra and East Corinth were over the threshold of 5 moths in silking corn.  Feeding injury from larvae in whorl to tassel stage corn remained low in most locations this week, only exceeding the 15% feeding injury threshold in Cape Elizabeth and Poland Spring.

European Corn Borer Moth

European Corn Borer Moth, photo by David Handley

Corn earworm:  A significant increase in moth activity over the past two nights has increased the number of fields needing to protect any fresh silking corn.  A 4-day spray interval was recommended in one Cape Elizabeth location and North Berwick.  A 5-day spray interval was recommended for Biddeford, a second Cape Elizabeth location, Monmouth and New Gloucester.  A 6-day spray interval was recommended for fields in Lewiston,Warren and Wells.  Fields in Dayton, Jefferson, Palmyra, Poland Spring and Sabattus caught single moths, which does not warrant a spray.

Corn Earworm Moth

Corn Earworm Moth, photo by David Handley

Fall armyworm:  Two fall armyworm moths were caught in one Cape Elizabeth location this week.  This is below threshold for silking corn.  No feeding damage was found.

Spotted wing drosophila update:  The numbers and range of the “Suzuki Fruit Fly” continue to increase around the state.  We have found this small fruit fly in traps in Limington, Buxton, Sanford, New Gloucester, Mechanic Falls, Poland Spring, Wales, Litchfield, Fayette, Thorndike, Warren and Bucksport.  This week also saw the first capture of this fly in a wild blueberry field in Franklin.  Berry growers need to be on the alert for fruit flies and symptoms of premature fruit decay.  Have your pickers keep fields free of overripe fruit.  At this point, insecticide sprays every 5-7 days appears to provide adequate control.  More frequent sprays may become necessary as populations increase.  There is a good fact sheet about the management of spotted wing drosophila on the Penn State Extension website.

Male Spotted Wing Drosophila

Male and Female Spotted Wing Drosophila

Male and Female Spotted Wing Drosophila, image by Alan Kenage, Capital Press

Corn rust causes reddish-brown pustules to form on the leaves, stalks and husks, reducing the visual quality of the ears.  We see more of this problem in wet, humid seasons.  Some varieties are resistant.  Severe infections can reduce ear size, especially if they occur prior to tassel.  A fungicide spray for rust is only recommended if the infection occurs prior to tasseling.  Later infections are unlikely to cause enough damage to the crop to justify control measures.  Materials available to control corn rust include Bravo®, Quilt® and maneb/mancozeb.

Rust on Corn

Rust on Corn, photo by David Handley

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 % ECB Damage Recommendations / Comments
 Biddeford  7  3  0  4% 5-day spray interval for all silking corn
 Cape Elizabeth I  11  0  2  0% 4-day spray interval for all silking corn
 Cape Elizabeth II  6  0  0  21% 5-day spray interval for all silking corn
 Charleston  0  9  0  1% One spray recommended for ECB on silking corn
 Dayton I  1  1  0  3% No spray recommended
 Dayton II  1  0  0  1% No spray recommended
 Dresden  0  1  0  5% No spray recommended
 East Corinth  0  20  0  0% One spray recommended for ECB on silking corn
 Farmington  0  0  0  2% No spray recommended
 Jefferson  1  0  0  7% No spray recommended
 Levant  0  8  0  6% One spray recommended for ECB on silking corn
 Lewiston  2  1  0  0% 6-day spray interval for all silking corn
 Lewiston II  2  3  0  9% 6-day spray interval for all silking corn
 Monmouth  6  2  0  7% 5-day spray interval for all silking corn
 New Gloucester  5  0  0  2% 5-day spray interval for all silking corn
 North Berwick  8  0  0  1% 4-day spray interval for all silking corn
 Oxford  0  0  0  8% No spray recommended
 Palmyra  1  6  0  5% One spray recommended for ECB feeding
 Poland Spring  1  3  0  30% One spray recommended for ECB feeding
 Sabattus  1  1  0  8% No spray recommended
 Wales  0  0  0  13% No spray recommended
 Warren  3  0  0  7% 6-day spray interval for all silking corn
 Wells I  3  0  0  0% 6-day spray interval for all silking corn
 Wells II  3  0  0  1% 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.

