Sweet Corn IPM Newsletter No. 10 – August 28, 2015

August 28th, 2015 11:18 AM

Sweet CornSweet Corn IPM Newsletter No. 10 – August 28, 2015
Click on photos to enlarge.

CORN EARWORM ACTIVITY INCREASING

Downy Mildew Alert for Cucurbit Crops

SITUATION
With Labor Day in sight, corn harvest will start to wind down soon. Not many fields remain that are not yet in silk. Corn earworm activity continued to increase in most locations, but not dramatically. Fall armyworm counts are spotty, being high in some sites and absent at others. European corn borer moth counts remain very low in nearly all sites. Be alert for symptoms of downy mildew in cucurbit fields.

European corn borer: Moths were caught in Farmington, Wayne and Sabattus this week, but only Sabattus caught enough moths to warrant a spray to protect silking corn, and may indicate that a second generation of European corn borer is getting underway there.

Corn Earworm Larvae

Corn Earworm Larvae, photo by David Handley

Corn earworm: Moth captures were generally higher and more widespread this week, with most silking fields now needing protection. A 6-day spray interval for corn earworm on silking corn was recommended in Biddeford, Bowdoinham, Dayton, New Gloucester, and Sabattus. A 5-day spray interval was recommended in North Berwick, Oxford, Poland Spring, Wales, Warren and one Wells site. A 4-day spray interval was recommended in Cape Elizabeth, Lewiston and one Wells site. Tropical storm/hurricane “Erica” may track our way in the coming days. If it does, corn earworm numbers may climb rapidly.

Fall armyworm: Moth counts were somewhat higher this week, but only in some locations. Silking fields in Biddeford, Cape Elizabeth, Lewiston, New Gloucester, North Berwick, Oxford, Wales, Warren, and one Wells site were over the control threshold of three moths in silking corn. However, all of these sites were also under a spray recommendation for corn earworm on silking corn, so no additional sprays were required. Larval feeding damage on young corn was fairly low, and only over the threshold of 15% in Biddeford this week.

Downy Mildew Damage on Basil Leaf

Downy Mildew Damage on Basil Leaf, photo by Bruce Watt

Downy mildew alert:
Downy mildew on pumpkins, squash, cucumbers and basil has been reported in southern New England and could quickly spread into Maine should weather conditions remain favorable, i.e. hot and humid. Downy mildew first appears as yellow polka dots on the leaves. These spots quickly turn into square brown lesions between the leaf veins. Older leaves curl upwards at the margins, and soon all the foliage in the field dies. The disease spreads and acts quickly, so if you see the yellow polka dots or brown mosaic-like lesions you need to respond immediately with an effective material to get adequate control. Check the New England Vegetable Management Guide for more details, spray materials and precautions. Jude Boucher at University of Connecticut Extension reports that growers there have been getting good results on cucurbit crops with Ranman®, Tanos® and Presidio® fungicides.

Male and Female Spotted Wing Drosophila Flies

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

Spotted wing drosophila update:
Spotted wing drosophila counts have been rising significantly in some locations this week. Traps should be set up now, if they haven’t been set already. Start protective sprays on any ripening berries once spotted wing drosophila are caught in traps, or any larvae are noticed in the fruit. Check our SWD blog for more information.

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 31 34% 6-day spray interval recommended on all silking corn
Bowdoinham 3 0 2 6-day spray interval recommended on all silking corn
Cape Elizabeth I 13 0 9 4-day spray interval recommended on all silking corn
Cape Elizabeth II 13 0 18 0% 4-day spray interval recommended on all silking corn
Dayton I 2 0 0 6-day spray interval recommended on all silking corn
Dayton II 4 0 0 6-day spray interval recommended on all silking corn
Farmington 0 2 1 6% No spray recommended
Lewiston 26 0 8 4-day spray interval recommended on all silking corn
New Gloucester 2 0 10 6-day spray interval recommended on all silking corn
Nobleboro 0 0 0 0% No spray recommended
No. Berwick 7 0 3 0% 5-day spray interval recommended on all silking corn
Oxford 7 0 4 5-day spray interval recommended on all silking corn
Poland Spring 5 0 2 5-day spray interval recommended on all silking corn
Sabattus 3 32 1 6-day spray interval recommended on all silking corn
Wales 6 0 8 2% 5-day spray interval recommended on all silking corn
Warren 6 0 20 2% 5-day spray interval recommended on all silking corn
Wayne 1 2 0 5% No spray recommended
Wells I 5 0 0 5-day spray interval recommended on all silking corn
Wells II 9 0 4 8% 4-day spray interval recommended on all silking corn

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://ag.umass.edu/integrated-pest-management/umass-extension-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.

