Posts Tagged ‘sweet corn’

Sweet Corn IPM Newsletter No. 3 – July 7, 2017

Friday, July 7th, 2017

Sweet CornSweet Corn IPM Newsletter No. 3 – July 7, 2017
Click on photos to enlarge.

Highmoor Farm Field Day
Wednesday, July 26, 2017
Save the date!

CORN EARWORM ACTIVE IN SILKING CORN FIELDS

European Corn Borer Feeding Increasing in Pre-Tassel Fields

SITUATION
Early corn, planted under plastic mulch or row covers is coming into silk this week, while early corn planted without plastic is now in pre-tassel. Warmer growing conditions have kept corn growth at a brisk pace, but has allowed increased insect activity in some fields. Sprays have been recommended for both European corn borer and corn earworm this week.

European Corn Borer Damage on Pre-tassel Stage corn

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

European corn borer:  Moth captures were lower in most locations this week, but larval feeding activity was found in nearly all the fields we scouted. Most fields were still under the recommended spray thresholds of 30% of whorl-stage plants showing feeding injury or 15% of pre-tassel plants. Fields in Bowdoinham, Cape Elizabeth and Wells were over threshold for either whorl or pre-tassel corn, so sprays were recommended. In silking corn, the sprays may be based on the number of corn borer moths caught in pheromone traps to prevent moths from laying eggs on the flag leaves of the ears, which could lead to larvae infesting the ears. One early silking field in Cape Elizabeth was over the 5-moth threshold, but the field was also on a spray interval for corn earworm, so no additional sprays should be needed.

Corn earworm:  We continue to catch moths at some, but not all locations, and in relatively low numbers. The weather has been conducive to more moths flying northward, and egg laying at night, so growers with early corn should be on the alert to protect any silking fields if moths are found in the area. A 6-day spray interval for corn earworm was recommended for early silking fields in Wells and Dayton this week. A 5-day spray interval was recommended for silking fields in Cape Elizabeth and Lewiston. When no silking corn is available, corn earworm larvae may chew large, ragged holes in the leaves, similar to fall armyworm. This should be counted in field scouting for European corn borer and fall armyworm.

drosophila trap

Drosophila Trap, photo by David Handley

Fall armyworm:  No moths have been captured in our pheromone traps this week, and no feeding damage has been reported. We do expect that moths will be arriving soon, as they typically follow corn earworm into Maine by a few days to a few weeks.

Spotted wing drosophila: Flies have been caught in other New England states this week, and Dr. Frank Drummond, University of Maine Entomologist, reports flies found in Stockton Springs. We have found one female SWD from a trap in Buxton. Growers with ripening blueberries or raspberries should be on the alert for flies or larvae in the fruit.

Squash vine borer moths were caught in pheromone traps in Wells, Biddeford, Oxford and New Gloucester this week. Only the Wells site was above the 5 moths per week spray threshold, and a spray was recommended, but the captures in other locations indicate that this pest is now threatening summer squash, winter squash and pumpkins in Maine fields. Growers with squash in southern Maine should be on the lookout for vine borer symptoms and protect squash plants if moths or damage are seen. See the 2016-2017 New England Vegetable Management Guide for control options.

Two Squash Vine Borer Moths

Two Squash Vine Borer Moths, photo by Jeffrey Hahn, Univ. of Minnesota Extension

Squash Vine Borer Larva

Squash Vine Borer Larva, photo by Jeffrey Hahn, Univ. of Minnesota Extension

Sincerely,

David T. Handley
Vegetable and 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
Biddeford 1 0 0 20% No spray recommended (corn not yet pre-tassel)
Bowdoinham 0 1 0 22% One spray recommended for ECB
Cape Elizabeth I 0 0 0 1% No spray recommended
Cape Elizabeth II 5 6 0 20% 5-day spray interval recommended on all silking corn
Dayton I 1 0 0 2% No spray recommended
Dayton II 3 0 0 9% 6-day spray interval recommended on all silking corn
Farmington 0 0 0 7% No spray recommended
Lewiston 4 0 0 2% 5-day spray interval recommended on all silking corn
Nobleboro 1 0 0 7% No spray recommended
Oxford 0 1 0 1%
Poland Spring 0 0 0 21% No spray recommended (corn not yet pre-tassel)
Sabattus 0 0 0 26% One spray recommended for ECB
Wayne 0 0 0 19% One spray recommended for ECB on pre-tassel corn
Wells I 0 0 0 19% One spray recommended for ECB on pre-tassel corn
Wells II 3 0 0 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:
UMaine Cooperative Extension IPM
Penn State Sweet Corn IPM
UMass Extension IPM Programs

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.

The University of Maine is an equal opportunity/affirmative action institution.

 

Sweet Corn IPM Newsletter No. 2 – June 30, 2017

Friday, June 30th, 2017

Sweet CornSweet Corn IPM Newsletter No. 2 – June 30, 2017
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Highmoor Farm Field Day
Wednesday, July 26, 2017
Save the date!

CORN EARWORM THREATENS EARLY SILKING CORN

European Corn Borer Feeding in Pre-Tassel Fields

SITUATION
Cool, wet growing conditions this spring delayed planting in many fields, and those that were planted early have been slow to get established. Early fields in southern Maine are coming into pre-tassel and a few fields that were transplanted or started under plastic or row covers are just starting to silk. Both corn earworm and European corn borer are already active in much of the state, and pose a threat to these early silking fields.

European Corn Borer Larva

European Corn Borer Larva, photo by David Handley

European corn borer:  Moths were caught in pheromone traps all around the state this week, and larval feeding damage is showing up on early corn. In whorl stage corn the control threshold is 30% of plants showing feeding injury. Once the plants reach the pre-tassel stage the threshold is lowered to 15%, because larvae at this stage are more likely to damage the ears. Early fields in North Berwick, Poland Spring and Sabattus were over threshold for either whorl or pre-tassel corn, so sprays were recommended. Once corn reaches the silk stage, sprays may be based on the number of corn borer moths caught in pheromone traps rather than feeding injury. If more than 5 moths are caught in pheromone traps in a week near silking corn, a spray is recommended to prevent moths from laying eggs on the flag leaves of the ears, which could lead to larvae infesting the ears while leaving no visible signs of feeding on the leaves. One early silking field in Dayton was over the 5-moth threshold this week.