Sweet Corn IPM Newsletter No. 7 – July 25, 2012

Wednesday, July 25th, 2012

Sweet Corn

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

CORN PEST ACTIVITY REMAINS LOW IN MOST LOCATIONS

Western Bean Cutworm Found in Maine Corn Fields

SITUATION
Early harvest is getting into full swing and corn quality is looking good, although ear size has been a bit small due to dry conditions in some areas.  Moth counts continue to be very low for this time of year, but nobody is complaining.

European corn borer:  Moth counts were very low in southern locations this week, but some northern sites continue to have enough moths flying to warrant protection of silking corn.  Three sites, Charleston, Levant and East Corinth were over the threshold of 5 moths in silking corn.  Feeding injury from larvae in whorl to tassel stage corn was also less prevalent this week, only exceeding the 15% feeding injury threshold in Biddeford, Jefferson, Poland Spring and Sabattus.

European Corn Borer in Tassel

European Corn Borer in Tassel, photo by David Handley

Corn earworm:  There was a slight increase in moth activity in a few locations this week.  A 6-day spray interval for fresh silking corn was recommended for fields in Nobleboro, North Berwick, Palmyra, and Poland Spring.  Three locations had only single moths, which don’t warrant a spray.  Most locations had no moths.

Corn Earworm Moth

Corn Earworm Moth, photo by David Handley

Fall armyworm:  No fall armyworm moths were caught this week and no feeding damage was found in the field.

Western bean cutworm:  A new corn pest for Maine?
We set out pheromone traps for western bean cutworm in cornfields this spring, based on reports that this insect is becoming a problem in corn in the upper Midwest and mid-Atlantic regions.  We have caught a few moths in Wells, Cape Elizabeth and New Gloucester over the past couple weeks, and we’re now evaluating what level of risk these present.  The larvae of western bean cutworm will feed on corn plants and move into the ears either through the silk channel or through the husks.  Unlike corn earworm, they are not cannibalistic; so many larvae may be found in a single ear, feeding on the kernels.  The threshold for feeding injury on plants is 8%.  There isn’t an established threshold for moths laying eggs in silking corn yet, but plants that are already on a spray program for corn earworm should also be protected from western bean cutworm.

Spotted wing drosophila update:  We have found this “new” fruit fly in more locations and in higher numbers this week, threatening raspberries, blueberries and any other soft fruit that is available.   We have now caught this fly in traps in Limington, Sanford, New Gloucester, Mechanic Falls, Wales, Litchfield, Fayette, Thorndike, and Warren.  Growers should be on the alert and look for fruit flies on their fruit and symptoms of premature fruit decay.  At this point, keeping fields free of overripe fruit and weekly insecticide sprays appear to be keeping this pest in check.  However more frequent sprays may become necessary as pest populations increase.  There is a good fact sheet on management of spotted wing drosophila on the Penn State Extension website.

Male and Female Spotted Wing Drosophila Flies

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

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

Highmoor Farm                      PestManagement 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
%ECB
Damage
Recommendations / Comments
 Biddeford  0  0  0  30% One spray recommended for ECB feeding
 Cape Elizabeth I  0  0  0  6% No spray recommended
 Cape Elizabeth II  0  0  0  10% No spray recommended
 Charleston  0  5  0  1% One spray recommended for ECB on silking corn
 Dayton I  0  0  0  0% No spray recommended
 Dayton II  1  0  0  0% No spray recommended
 Dresden  0  0  0  9% No spray recommended
 East Corinth  0  6  0  0% One spray recommended for ECB on silking corn
 Farmington  0  1  0  3% No spray recommended
 Jefferson  0  0  0  19% One spray recommended for ECB feeding
 Levant  0  5  0  5% One spray recommended for ECB on silking corn
 Lewiston  0  0  3% No spray recommended
 Lewiston II  0  0  0  13% No spray recommended
 Livermore Falls  1  0  0  1% No spray recommended
 Monmouth  0  1  0  0% No spray recommended
 New Gloucester  0  0  0  2% No spray recommended
 Nobleboro  2  0  0  0% 6-day spray interval for all silking corn
 North Berwick  2  0  0  0% 6-day spray interval for all silking corn
 Oxford  0  1  0  5% No spray recommended
 Palmyra  2  3  0  3% 6-day spray interval for all silking corn
 Poland Spring  2  0  0  21% 6-day spray interval for all silking corn
 Sabattus  0  0  0  23% One spray recommended for ECB feeding
 Wales  0  0  0  0% No spray recommended
 Warren  0  0  0  0% No spray recommended
 Wells I  1  0  0  0% No spray recommended
 Wells II  0  1  0  6% 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 – July 19, 2012

Thursday, July 19th, 2012

Sweet Corn

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

WARM NIGHTS LEAD TO CORN GROWTH, PEST ACTIVITY STILL LOW

Spotted Wing Drosophila Alert

SITUATION
Despite the warmer night temperatures over the weekend, moth counts remain low.  In many places, the warm nights helped the corn grow rapidly, while in other places corn is exhibiting symptoms of dehydration because of the lack of rain.