Boosting plum production in Maine

August 26th, 2015 8:14 AM

University of Maine researchers are working to bring locally grown plums to farm stands around the state.

The two-year project — funded by the Maine Department of Agriculture, Conservation and Forestry — is identifying suitable plum varieties for Maine’s climate that would help diversify the state’s apple farms.

The project is a joint collaboration between Angela Myracle, a phytochemist and nutritional biochemist at UMaine, and Renae Moran, a tree fruit specialist with the UMaine Cooperative Extension.

The team is assessing locally grown plum varieties by evaluating crop yields, fruit quality, consumer acceptance and production costs.

“When farmers can sell fruit directly to the consumer, it’s a lot more profitable for them,” says Moran.

Moran is collecting yield measurements, assessing the plum trees and evaluating the economic feasibility of growing plums in Maine. She got involved with plum research after farmers began to show interest in growing another fruit crop in addition to apples.

Plums were the perfect candidate.

Currently, the team is harvesting different plum varieties — grown at Highmoor Farm in Monmouth — for sensory testing, which will allow the researchers to see how consumers will perceive the fruit based on appearance, taste and texture. The last testing had approximately 100 participants.

Leading the sensory testing is Zakkary Castonguay, a master’s student in food science and human nutrition.

Castonguay’s research project is focused on the consumer acceptability and phytonutrient assessment of locally grown Maine plums. He is measuring the bioactive constituents found in plums to determine if local, tree-ripened plums have greater health benefits.

“Plums are a very low calorie snack. They are a good source of fiber and are a very good source of Vitamin C and potassium,” Myracle says. “Beyond just the basic nutrients that you hear about, they are just a good fruit that encourages people to eat the recommended number of fruits and vegetables a day.”

By assessing the phytonutrient content of the plums, the researchers are able to better market the fruit, Castonguay says.

“We don’t want to recommend a variety to a farmer that grows well, but doesn’t sell well,” Myracle says.

The majority of plums found in Maine are shipped long distances and are harvested unripe, compromising quality. Growing plums in Maine could bring in extra income for farmers, as well as decreasing transportation costs by selling the plums locally, Myracle says.

Myracle also hopes that the project will help farmers diversify their farms with fruit that could be harvested during peak tourist season.

“By the time apple season rolls around, the tourist have already left. So the potential market for apples is decreased,plums are ready during the peak tourist season” Myracle says.

“As a Mainer, I find it essential that we continue to increase the state’s economic success and we can do this by determining which plums are enjoyed by consumers as well as which plums can be grown in our local climate,” Castonguay says.

Contact: Amanda Clark, 207.581.3721

Spotted Wing Drosophila Update: August 24, 2015

August 24th, 2015 1:49 PM

SPOTTED WING DROSOPHILA UPDATE: AUGUST 24, 2015

Click on photos to enlarge.

David Handley, Vegetable and Small Fruit Specialist; James Dill, Pest Management Specialist; Frank Drummond, Professor of Insect Ecology/Entomology

Male and Female Spotted Wing Drosophila

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

Spotted wing drosophila captures have been rising significantly in some locations this week. Although the number of flies caught has been quite variable from site to site, the significant increase in populations suggests that numbers will continue to rise as more food becomes available. Therefore, the threat of infestation to any soft fruit or berries in the field is now very high.

The highest numbers of flies were caught in traps in Limington, Buxton, Dresden, Bowdoinham and Nobleboro. Lower fly counts were found in Wells, Springvale, Limerick, Poland Spring, Monmouth and Fayette.

SWD traps should be set up in fields now, if you haven’t already. Start protective sprays on any berries that have begun to ripen once spotted wing drosophila are caught in traps, or any larvae are noticed in the fruit. Look for fruit flies hovering around fruit and symptoms of premature fruit decay.