Corn earworm:  Moths were caught in pheromone traps around much of the state this week. This is a fairly early arrival; but not too surprising, because much of our weather in the past few weeks has been moving up from the south, carrying moths with it. However, there is very little silking corn available for the moths to lay eggs on at this time, so the threat is very low for most fields. When more than one corn earworm moth is found at a site, all silking corn in the fields should be protected with a spray. Additional sprays are based on the average number of moths caught per week or per night (see table below). A 5-day spray interval for corn earworm was recommended for one early silking field in New Gloucester. When no silking corn is available, corn earworm moths may lay eggs on corn leaves, and the larvae will chew large, ragged holes in the leaves, similar to fall armyworm.

Fall armyworm:  No moths have been captured in our pheromone traps this week, and no feeding damage has been reported. Although this is usually the last major corn pest to arrive in Maine from southern overwintering sites, it often follows corn earworm closely, and was the most significant pest problem in most corn fields last season.

Two Squash Vine Borer Moths

Two Squash Vine Borer Moths, photo by Jeffrey Hahn, Univ. of Minnesota Extension

Squash vine borer moths were caught in pheromone traps in Wells and Oxford this week. Counts were below the 5 moths per week spray threshold, but the captures suggest this pest will be a threat to summer squash, winter squash and pumpkins this season. Squash vine borer moths are black and orange and resemble wasps. They lay their eggs at the base of squash plants. The larvae bore into the base of the plants, causing vines to wilt and eventually collapse. Growers with squash in southern Maine should be on the lookout for vine borer symptoms and protect squash plants if moths or damage are seen. See the 2016-2017 New England Vegetable Management Guide for control options.

Sincerely,

David T. Handley
Vegetable and 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
Biddeford 0 2 0 11% No spray recommended
Bowdoinham 0 0 0 14% No spray recommended
Cape Elizabeth I 1 0 0 0% No spray recommended (corn not yet silking)
Cape Elizabeth II 4 8 0 24% No spray recommended (corn not yet pre-tassel)
Dayton I 1 5 0 0% One spray for ECB on silking corn
Dayton II 1 0 0 0% No spray recommended (corn not yet silking)
Farmington 0 2 0 4% No spray recommended
Lewiston I 4 0 0 1% No spray recommended (corn not yet silking)
Lewiston II 3 0 0 4% No spray recommended (corn not yet silking)
New Gloucester 4 0 0 5-day spray interval recommended on all silking corn
Nobleboro 4 1 0 17% No spray recommended (corn not yet pre-tassel)
No. Berwick 2 7 0 40% One spray for ECB on pre-tassel corn (not yet silking)
Oxford 1 1 0 2% No spray recommended (corn not yet silking)
Poland Spring 1 3 0 63% One spray for ECB on whorl-stage corn (not yet silking)
Sabattus 0 2 0 16% One spray recommended for ECB
Wales 4% No spray recommended
Wayne 0 0 0 10% No spray recommended
Wells I 3 3 0 0% No spray recommended (corn not yet silking)
Wells II 2 3 0 0% No spray recommended (corn not yet silking)

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:
UMaine Cooperative Extension IPM
Penn State Sweet Corn IPM
UMass Extension IPM Programs

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.

The University of Maine is an equal opportunity/affirmative action institution.

 

Sweet Corn IPM Newsletter No. 1 – June 23, 2017

Friday, June 23rd, 2017

Sweet CornSweet Corn IPM Newsletter No. 1 – June 23, 2017
Click on photos to enlarge.

2017 SWEET CORN PEST SEASON BEGINS!

European Corn Borer Active in Early Fields

The 2017 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. We have set up pheromone traps at these locations to monitor the adult (moth) stages of European corn borer, corn earworm and fall armyworm, and we are scouting the fields for feeding injury by insect larvae. We will share the information we collect along with management recommendations through this newsletter 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.

SITUATION
A cool, wet start to the season has delayed both the planting and emergence of sweet corn. Early plantings in southern Maine and plots started under plastic or row covers are mostly at late whorl or pre-tassel. Late fields are just starting to emerge. Early scouting has not shown any significant insect problems at this time, although we expect European corn borer to become active soon.

European corn borer:  Pheromone traps for moths are set up in the grassy borders around cornfields. We have begun scouting late whorl and pre-tassel fields in southern Maine, but have not yet found any larvae feeding on the leaves or emerging tassels. In the early stages, European corn borer larvae are very small and translucent with shiny black heads. They emerge from small egg masses that look like a tiny clump of overlapping fish scales on the undersides of corn leaves. European corn borer overwinters in Maine, and 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 provides a good estimate of the total amount of injury in a field.

European Corn Borer Moth

European Corn Borer Moth, photo by David Handley

European Corn Borer Damage

European Corn Borer Damage, photo by David Handley

In the early stages, European corn borer feeding damage looks like small “pinholes” in the leaves. Whorl stage corn 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% because larvae feeding on the later stages are more likely to move into the ears. On the tassels, feeding damage first appears as chewing and brown waste found in the small florets. After the tassel has emerged from the whorl, 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, target the larvae before can they move into the protection of the stalks and ears. 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®.

Growers should start scouting whorl stage corn for feeding injury now. Once 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. If more than five moths are caught during a week in a field with silking corn, a spray is 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.

Corn Earworm Moth

Corn Earworm Moth, photo by David Handley

Corn earworm:  We have set up pheromone traps around the state for corn earworm moths. 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 are 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 or tassels 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.

 

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. Last year, fall armyworm moths arrived in Maine relatively early in the season, and were often more of a threat than corn earworm. This was an unusual situation for Maine and we will be watching fall armyworm closely this year to see if this is a new, unfortunate trend.

Common armyworm:  There have been reports of serious infestations of common armyworm in silage corn, alfalfa and hayfields this spring. Common armyworm can become active as early as April in Maine and can become a problem in early planted sweet corn. However, if the corn is established, it will outgrow the injury, as the caterpillars usually pupate before the ears develop. However, when heavy infestations occur, control may be required.  Common armyworm larvae are brown with yellow and black stripes running along the body. They chew large, ragged holes in the leaves, similar to fall armyworm.