European corn borer:  Moth counts continue to be very low this week.  Two sites, Levant and East Corinth were over the threshold of 5 moths in silking corn.  Feeding injury from larvae in whorl to tassel stage corn exceeded the 15% feeding injury threshold in Biddeford, one Cape Elizabeth location, Jefferson, one Lewiston location, Oxford, Poland Spring, Sabattus and one Wells location this week.

 

European Corn Borer on Ear

European Corn Borer on Ear, photo by David Handley

Corn earworm:  No sprays were recommended for corn earworm this week.  Most locations had no moths, and the locations where corn earworm was present only saw a single moth, which doesn’t warrant a spray.

Fall armyworm:  Though we were expecting moth counts to increase after the warmer nights over the weekend, no fall armyworm moths were caught this week and we have not yet seen any sign of larvae feeding.

Spotted Wing Drosophila (SWD) Alert:  This is a new pest which is a concern for raspberries, blueberries, and day-neutral strawberries, as well as many other soft fruits.  This insect is a small fruit fly, similar to the type that fly around the over-ripe bananas in your kitchen.  However, this species will lay its eggs in fruit before it ripens, resulting in fruit that is contaminated with small white maggots just as it is ready to pick.  As a result, the fruit quickly rots and has no shelf life.  This insect recently came into the U.S. from northern Asia, and caused problems with many berry crops up the east coast last year.  It can complete a generation in under two weeks, with each adult female laying hundreds of eggs.  Therefore, millions of flies can be present soon after the introduction of  just a few into 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 in a field.  Now that spotted wing drosophila has been confirmed in Limington, Mechanic Falls, Springvale, Thorndike, and Warren, growers should be on the alert and look for fruit flies on their fruit and symptoms of premature fruit decay.  Products that provide good control of drosophila on berries include Delegate®, Brigade®, Danitol®, and malathion.  Please check product labels for rates, post-harvest intervals and safety precautions. Keeping the fields clean of over-ripe and rotten fruit can also help reduce the incidence of this insect. For information on identifying spotted wing drosophila and making your own monitoring traps, visit the Michigan State University’s Spotted Wing Drosophila.  There is also a good fact sheet on management of spotted wing drosophila on the Penn State Extension website.

Male and Female Spotted Wing Drosophila Flies

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
%ECB Damage Recommendations / Comments
 Biddeford  1  0  0  24% One spray recommended for ECB feeding
 Cape Elizabeth I  0  1  0  1% No spray recommended
 Cape Elizabeth II  0  0  0  29% One spray recommended for ECB feeding
 Charleston  0  1  0  0% No spray recommended
 Dayton I  1  0  0  0% No spray recommended
 Dayton II  1  1  0  0% No spray recommended
 Dresden  0  0  0  3% No spray recommended
 East Corinth  0  6  0  2% One spray recommended for ECB on silking corn
 Farmington  1  0  0  6% No spray recommended
 Jefferson  1  1  0  25% One spray recommended for ECB feeding
 Levant  0  5  0  5% One spray recommended for ECB on silking corn
 Lewiston  1  1  0  2% No spray recommended
 Lewiston II  0  2  0  13% No spray recommended
 Livermore Falls  0  0  0  2% No spray recommended
 Monmouth  0  0  0  0% No spray recommended
 New Gloucester  0  0  0  1% No spray recommended
 Nobleboro  0  4  0  4% No spray recommended
 North Berwick  0  0  0  4% No spray recommended
 Oxford  0  0  0  27% One spray recommended for ECB feeding
 Palmyra  0  3  0  1% No spray recommended
 Poland Spring  1  0  0  41% One spray recommended for ECB feeding
 Sabattus  0  0  0  19% One spray recommended for ECB feeding
 Wales  0  0  0  0% No spray recommended
 Warren  0  0  0  7% No spray recommended
 Wells I  1  1  0  18% One spray recommended for ECB feeding
 Wells II  0  0  0  2% 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.