Present warm and humid weather conditions are very good for fruit fly development; and with late fruit now ripening, abundant food will allow them to reproduce rapidly. Frequently repeated insecticide sprays (1 to 2 times per week) are often needed to prevent infestations once the insect is present in a field.

drosophila trap

Drosophila Trap, photo by David Handley

A Simple Monitoring Trap for Spotted Wing Drosophila:
The trap body is made from a 16 ounce red plastic cup (we use Solo Brand P16RLR). You’ll need one that has a tight fitting lid (we use Solo Brand 626TS). Using a 1/8” hole punch (available through art suppliers), punch about 15 holes in a row around the cup just under the lip about 1/2” apart. Leave about 2” of the diameter of the rim with no holes so that liquid can be poured in and out. Punch a second row of holes just under the first row, to give you a total of 30, 1/8” holes. Use a black permanent marker to paint a 1/2” wide black strip around the cup under the rim, right over the holes you punched. To support the trap, cut a wooden tomato stake down to about 30”. Attach a 4” or larger hose clamp near the top of the stake to act as a cup holder for the trap. (We just punched a hole in the metal band of the hose clamp and attached it to the stake with a flat-headed wood screw.) Place the trap holder in a shady, moist place in or near the fruit planting, with the cup height about 18” off the ground. Fill the trap with 4 to 6 ounces of apple cider vinegar, water + sugar + yeast, or whatever bait you prefer. It is best to add a few drops of unscented soap to break the surface tension of the liquid. Place the lid on the cup to keep rain and critters from getting in, and place the trap in the holder. Adjust the hose clamp so that the trap fits in snugly but the trap holes are not covered up. Empty and re-bait the trap every week. Do not pour out the old bait on the ground near the trap, as this will draw flies away from it.

Based on what we know so far about this pest, here again are our six rules for managing spotted wing drosophila.

  1. Monitor for the flies with traps, and for the larvae in fruit.
  2. Spray regularly and often once flies have been found in the field (1-2/week).
  3. Harvest fruit regularly and often; do not leave any ripe/rotten fruit in the field.
  4. Sort fruit at harvest; do not leave any soft fruit in the container to be sold.
  5. Chill all fruit immediately after harvest to 38ºF (or as close as you can) for at least 12 hours to slow development of any eggs or larvae.
  6. Prune the planting to open up the canopy and create dry, light conditions.

Characteristics of Insecticides for Spotted Wing Drosophila Control

Trade Name Days to Harvest
Blueberry
Days of Residual
Assail® 1 5-7
Malathion 1 5-7
Mustang Max® 1 7
Bifenture® 1 (3 raspberry) 7
Brigade® 1 (3 raspberry) 7
Danitol® 3 7
Exirel® 3 (not for raspberry) 5-7
Delegate® 3 (1 raspberry) 7
Entrust® 3 (1 raspberry) 3-5

For more information on identifying spotted wing drosophila (SWD) and updates on populations around the state, visit our SWD blog.

Other SWD sites include:
Michigan State University’s website,
Pennsylvania State University’s SWD website, and
University of New Hampshire’s SWD web page.

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

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 21, 2015

August 21st, 2015 1:26 PM

Sweet CornSweet  Corn IPM Newsletter No. 9 – August 21, 2015
Click on photos to enlarge.

MODERATE CORN EARWORM ACTIVITY

Fall Armyworm Counts Lower in Some Fields this Week

SITUATION
Corn earworm activity is more widespread around the state this week, but numbers are still moderate for this late in the season. While fall armyworm counts are down in many locations, it is still a threat to both silking and young cornfields. European corn borer moth counts were very low in nearly all sites. Reports of bird damage have started coming in, as species such as black birds begin flocking and looking for food.

European corn borer:  Only a trap in Nobleboro caught any European corn borer moths this week, although there were enough at that site to recommend a spray to protect silking corn. Feeding damage on younger corn was only found at two of our most northern sites, but did not exceed the 15% threshold.