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).

European Corn Borer Trap

European Corn Borer Trap, photo by David Handley

Harstack Trap

Harstack Trap, photo by David Handley

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 our website at http://umaine.edu/ipm/ipddl/publications/5101e/ or call the Pest Management Office at 1.800.287.0279.

Sincerely,

David T. Handley
Vegetable and 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

IPM Web Pages:
UMaine Cooperative Extension IPM
Penn State Sweet Corn IPM
UMass Extension IPM Programs

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

The University of Maine is an equal opportunity/affirmative action institution.

 

Sweet Corn IPM Newsletter No. 12 – September 9, 2016

Friday, September 9th, 2016

Sweet CornSweet Corn IPM Newsletter No. 12 – September 9, 2016
Click on photos to enlarge.

Last Issue for 2016!

FALL ARMYWORM STILL A THREAT TO LATE CORN

Corn Earworm Numbers Very Low for Late Season

This will be the final issue of the Sweet Corn IPM Newsletter for the 2016 season. I would like to thank all of the growers who participated in the program this year, and our team of IPM scouts, including Shannon Buzzell, Hannah Kerrigan, Lindsey Ridlon and Sean McAuley. Have questions, comments or suggestions about the program? Please call or e-mail us.

SITUATION
The tropical storm front that passed by us does not appear to have come close enough to bring in a new wave of corn earworm, as populations were quite low this week. Despite the absence of corn earworm, continued hot weather, combined with the difficulty of keeping fall armyworm in check, suggests that growers with silking corn remaining should maintain a regular spray schedule to keep larvae from infesting late ripening ears.

European corn borer:  Moths were essentially a “no show” this week as we only caught single moths at two sites over the entire region. As a result, no sprays for corn borer were recommended. Remember to chop up stalks and stubble after harvest to reduce potential overwintering sites for corn borer larvae.

Corn earworm:  Moth counts were very low around the state this week, with the exception of a few coastal sites. Only three sites had spray recommendations as a result. A 6-day spray interval for silking corn was recommended at one Cape Elizabeth site. A 4-day spray interval was recommended at one Cape Elizabeth site and Nobleboro.

Corn Earworm Feeding on Corn

Corn Earworm Feeding on Corn, photo by David Handley

Fall Armyworm on Corn Leaf

Fall Armyworm on Corn Leaf, photo by David Handley

Fall armyworm:  Moth counts were somewhat lower at most sites this week, but continued to be over the spray threshold for silking corn in many locations. Moth catches were over the 3-moth spray threshold in Biddeford, Cape Elizabeth, Dayton, Hollis, Durham, Levant, Monmouth, New Gloucester, Nobleboro, North Berwick, Oxford, Poland Spring, Wales, Warren, Wayne and Wells. As mentioned last week, fall armyworm has been the most persistent pest problem in corn this season. Some crops have seen relatively high infestation rates, despite regular sprays. This insect has often been difficult to control, especially when we have high numbers during silking. It is also important to note that insecticide products may break down more rapidly in very hot weather, especially synthetic pyrethroids (Group 3A), so shortening times between sprays may help improve control.

Hops Twilight Meeting:  Join us at the Hop Yard in Gorham, Maine on Wednesday, September 14 from 5:00 p.m. to 7:30 p.m. for a tour of a commercial hops planting, and discussion about the potential for this crop in Maine. For details please visit our web blog.

Highmoor FarmHighmoor Farm Twilight Meeting:  Come join us at the Maine Agricultural and Forest Experiment Station in Monmouth, Maine on Wednesday, September 21 from 5:00 p.m. to 7:30 p.m. for a tour of pumpkin, pepper, high tunnel tomato, and other vegetable trials. Dr. Mark Hutton, Extension Vegetable Specialist, will be on hand to talk about crop performance this year. More details will be coming soon on our Highmoor Farm website.

Sincerely,

David T. Handley
Vegetable and 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
Biddeford 1 0 10 One spray for FAW on silking corn
Bowdoinham 0 0 0 No spray recommended
Cape Elizabeth I 3 0 39 6-day spray interval on silking corn for CEW
Cape Elizabeth II 14 0 24 4-day spray interval on silking corn for CEW
Corinth 0 1 1 No spray recommended
Dayton 0 0 6 One spray for FAW on silking corn
Hollis 2 0 24 6-day spray interval on silking corn for CEW
Durham 1 0 13 One spray for FAW on silking corn
Levant 2 0 3 6-day spray interval on silking corn for CEW
Lewiston 0 0 0 No spray recommended
Monmouth 0 0 11 One spray for FAW on silking corn
New Gloucester 1 0 61 One spray for FAW on silking corn
Nobleboro 13 0 42 4-day spray interval on silking corn for CEW
No. Berwick 0 0 16 One spray for FAW on silking corn
Oxford 0 0 21 One spray for FAW on silking corn
Palmyra 0 0 1 No spray recommended
Poland Spring 0 1 3 One spray for FAW on silking corn
Sabattus 0 0 2 No spray recommended
Wales 0 0 4 One spray for FAW on silking corn
Warren 1 0 24 One spray for FAW on silking corn
Wayne 0 0 11 One spray for FAW on silking corn
Wells I 0 0 5 One spray for FAW on silking corn
Wells II 0 0 41 One spray for FAW on 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:
UMaine Cooperative Extension IPM
Penn State Sweet Corn IPM
UMass Extension IPM Programs

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.

The University of Maine is an equal opportunity/affirmative action institution.

Sweet Corn IPM Newsletter No. 11 – September 2, 2016

Friday, September 2nd, 2016

Sweet CornSweet Corn IPM Newsletter No. 11 – September 2, 2016
Click on photos to enlarge.

CORN PEST NUMBERS MOSTLY LOWER THIS WEEK

Impending Tropical Storm May Bring More Corn Pests with It

SITUATION
No relief from the drought this week, and some late maturing fields are showing signs of drought stress, as farmers struggle to keep up with irrigation demands. Supply and quality continue to be good, however, despite the very dry conditions. The weather seems to have held off any increases in pest populations as well. Most fields saw lower pest pressure this week; although some farmers have noted difficulty in keeping armyworm under control, even with repeated sprays. Next week’s issue of the Sweet Corn IPM Newsletter is the last planned for the 2016 season.

European corn borer: Moth counts were very low this week, indicating that any second generation that may have been starting has petered out. No sites were over the threshold of moths for silking corn. European corn borer overwinters as larvae in corn stalks and stubble left in the field. Plowing down cornfields after harvest will greatly reduce overwintering sites and prevent early infestations next year. Plant a cover crop, such as oats or winter rye, following plow down to reduce erosion during the winter and to preserve organic matter and soil nutrients.

Corn earworm: Moth counts are lower this week at nearly all locations, with the exceptions of our most northern sites. No sprays for corn earworm were recommended in Biddeford, Bowdoinham, Durham, Monmouth, Oxford, Palmyra, Poland Spring, Sabattus, Wales, Wayne, and one Wells site. A 6-day spray interval for silking corn was recommended in Charleston, Corinth, Dayton, Hollis, Levant and Warren. A five-day spray interval was recommended at one Cape Elizabeth site, Lewiston, North Berwick, and one Wells site. A 4-day spray interval was recommended at one Cape Elizabeth site, New Gloucester, and Nobleboro. The approach of a tropical storm early next week could change corn earworm populations quickly, as these storms often drag up moths from more southern locations.

Adult Fall Armyworm

Adult Fall Armyworm, photo by David Handley

Fall armyworm: Moth counts were generally lower this week, but continue to be over the spray threshold for silking corn in most locations. Moth catches were over the 3-moth spray threshold in Biddeford, Cape Elizabeth, Charleston, Hollis, Durham, Lewiston, Monmouth, New Gloucester, Nobleboro, North Berwick, Oxford, Palmyra, Poland Spring, Sabattus, Warren, Wayne and one Wells site.

Fall armyworm larvae have been difficult to control in some fields, despite regular sprays. Sprays for armyworm are most effective when targeted for the late pre-tassel to tassel stage because the larvae are most exposed at this stage and less protected by leaves or husks. The larvae also tend to be more exposed at night, making evening sprays more effective. The addition of a spreader-sticker with the insecticide can also help to get the best coverage possible and extend the effective time of the application.

Hops Plant

Hops Plant, photo by David Handley

Hops Twilight Meeting: Come join us at the Hop Yard in Gorham, Maine on Wednesday, September 14 from 5 p.m. to 7:30 p.m. for a tour of a commercial hops planting, and discussion about the potential for this crop in Maine. For details please visit our web blog.

Sincerely,

David T. Handley
Vegetable and 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
Biddeford 1 0 48 One spray for FAW on silking corn
Bowdoinham 0 0 0 No spray recommended
Cape Elizabeth I 6 0 46 5-day spray interval on silking corn for CEW
Cape Elizabeth II 16 0 36 4-day spray interval on silking corn for CEW
Charleston 2 0 14 6-day spray interval on silking corn for CEW
Corinth 2 1 1 6-day spray interval on silking corn for CEW
Dayton 2 0 0 6-day spray interval on silking corn for CEW
Hollis 3 1 18 6-day spray interval on silking corn for CEW
Durham 0 0 21 One spray for FAW on silking corn
Levant 2 0 2 6-day spray interval on silking corn for CEW
Lewiston 5 1 6 5-day spray interval on silking corn for CEW
Monmouth 1 0 12 One spray for FAW on silking corn
New Gloucester 8 3 96 4-day spray interval on silking corn for CEW
Nobleboro 12 2 42 4-day spray interval on silking corn for CEW
No. Berwick 5 1 22 5-day spray interval on silking corn for CEW
Oxford 1 2 38 One spray for FAW on silking corn
Palmyra 0 0 12 One spray for FAW on silking corn
Poland Spring 1 2 6 One spray for FAW on silking corn
Sabattus 0 3 8 One spray for FAW on silking corn
Wales 0 1 1* No spray recommended (*FAW trap down)
Warren 2 3 22 6-day spray interval on silking corn for CEW
Wayne 0 1 7 One spray for FAW on silking corn
Wells I 0 0 1 No spray recommended
Wells II 6 0 43 5-day spray interval on silking corn for CEW

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:
UMaine Cooperative Extension IPM
Penn State Sweet Corn IPM
UMass Extension IPM Programs

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.

The University of Maine is an equal opportunity/affirmative action institution.

Sweet Corn IPM Newsletter No. 10 – August 26, 2017

Friday, August 26th, 2016

Sweet CornSweet Corn IPM Newsletter No. 10 – August 26, 2016
Click on photos to enlarge.

CORN EARWORM THREATENS LATE SILKING CORN

Fall Armyworm also Attacking Late Corn

SITUATION
A little bit of much-needed rain last weekend offered some relief to the dry conditions, but also brought an increase in corn earworm activity in most fields. Fall armyworm counts continue to be high at most sites, and birds and mammals have been causing lots of damage to ripening fields. Growers are still spending much of their time managing irrigation, and as a result the supply and quality of corn has been very good.

European corn borer: Moth counts have been rising in some locations this week, suggesting a second generation of European corn borer may be getting underway. However, in most cases fields are now under a spray schedule for corn earworm, and therefore no additional sprays should be required. Fields in Poland Spring, Sabattus, Wales, Warren and one Wells site exceeded the 5-moth control threshold for silking corn. Only the field in Sabattus was not already under a spray interval for corn earworm, so a spray for silking corn was recommended.

Corn earworm: Moth counts are generally higher around the state this week. Most farms are now on a spray schedule for corn earworm on all silking corn. A 6-day spray interval for all silking corn was recommended in Bowdoinham, one Cape Elizabeth site, Dayton, Levant, North Berwick, Oxford, and Wales. A five-day spray interval was recommended in Biddeford, Monmouth, Poland Spring, Wayne, and one Wells site. A 4-day spray interval was recommended at one Cape Elizabeth site, Hollis, Lewiston New Gloucester, Nobleboro, Warren, and one Wells site.