Corn earworm:  Moth captures were lower in some locations; but the distribution was wider this week, as more sites are now under a spray recommendation for silking corn. A 6-day spray interval for corn earworm on silking corn was recommended in Biddeford, Farmington, Levant, North Berwick, Oxford, Palmyra, Poland Spring, Sabattus, and one site in Wells. A 5-day spray interval was recommended in Charleston, Garland, and New Gloucester. Tropical storms are now starting to brew in the south Atlantic. When these track up the east coast to Maine, they can bring up lots of earworm moths into the state to threaten late silking corn.

Corn Earworm Moth

Corn Earworm Moth, photo by David Handley

Fall Armyworm Moths

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

Fall armyworm:  Moth counts were mostly lower this week, but high enough to be the major threat to silking corn at several locations. Feeding damage on young corn was also lower this week, as growers have been catching up with sprays on younger fields. Silking fields in Auburn, Biddeford, Cape Elizabeth, Dayton, Garland, Lewiston, New Gloucester, and Wells were over the control threshold of three moths in silking corn. Sprays specifically for fall armyworm were recommended in Auburn, Cape Elizabeth, Dayton, Lewiston and Nobleboro. Other sites were under a spray interval for corn earworm, so no additional sprays were required. Larval feeding damage was over threshold of 15% on corn in Cape Elizabeth, New Gloucester, North Berwick, Oxford, and Poland Spring this week.

Birds:  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. From there they will often move in to younger fields. For information on birds and management options, you may call the Animal and Plant Health Inspection Service (APHIS) office in Augusta at 1-866-487-3297.

Pesticide disposal:  The Maine Board of Pesticides Control (BPC) and the Maine Department of Environmental Protection will offer free disposal of banned or unusable pesticides in October. Collection will occur at sites in Presque Isle, Bangor, Augusta and Portland. To qualify, people must register by September 25, 2015. Registration is mandatory; drop-ins will not be permitted. To register and get important information about the temporary storage and transportation of obsolete pesticides, go to the BPC web site at:  http://www.thinkfirstspraylast.org, or call 207-287-2731.

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
Auburn 0 0 21 12% One spray recommended for FAW on silking corn
Biddeford 2 0 9 2% 6-day spray interval recommended on all silking corn
Cape Elizabeth I 0 0 9 0% One spray recommended for FAW on silking corn
Cape Elizabeth II 0 0 27 27% One spray recommended for FAW
Charleston 4 0 0 0% 5-day spray interval recommended on all silking corn
Dayton 0 0 3 0% One spray recommended for FAW on silking corn
Farmington 3 0 1 6-day spray interval recommended on all silking corn
Garland 7 0 7 0% 5-day spray interval recommended on all silking corn
Levant 3 0 0 2% 6-day spray interval recommended on all silking corn
Lewiston 0 0 8 One spray recommended for FAW on silking corn
New Gloucester 7 0 5 26% 5-day spray interval recommended on all silking corn
Nobleboro 0 8 0 0% One spray recommended for ECB on silking corn
No. Berwick 2 0 2 19% 6-day spray interval recommended on all silking corn
Oxford 2 0 1 26% 6-day spray interval recommended on all silking corn
Palmyra 3 0 0 8% 6-day spray interval recommended on all silking corn
Poland Spring 2 0 0 32% 6-day spray interval recommended on all silking corn
Sabattus 3 0 0 0% 6-day spray interval recommended on all silking corn
Wales 1 0 2 2% No spray recommended
Wayne 0 0 0 8% No spray recommended
Wells I 0 0 0 0% No spray recommended
Wells II 3 0 9 12% 6-day spray interval recommended on all silking corn

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

IPM Web Pages:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://ag.umass.edu/integrated-pest-management/umass-extension-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.

Sweet Corn IPM Newsletter No. 8 – August 14, 2015

August 14th, 2015 1:17 PM

Sweet CornSweet Corn IPM Newsletter No. 8 – August 14, 2015
Click on photos to enlarge.

CORN EARWORM NUMBERS RISING

Fall Armyworm Counts High in Many Fields

SITUATION
Corn earworm pressure has increased in some locations this week, although fall armyworm continues to be a more important threat at other sites. European corn borer moths are also on the increase at a few sites and could threaten late silking corn. Recent much needed rain has helped late corn development, although some fields would benefit from more moisture.