Fall armyworm: Moth counts continue to be over the spray threshold for silking corn in most locations, but most of these fields are now under a regular spray schedule for corn earworm, so no additional sprays should be needed for fall armyworm. Moth catches were over the 3-moth spray threshold in Biddeford, Bowdoinham, Cape Elizabeth, Dayton, Hollis, Durham, Levant, Lewiston, Monmouth, New Gloucester, Nobleboro, North Berwick, Oxford, Poland Spring, Sabattus, Wales, Warren, Wayne and one Wells site. Most of the remaining corn is in silk, so spray recommendations are being based on trap catches rather than field scouting for plant damage. Fall armyworm pressure will likely remain high for the rest of the season.

Fall Armyworm on Corn Silk

Fall Armyworm on Corn Silk, photo by David Handley

SWD Maggot in Raspberry

SWD Maggot in Raspberry, photo by David Handley

Spotted wing drosophila: Fly numbers continue to rise, but have only increased dramatically in plantings that have not been sprayed, indicating that sprays have been effective at keeping infestations at manageable levels in most fields. Berry growers should continue spraying ripening fruit regularly to prevent infestations. A 7-day spray schedule appears to be providing adequate protection at this time. For more information visit our Spotted Wing Drosophila blog.

Hops Plant

Hops Plant, photo by David Handley

Hops Twilight Meeting: Are you interested in growing hops? There has been lots of talk about the potential for this crop in Maine. Come join us at the Hop Yard, 26 Hamblen Drive, Gorham, Maine on Wednesday, September 14 from 5:00 p.m. to 7:30 p.m. Grower Ryan Houghton will tour us through the planting and discuss his experience in starting a commercial hops planting. David Handley and Jim Dill from the University of Maine Cooperative Extension will also be on hand to discuss growing practices and pest problems. Hold the date! More details are coming soon.

Sincerely,

David T. Handley
Vegetable and 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
Biddeford 4 0 42 5-day spray interval on silking corn for CEW
Bowdoinham 2 0 15 6-day spray interval on silking corn for CEW
Cape Elizabeth I 12 0 50 4-day spray interval on silking corn for CEW
Cape Elizabeth II 3 2 65 6-day spray interval on silking corn for CEW
Charleston 0 0 0 No spray recommended
Corinth 0 1 0 No spray recommended
Dayton 3 0 3 6-day spray interval on silking corn for CEW
Hollis 13 1 35 4-day spray interval on silking corn for CEW
Durham 0* 0 4 One spray for FAW on silking corn (*CEW trap down)
Levant 2 0 7 6-day spray interval on silking corn for CEW
Lewiston 13 2 33 4-day spray interval on silking corn for CEW
Monmouth 6 1 35 5-day spray interval on silking corn for CEW
New Gloucester 9 2 100 4-day spray interval on silking corn for CEW
Nobleboro 12 2 24 4-day spray interval on silking corn for CEW
No. Berwick 3 2 32 6-day spray interval on silking corn for CEW
Oxford 3 2 59 6-day spray interval on silking corn for CEW
Palmyra 0 1 0 No spray recommended
Poland Spring 5 12 9 5-day spray interval on silking corn for CEW
Sabattus 0 19 3 One spray for ECB on silking corn
Wales 2 6 3 6-day spray interval on silking corn for CEW
Warren 12 23 51 4-day spray interval on silking corn for CEW
Wayne 7 1 30 5-day spray interval on silking corn for CEW
Wells I 6 2 2 5-day spray interval on silking corn for CEW
Wells II 11 5 156 4-day spray interval on silking corn for CEW

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:
UMaine Cooperative Extension IPM
Penn State Sweet Corn IPM
UMass Extension IPM Programs

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.

The University of Maine is an equal opportunity/affirmative action institution.

Sweet Corn IPM Newsletter No. 9 – August 19, 2016

Friday, August 19th, 2016

Sweet CornSweet Corn IPM Newsletter No. 9 – August 19, 2016
Click on photos to enlarge.

CORN EARWORM NUMBERS INCREASING

Fall Armyworm Damaging Pre-Tassel Corn

SITUATION
While dry conditions continue to dominate grower concerns, harvested cornfields are now being plowed down to make ready for cover crops. Mid and late season corn harvest is underway. The high temperatures have hastened ripening of many fields, condensing the harvest window and making the supply less consistent than usual. Insect pressure is higher in some, but not all, locations this week. Fall armyworm feeding in younger corn is still a concern in late maturing fields.

European corn borer: We are still finding low numbers of moths in most locations, but some sites have seen an increase in trap catches this week. Fields in Levant, North Berwick, Palmyra, Sabattus, Warren and one Wells site exceeded the 5-moth control threshold for silking corn. The fields in North Berwick, Palmyra and Sabattus were not already under a spray interval for corn earworm, so a spray was recommended. Larval feeding damage was very light, with no fields exceeding the 15% pre-tassel threshold.

Corn earworm: Moth counts were inconsistent around the state, with some fields showing a significant increase in numbers from last week, and many fields still catching very few or no moths. A 6-day spray interval for all silking corn was recommended in Bowdoinham, Levant, Livermore Falls, New Gloucester, Nobleboro and Oxford. A five-day spray interval was recommended in Biddeford, one Cape Elizabeth site and one Wells site. A 4-day spray interval was recommended at one Lewiston site, and Warren.

Corn Earworm Moth

Corn Earworm Moth, photo by David Handley

Fall Armyworm on Corn Silk

Fall Armyworm on Corn Silk, photo by David Handley

Fall armyworm: Moth counts were high in more locations this week, although a few sites still have not exceeded the threshold for silking corn. Moth counts did exceed the 3-moth spray threshold in Biddeford, Cape Elizabeth, Farmington, Levant, Lewiston, Monmouth, New Gloucester, Nobleboro, Oxford, Wales, Warren and one Wells site. Larval feeding damage exceeded the 15% feeding injury threshold on pre-tassel corn in Cape Elizabeth, Hollis, one Lewiston site, Livermore Falls, New Gloucester, Oxford and one Wells site. Some locations now have all of their remaining corn in silk, so sprays are based primarily on trap catches rather than field scouting for plant damage. High moth catches suggest armyworm pressure will remain high in the coming weeks.