European corn borer: At sites in Nobleboro, Sabattus and Wayne, where a second generation of European corn borer may be getting underway, moth counts were over the threshold of 5 moths for silking corn. At all other sites moth counts were very low this week. Feeding damage on younger corn was only found at our most northern sites, but did not exceed the 15% threshold.

Corn earworm: Moth captures rose in many, but not all, locations this week; with the highest counts still in the southern and coastal sites. A 6-day spray interval for corn earworm on silking corn was recommended in Auburn, Bowdoinham, Charleston, Levant, Oxford, and Palmyra. A 5-day spray interval was recommended in Biddeford and Garland. A 4-day spray interval was recommended in one of the two Cape Elizabeth and Dayton sites, and in Warren. Predicted warmer night temperatures and weather fronts moving in from the southwest next week could bring increased earworm activity.

Corn Earworm Feeding on Corn

Corn Earworm Feeding on Corn, photo by David Handley

Fall Armyworm on Corn Silk

Fall Armyworm on Corn Silk, photo by David Handley

Fall armyworm: Moth counts continue to be high at many, but not all, sites this week. Larval feeding damage is also high in some fields, although most growers have been able to do a good job of controlling it. Silking fields in Auburn, Biddeford, Cape Elizabeth, Dayton, New Gloucester, Nobleboro, Warren and Wells were over the control threshold of three moths in silking corn. However, sprays specifically for fall armyworm were only recommended in New Gloucester, Nobleboro and Wells; as the other sites were also under a spray recommendation for corn earworm, so no additional sprays were needed. Larval feeding damage exceeded the threshold of 15% on younger corn only in Biddeford and Warren this week.

Squash vine borer: Very few moths were caught in our traps this week. No sites exceeded the threshold of five moths.

Picnic beetles can become a problem during the late summer on silking corn. The beetles are about 1/4 inch long, and black with orange spots. They are often found on plants that are infested with European corn borer or fall armyworm, feeding on sap at entry and exit holes. They may also feed on the silks. While this does little damage, customers object to finding the insects in their bags. Sprays to control corn earworm should provide control of these beetles when they are found.

Sap beetle on strawberry

Picnic Beetle (left) on Strawberry, photo by James Dill

Male Spotted Wing Drosophila

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

Spotted wing drosophila (SWD) update: Fly counts are starting to rise in our traps around the state, indicating that berry crops and soft fruit may be threatened. Sprays to control drosophila should start when flies are first found in a field, and continue on a regular schedule until harvest is complete. For more information visit our SWD 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
%Feeding
Damage
Recommendations / Comments
Auburn 2 0 21 1% 6-day spray interval recommended on all silking corn
Biddeford 6 0 23 55% 5-day spray interval recommended on all silking corn
Bowdoinham 2 0 0 6-day spray interval recommended on all silking corn
Cape Elizabeth I 0 0 17 5% One spray recommended for FAW on silking corn
Cape Elizabeth II 18 0 27 4-day spray interval recommended on all silking corn
Charleston 3 0 0 0% 6-day spray interval recommended on all silking corn
Dayton I 0 0 0 0% No spray recommended
Dayton II 16 0 17 0% 4-day spray interval recommended on all silking corn
Garland 7 0 2 1% 5-day spray interval recommended on all silking corn
Farmington 1 0 0 3% No spray recommended
Levant 3 3 0 2% 6-day spray interval recommended on all silking corn
Lewiston 0 0 2 0% No spray recommended
New Gloucester 0 0 17 2% One spray recommended for FAW on silking corn
Nobleboro 0 48 21 0% One spray recommended for FAW+ECB on silking corn
No. Berwick 0 0 0 0% No spray recommended
Oxford 2 0 0 0% 6-day spray interval recommended on all silking corn
Palmyra 3 2 0 4% 6-day spray interval recommended on all silking corn
Poland Spring 0 0 0 0% No spray recommended
Sabattus 1 28 0 0% One spray recommended for ECB on silking corn
Wales 0 0 2 0% No spray recommended
Warren 15 0 16 25% 4-day spray interval recommended on all silking corn
Wayne 0 18 0 0% One spray recommended for ECB on silking corn
Wells I 0 2 0 0% No spray recommended
Wells II 0 0 12 11% One spray recommended 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:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://ag.umass.edu/integrated-pest-management/umass-extension-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.