Spotted wing drosophila: Fly numbers are climbing around the state, but haven’t yet exploded. However, nearly all of our trapping sites are now over the recommended threshold for protecting ripening fruit. Berry growers should be spraying ripening fruit regularly to prevent infestations. At this point, a 7-day spray schedule should provide adequate protection. For more information visit our Spotted Wing Drosophila blog.

Spotted Wing Drosophila Larvae in Raspberry

Spotted Wing Drosophila Larvae in Raspberry, photo by David Handley

Bird Damage on Corn

Bird Damage on Corn, photo by David Handley

Birds, etc.: Flocking species of blackbirds have been damaging cornfields around the state. Birds tend to be more of a problem in dry years, when food and water is more difficult to find. They are especially attracted to fields where corn has been allowed to get over-mature. Deer and raccoons have also been very troublesome this year. For information on wildlife problems and management options, you may call the Animal and Plant Health Inspection Service (APHIS) office in Augusta at 1.866.487.3297.

Sincerely,

David T. Handley
Vegetable and 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
Biddeford 6 0 42 5-day spray interval on silking corn for CEW
Bowdoinham 2 3 1 2% 6-day spray interval on silking corn for CEW
Cape Elizabeth I 7 0 30 79% 5-day spray interval on silking corn for CEW
Cape Elizabeth II 1 2 37 41% One spray for FAW on all corn
Charleston 0 1 1 0% No spray recommended
Corinth 0 2 1 2% No spray recommended
Dayton 1 0 1 11% No spray recommended
Hollis 1 1 0 57% One spray for FAW on pre-tassel corn
Farmington 0 0 4 One spray for FAW on silking corn
Levant 3 5 3 3% 6-day spray interval on silking corn for CEW
Lewiston I 11 2 2 4-day spray interval on silking corn for CEW
Lewiston II 0 0 62 19% One spray for FAW on all corn
Livermore Falls 3 1 1 25% 6-day spray interval on silking corn for CEW
Monmouth 1 0 17 One spray for FAW on silking corn
New Gloucester 2 1 14 18% 6-day spray interval on silking corn for CEW
Nobleboro 3 0 29 0% 6-day spray interval on silking corn for CEW
No. Berwick 1 5 0 7% One spray for ECB on silking corn
Oxford 2 0 15 19% 6-day spray interval on silking corn for CEW
Palmyra 1 6 0 0% One spray for ECB on silking corn
Poland Spring 0 3 0 7% No spray recommended
Sabattus 0 20 1 One spray for ECB on silking corn
Wales 1 2 4 One spray for FAW on silking corn
Warren 9 19 49 4-day spray interval on silking corn for CEW
Wells I 0 1 1 0% No spray recommended
Wells II 5 6 70 26% 5-day spray interval on silking corn for CEW

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:
UMaine Cooperative Extension IPM
Penn State Sweet Corn IPM
UMass Extension IPM Programs

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.

The University of Maine is an equal opportunity/affirmative action institution.

Sweet Corn IPM Newsletter No. 8 – August 12, 2016

Friday, August 12th, 2016

Sweet CornSweet Corn IPM Newsletter No. 8 – August 12, 2016

Click on photos to enlarge.

CORN PEST PRESSURE MODERATE

Fall Armyworm Numbers High in Some Sites, but Other Pest Counts are Low

SITUATION
The lack of rain continues to be the most pressing issue for vegetable growers in much of the state, as irrigation management occupies much of our time. Harvest is in full swing, and overall quality is good, although some have felt the impact of the drought with smaller ear size and poor tip fill. Insect and disease pressure remains light for this time of the season, as earworm and European corn borer populations remain very low, and fall armyworm continues to be the primary problem in most fields.

European corn borer: We are finding low numbers of moths in most locations, although it is still too early to tell if this is the start of a second generation of European corn borer. Fields in Levant, North Berwick and Palmyra exceeded the 5-moth control threshold for silking corn, but only the field in Palmyra was not already under a spray interval for corn earworm. Larval feeding damage was very light, with no fields exceeding the 15% pre-tassel threshold.

Corn earworm: Moth counts were low overall around the state, with some fields showing a decline in counts from last week, and many fields catching no moths. A 6-day spray interval for all silking corn was recommended in Biddeford, Levant, one Lewiston site, North Berwick, and one Wells site. Tropical storm season is starting to brew in the Atlantic, and should storms move up the east coast into New England, we can expect corn earworm and fall armyworm numbers to increase dramatically.

Corn Earworm Larvae

Corn Earworm Larvae, photo by David Handley

Fall Armyworm on Corn Leaf

Fall Armyworm on Corn Leaf, photo by David Handley

Fall armyworm: Moth counts continue to be spotty around the state, with some sites having few or no moths, and others having very high numbers. Fall armyworm is still a threat for many farms. Moth counts exceeded the 3-moth spray threshold for silking corn in Biddeford, Cape Elizabeth, Hollis, Lewiston, Livermore Falls, New Gloucester, Oxford, Poland Spring, and one Wells site. Fields being sprayed for corn earworm should not require additional sprays for fall armyworm. Larval feeding damage exceeded the 15% feeding injury threshold on pre-tassel corn in Cape Elizabeth, one Lewiston site and Warren.

Corn leaf aphids: Remember that aphids can become a cosmetic issue on silks and husks of corn, especially when regular sprays for earworm are not controlling them. If you have not had to spray for the major pests, check to be sure that aphids are not starting to build up on the ears.

Spotted wing drosophila: Fly numbers in traps continue to climb around the state, although slowly. We haven’t yet seen a big increase in populations, but nearly all of our trapping sites are now over the recommended threshold for protecting ripening fruit. We have also been finding more larvae in unsprayed berries. Berry growers should begin spraying ripening fruit to prevent infestations. For more information visit our Spotted Wing Drosophila blog.

Spotted Wing Drosophila Larva in Blackberry

SWD Larvae in Blackberry, photo by David Handley

Squash Vine Borer Larva

Squash Vine Borer Larva, photo by David Handley

Squash vine borer: Trap counts continue to decrease in most locations, but were still high enough in some southern and coastal locations to warrant concern. We have seen some infestations in pumpkin and winter squash this week. Wilting caused by the borers can be mistaken for drought stress. Look for tunneling holes and waste on stems near the base of the plants to determine if borers are present.

Sincerely,

David T. Handley
Vegetable and 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
Biddeford 2 0 14 8% 6-day spray interval on silking corn for CEW
Bowdoinham 0 3 0 7% No spray recommended
Cape Elizabeth I 1 0 29 15% One spray for FAW on silking corn
Cape Elizabeth II 1 1 4 58% One spray for FAW on all corn
Charleston 0 0 0 0% No spray recommended
Dayton 0 0 1 16% One spray for FAW on pre-tassel corn
Hollis 0 1 3 0% One spray for FAW on silking corn
Farmington 0 0 1 No spray recommended
Garland 0 2 2 No spray recommended
Levant 3 5 0 3% 6-day spray interval on silking corn for CEW
Lewiston I 2 2 23 1% 6-day spray interval on silking corn for CEW
Lewiston II 0 0 52 17% One spray for FAW on all corn
Livermore Falls 1 0 13 0% One spray for FAW on silking corn
Monmouth 0 0 2 2% No spray recommended
New Gloucester 1 0 12 10% One spray for FAW on silking corn
Nobleboro 1 0 1 No spray recommended
No. Berwick 2 6 0 9% 6-day spray interval on silking corn for CEW
Oxford 0 2 5 0% One spray for FAW on silking corn
Palmyra 0 5 0 0% One spray for ECB on silking corn
Poland Spring 0 1 3 4% One spray for FAW on silking corn
Sabattus 0 0 0 No spray recommended
Wales 0 0 1 1% No spray recommended
Warren 0 1 2 55% One spray for FAW on pre-tassel corn
Wells I 1 2 1 6% No spray recommended
Wells II 3 0 42 8% 6-day spray interval on silking corn for CEW

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:
UMaine Cooperative Extension IPM
Penn State Sweet Corn IPM
UMass Extension IPM Programs

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.

The University of Maine is an equal opportunity/affirmative action institution.

Sweet Corn IPM Newsletter No. 7 – August 5, 2016

Friday, August 5th, 2016

Sweet CornSweet Corn IPM Newsletter No. 7 – August 5, 2016
Click on photos to enlarge.

CORN EARWORM NUMBERS RISING

Fall Armyworm Numbers Remain High, European Corn Borer Counts Increasing

SITUATION
Most growers are struggling to keep enough water on their cornfields to keep the drought from affecting crop yield and quality. Harvest is well underway in southern Maine and quality has been good. The pest situation remains moderate, although corn earworm pressure is slowly building in parts of southern and coastal Maine. Fall armyworm continues to be the most prevalent problem, and some sites are seeing an increase in European corn borer moths.

European corn borer: Moth counts were slightly higher and more widely distributed this week suggesting that a second generation of European corn borer may be getting started. However, only one field in Sabattus exceeded the 5-moth control threshold for silking corn. Larval feeding damage was very light, with no fields exceeding the 15% pre-tassel threshold.

Corn earworm: Although moth counts rose in many locations this week, about half of our sites caught no moths. A 6-day spray interval for all silking corn was recommended in Bowdoinham, Cape Elizabeth, Charleston, Dayton and one Lewiston site. A 5-day spray interval was recommended for silking corn in Biddeford and one Cape Elizabeth site. Corn not yet in silk does not need to be protected from corn earworm. Once the silks on the ears have dried, corn earworm moths are unlikely to lay eggs on it, so sprays can be stopped at that time.

Corn Earworm Feeding on Corn

Corn Earworm Feeding on Corn, photo by David Handley

Fall Armyworm Injury on Corn Leaves

Fall Armyworm Injury on Corn Leaves, photo by David Handley

Fall armyworm: Moths continue to be caught at most sites and in very high numbers in some locations. Fall armyworm is still the major threat to silking corn for many farms, although more sites are now spraying silking corn for corn earworm. Sprays for fall armyworm on silking corn were recommended in Lewiston, Livermore Falls, Monmouth, New Gloucester, Nobleboro, North Berwick, Oxford, Poland Spring, Sabattus and Wells. Fields being sprayed for corn earworm should not require additional sprays for fall armyworm. Feeding damage exceeded the 15% feeding injury threshold in Biddeford and Cape Elizabeth. Fall armyworm larvae can be difficult to control. It is important to apply sprays when the larvae are small, and have not yet burrowed into the protection of the whorls or ear channels where it is difficult to reach them. Make sure the sprayer is providing good coverage of the leaves and that the material is getting into the whorls and emerging tassels. Consider mixing a spreader into the spray to improve distribution across the surface of the leaves.

Spotted wing drosophila: Numbers in traps are starting to creep upwards, but we haven’t yet seen a big increase in flies at most locations. Sites in Limington and Bowdoinham have caught flies above the threshold level, and sprays are recommended for any ripening fruit. We have been finding larvae in some unsprayed raspberries, so growers should be on alert for symptoms and be ready to protect fruit when any flies or larvae are found. For more information visit our Spotted Wing Drosophila blog.

Male Spotted Wing Drosophila

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

Squash Vine Borer Larva

Squash Vine Borer Larva, photo by Jeffrey Hahn, Univ. of Minnesota Extension

Squash vine borer: Moth counts have decreased significantly over the past week. Only one site in New Gloucester was over the 5-moth threshold. There is usually only one generation of this insect each year, so the threat to late-planted squash should be reduced. Stay alert for squash vine borer symptoms and protect plants if damage is seen.