Spotted Wing Drosophila Update: August 10, 2015

August 10th, 2015 12:54 PM

SPOTTED WING DROSOPHILA ALERT: AUGUST 10, 2015

Click on photos to enlarge.

David Handley, Vegetable and Small Fruit Specialist; James Dill, Pest Management Specialist; Frank Drummond, Professor of Insect Ecology/Entomology

Spotted Wing Drosophila Maggot in Raspberry

SWD Maggot in Raspberry, photo by David Handley

Spotted wing drosophila captures are becoming more widespread this week, although numbers are still quite low at most sites. The highest numbers of flies were caught in traps in Buxton (21) and Livermore Falls (19). Single female flies were caught in traps in Wells and Oxford; and two flies were caught in traps in Limington, Limerick and Springvale. According to recent research in wild blueberry fields by Frank Drummond at the University of Maine, spotted wing drosophila becomes a serious threat when 6-10 or more flies are caught in a yeast-baited trap in a week. This suggests that flies are now a threat in some locations in Maine and any berry fields where flies have been caught with ripe or near ripe fruit should be protected.

Spotted wing drosophila populations are likely to increase rapidly in the coming weeks as more food (fruit) becomes available for the flies, especially if conditions remain warm and humid. Now is the time to set out traps, if you haven’t already. Start protective sprays on any berries that have begun to ripen, once more than 4 spotted wing drosophila are caught in traps, or any larvae are noticed in the fruit. Look for fruit flies hovering around fruit and symptoms of premature fruit decay.

Spotted Wing Drosophila Trap with One Male SWD Circled

Spotted Wing Drosophila Trap, Male SWD Circled, photo by Kaytlin Woodman

Last year, populations did not reach damaging levels until September; but weather conditions can alter how quickly the flies will build up. Frequently repeated insecticide sprays (1 to 2 times per week) are often needed to prevent infestations once the insect is present in a field. Products that provide good control of drosophila on berries include spinosad (Radiant® for strawberries, Delegate® for raspberries and blueberries), Brigade®, Danitol®, malathion and Assail®. Research suggests that adding table sugar to group 4A insecticides, such as Assail®, may improve their effectiveness. The recommended rate would be 1-2 lbs. sugar per 100 gallons of spray. Please check product labels for rates, post-harvest intervals and safety precautions. Keeping fields clean of overripe and rotten fruit will also help reduce the incidence of this insect.

For more information on identifying spotted wing drosophila (SWD) and updates on populations around the state, visit our SWD blog. Other SWD sites include:

Michigan State University’s website,
Pennsylvania State University’s SWD website, and
University of New Hampshire’s SWD web page.

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

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 7, 2015

August 7th, 2015 2:16 PM

Sweet Corn

Sweet Corn IPM Newsletter No. 7 – August 7, 2015
Click on photos to enlarge.

FALL ARMYWORM CHEWS UP YOUNG CORN

European Corn Borer on the Rise

SITUATION
Warm weather has continued to push corn development, but some fields are very dry, especially in the more northern locations. Harvest is getting into full swing, and quality of ears has been very good from most reports, although size is a little smaller than typical. Fall armyworm continues to be the major threat to corn this week, as the larvae resulting from the recent influx of moths starts to feed.

European corn borer: Moth catches were still low in most locations this week, but numbers have risen significantly in a few sites, including Nobleboro, Sabattus and Wayne, suggesting that a second generation of European corn borer may be starting to emerge. Those fields were over the threshold of 5 moths for silking corn. Feeding damage on younger corn was found at four sites but did not exceed the 15% threshold.

Corn earworm: After one week with no moth captures, counts began to climb this week, mostly in more northern and coastal sites. A 6-day spray interval for corn earworm on silking corn was recommended in Cape Elizabeth, Charleston, Levant, Monmouth, Nobleboro, and Palmyra. A 5-day spray interval was recommended at another Cape Elizabeth site. Expect moth counts to continue to rise as storm fronts push north from the south or west.

Fall Armyworm on Corn Leaf

Fall Armyworm on Corn Leaf, photo by David Handley

Fall armyworm: Moth counts fluctuated only slightly at most of our sites this week, and fall armyworm continues to be the biggest threat to silking corn at most locations. Silking fields in Auburn, Biddeford, Cape Elizabeth, Dayton, Garland, Farmington, Lewiston, New Gloucester, Nobleboro, Warren and Wells were over the control threshold of three moths in silking corn. However, some of those sites, including Cape Elizabeth and Nobleboro were also under a spray recommendation for corn earworm; so no additional sprays should be needed. Larval feeding damage increased at many locations this week. Fields in Auburn, Biddeford, Cape Elizabeth, Dayton, Sabattus, Warren, and Wells exceeded the feeding damage threshold of 15% on younger corn. Fall armyworm larvae can be difficult to control. It is important to apply sprays when the larvae are still 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 down into the whorls and emerging tassels. Consider using a spreader with the pesticide to improve spray distribution across the surface of the leaves.

Squash vine borer: Moth counts continue to decrease at our trapping sites. The threshold of five moths per week in pheromone traps was exceeded only Wells.

Aphids on Corn Tassel

Aphids on Corn Tassel, photo by Kaytlin Woodman

Corn leaf aphids may infest corn plants in fields that have not recently been sprayed for other pests. Colonies of these small, bluish-green insects can nearly cover the tassels, stalks and husks. The waste aphids excrete on the plants, called “honeydew” stimulates the development of sooty mold fungus. This dark, slimy fungus coats the surface of the husks, reducing the appearance of the ears. Sprays applied for corn earworm usually control aphids. Sprays for aphids would only be recommended if sooty mold is becoming a problem.

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
Auburn 0 3 10 32% One spray recommended for FAW
Biddeford 0 0 13 61% One spray recommended for FAW
Bowdoinham 1 0 0 0% No spray recommended
Cape Elizabeth I 2 0 12 42% 6-day spray interval recommended on all silking corn
Cape Elizabeth II 7 0 68 18% 5-day spray interval recommended on all silking corn
Charleston 3 0 0 0% 6-day spray interval recommended on all silking corn
Dayton I 0 0 20 54% One spray recommended for FAW
Dayton II 1 0 1 21% One spray recommended for FAW feeding damage
Garland 1 1 7 0% One spray recommended for FAW on silking corn
Farmington 0 0 7 0% One spray recommended for FAW on silking corn
Levant 2 0 0 2% 6-day spray interval recommended on all silking corn
Lewiston 0 0 7 One spray recommended for FAW on silking corn
Monmouth 3 0 0 12% 6-day spray interval recommended on all silking corn
New Gloucester 1 0 20 3% One spray recommended for FAW on silking corn
Nobleboro 2 21 7 6-day spray interval recommended on all silking corn
Oxford 0 0 0 5% No spray recommended
Palmyra 3 3 0 8% 6-day spray interval recommended on all silking corn
Poland Spring 0 0 0 0% No spray recommended
Sabattus 0 19 0 16% One spray recommended for ECB on silking corn
Wales 0 0 0 3% No spray recommended
Warren 1 0 14 50% One spray recommended for FAW on silking corn
Wayne 0 32 0 4% One spray recommended for ECB on silking corn
Wells I 0 0 0 21% One spray recommended for FAW feeding damage
Wells II 1 0 5 5% One spray recommended 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:
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 31, 2015

July 31st, 2015 1:34 PM

Sweet CornSweet Corn IPM Newsletter No. 6 – July 31, 2015
Click on photos to enlarge.

LOW CORN EARWORM, HIGH FALL ARMYWORM

Larvae Chewing on Young Corn, Moths Threaten Silking Corn

SITUATION
Hot, humid weather has sped up corn development around the state, especially where there has been adequate water from recent showers. Some fields have been damaged by wind and hail from recent storms. Corn not yet in tassel can often recover well from wind and hail damage. Be patient. Harvest is going strong in much of the state, although supply is still a bit spotty. Insect pressure for both young and silking corn continues to come primarily from fall armyworm.