Sincerely,

David T. Handley
Vegetable and 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
Biddeford 4 1 9 30% 5-day spray interval on silking corn for CEW
Bowdoinham 2 1 1 8% 6-day spray interval on silking corn for CEW
Cape Elizabeth I 3 0 39 20% 6-day spray interval on silking corn for CEW
Cape Elizabeth II 4 0 61 5-day spray interval on silking corn for CEW
Charleston 2 0 0 0% 6-day spray interval on silking corn for CEW
Dayton 3 0 3 0% 6-day spray interval on silking corn for CEW
Hollis 0 0 24 0% One spray for FAW on silking corn
Farmington 0 2 1 No spray recommended
Garland 0 0 1 3% No spray recommended
Levant 0 0 2 2% No spray recommended
Lewiston I 2 1 12 0% 6-day spray interval on silking corn for CEW
Lewiston II 1 1 11 13% One spray for FAW on silking corn
Livermore Falls 0 1 5 2% One spray for FAW on silking corn
Monmouth 0 0 8 8% One spray for FAW on silking corn
New Gloucester 0 0 11 2% One spray for FAW on silking corn
Nobleboro 0 0 4 One spray for FAW on silking corn
No. Berwick 1 4 14 0% One spray for FAW on silking corn
Oxford 0 2 4 0% One spray for FAW on silking corn
Palmyra 0 4 0 1% No spray recommended
Poland Spring 0 2 5 8% One spray for FAW on silking corn
Sabattus 1 5 1 0% One spray for ECB on silking corn
Wales 0 0 1 7% No spray recommended
Warren 0 3 0 No spray recommended
Wells I 1 0 32 10% One spray for FAW on silking corn
Wells II 0 0 40 4% One spray for FAW on 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:
UMaine Cooperative Extension IPM
Penn State Sweet Corn IPM
UMass Extension IPM Programs

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Sweet Corn IPM Newsletter No. 6 – August 1, 2016

Monday, August 1st, 2016

Sweet CornSweet Corn IPM Newsletter No. 6 – August 1, 2016
Click on photos to enlarge.

CORN EARWORM THREAT REMAINS LOW

Fall Armyworm Numbers Very High at Some Sites, Absent at Others

SITUATION
More hot and dry weather has created drought conditions in much of the state, especially in southern Maine. Cornfields that can be irrigated are doing very well, but non-irrigated fields are starting to suffer. Harvest will soon be in full swing in southern Maine. The pest situation continues to be very moderate for this time of the season, with nearly all of the pressure coming from fall armyworm, in both silking and pre-tassel corn; but some sites still have no pest threats.

European corn borer: Very low moth counts continued this week, although one site in Palmyra did exceed the 5-moth threshold for silking corn and a spray was recommended. In some years we do see a second generation of European corn borer emerge late in the season in southern Maine, but it doesn’t typically appear until September. European corn borer feeding damage was also very light this week, and no fields exceeded the 15% pre-tassel threshold.

Corn earworm: Moth counts remain very low for this time of the season. Sprays on silking corn have mostly been limited to protecting against fall armyworm and European corn borer where those have been in higher numbers. Moths were caught in seven locations this week, and all but one of those had single moths, which does not trigger a protective spray. Two moths were caught in Biddeford, placing that site on a 6-day interval for all silking corn.

Fall armyworm: Moth catches continue to be high in some sites, but low in others. It appears to be the major threat to silking corn for most locations at this time. Sprays for fall armyworm on silking corn were recommended in Biddeford, Bowdoinham, Cape Elizabeth, Dayton, Lewiston, Monmouth, New Gloucester, Nobleboro, Sabattus and Wells. As expected, feeding damage was more widely observed this week, but only exceeded the 15% feeding injury threshold at one Wells site.

Fall Armyworm on Corn Silk

Fall Armyworm on Corn Silk, photo by David Handley

Aphids on Corn Ear

Aphids on Corn Ear, photo by David Handley

Corn leaf aphids: Just a reminder that these insects often infest corn plants during dry spells, especially in fields that have not recently been sprayed for other pests. Colonies of bluish-green aphid can cover tassels, stalks and husks. Their waste encourages the dark, slimy, sooty mold fungus, which covers the surface of the husks. Sprays for corn earworm usually control aphids.

Spotted wing drosophila: We are catching low levels of flies in most locations this week, but only in high enough numbers at a site Limington to raise concern. We expect populations to reach damaging levels in southern Maine over the next few weeks, especially if we have some wet weather. Once we start catching 4 or more flies per week, we’ll recommend berry growers begin spraying raspberries and blueberries to protect against spotted wing drosophila infestation. For more information visit our Spotted Wing Drosophila blog.

Female Spotted Wing Drosophila

Female Spotted Wing Drosophila, photo by Christina Hillier

Two Squash Vine Borer Moths

Two Squash Vine Borer Moths, photo by Jeffrey Hahn, Univ. of Minnesota Extension

Squash vine borer alert! We continue to catch high numbers of squash vine borers in pheromone traps in southern and mid-state Maine. Counts were over the 5 moths per week spray threshold in Biddeford, Hollis, New Gloucester, and Oxford. Be alert for squash vine borer symptoms and protect squash plants if moths or damage are seen. See the 2016-2017 New England Vegetable Management Guide for control options.

Sincerely,

David T. Handley
Vegetable and 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
Biddeford 2 0 35 7% 6-day spray interval on silking corn for CEW
Bowdoinham 0 0 5 6% One spray for FAW on silking corn
Cape Elizabeth I 0 0 42 2% One spray for FAW on silking corn
Cape Elizabeth II 0 0 26 14% One spray for FAW on silking corn
Charleston 0 3 0 0% No spray recommended
Dayton 1 0 11 1% One spray for FAW on silking corn
Hollis 1 0 0 1% No spray recommended
Farmington 0 0 0 1% No spray recommended
Garland 0 0 0 2% No spray recommended
Levant 0 0 2 1% No spray recommended
Lewiston I 1 0 35 0% One spray for FAW on silking corn
Lewiston II 0 0 11 2% One spray for FAW on silking corn
Livermore Falls 0 0 0 0% No spray recommended
Monmouth 0 0 3 2% One spray for FAW on silking corn
New Gloucester 0 0 10 1% One spray for FAW on silking corn
Nobleboro 1 0 13 0% One spray for FAW on silking corn
No. Berwick 0 2 1 0% No spray recommended
Oxford 0 0 1 0% No spray recommended
Palmyra 0 5 0 1% One spray for ECB on silking corn
Poland Spring 0 2 1 1% No spray recommended
Sabattus 0 0 4 0% One spray for FAW on silking corn
Wales 1 0 0 0% No spray recommended
Warren 1 3 0 3% No spray recommended
Wells I 0 0 0 22% One spray for ECB+FAW on pre-tassel corn
Wells II 0 0 35 1% One spray for FAW on 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 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:
UMaine Cooperative Extension IPM
Penn State Sweet Corn IPM
UMass Extension IPM Programs

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.