European corn borer: Moth catches were very low this week, as the first generation of this insect continues to dwindle. Most sites had no moths and none exceeded the silking corn threshold of 5 moths. Feeding was only found at three sites and did not exceed the 15% damage threshold in any field.

Corn earworm: There were no trap captures of corn earworm moths this week, which is quite unusual for this time of year. Low numbers are also being reported from other New England states this week. Expect moth counts to rise again and threaten silking corn when any storm fronts arrive from the south or west.

Fall armyworm: Moth counts continue to be high at many of our trapping sites this week, making this insect the biggest threat to silking corn at this time. Silking fields in Auburn, Biddeford, Cape Elizabeth, Dayton, Garland, New Gloucester, Monmouth, North Berwick, Warren and Wells were over the control threshold of three moths caught in pheromone traps, and sprays to protect silking corn were recommended at those sites.

Squash vine borer: Moth counts were lower in most trapping sites this week, but the threshold of five moths per week in pheromone traps was exceeded in Cape Elizabeth and Wells, so sprays were recommended to protect squash and pumpkins.

European Corn Borer Entry Hole

European Corn Borer Entry Hole, photo by David Handley

Rust on Corn

Rust on Corn, photo by David Handley

Corn rust: Rust is a fungus disease that causes reddish-brown pustules to form on the leaves, stalks and husks, reducing the visual quality of the ears. Severe infections can reduce ear size, especially if they occur prior to tasseling. Typically, corn rust does not become a problem until late in the season, because it can’t overwinter in Maine and must move in from the south. A fungicide spray for rust would only be recommended if the infection were noticed in a field 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.

Male Fall Armyworm Moth

Male Fall Armyworm Moth, photo by David Handley

Late Blight on Potato Leaf

Late Blight on Potato Leaf, photo by James Dill

Late Blight Alert: Late blight has been confirmed in potato fields in Aroostook and Penobscot counties this week. Growers should be on the alert for symptoms in their fields and apply protectant fungicides as needed. The recent hot, humid weather has created ideal conditions for the development and spread of this disease.

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
Auburn 0 0 31 One spray recommended for FAW on silking corn
Biddeford 0 0 13 26% One spray recommended for FAW
Bowdoinham 0 3 1 0% No spray recommended
Cape Elizabeth I 0 0 5 10% One spray recommended for FAW on silking corn
Cape Elizabeth II 0 0 5 6% One spray recommended for FAW on silking corn
Charleston 0 0 1 0% No spray recommended
Dayton 0 0 25 7% One spray recommended for FAW on silking corn
Garland 0 0 15 0% One spray recommended for FAW on silking corn
Levant 0 0 0 1% No spray recommended
Monmouth 0 0 6 0% No spray recommended (no silking corn)
New Gloucester 0 0 37 7% One spray recommended for FAW on silking corn
No. Berwick 0 0 5 One spray recommended for FAW on silking corn
Oxford 0 1 0 1% No spray recommended
Palmyra 0 4 1 4% No spray recommended
Poland Spring 0 0 0 9% No spray recommended
Sabattus 0 1 1 10% No spray recommended
Wales 0 0 1 1% No spray recommended
Warren 0 0 3 12% One spray recommended for FAW on silking corn
Wells I 0 0 0 23% One spray recommended for FAW feeding damage
Wells II 0 0 40 11% One spray recommended 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:
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. 5 – July 24, 2015

July 24th, 2015 1:54 PM

Sweet CornSweet Corn IPM Newsletter No. 5 – July 24, 2015
Click on photos to enlarge.

HIGH FALL ARMYWORM COUNTS CONTINUE

Corn Earworm Numbers Lower this Week

SITUATION
Corn harvest is underway in southern Maine. Growth continues to be erratic, with cool night temperatures and dry conditions in much of the state. It looks as though early season supply will be spotty in many areas. Insect pressure is primarily coming from fall armyworm, as both European corn borer and corn earworm numbers have dropped off in most fields this week.

European corn borer: Moth catches dropped to very low levels this week, with most sites catching no moths and no sites exceeding the silking corn threshold of 5 moths. European corn borer feeding damage has also dropped off with only one field in Cape Elizabeth over the 15% damage threshold in a pre-tassel field. There is a chance that a second generation of European corn borer moths could emerge late in the summer to threaten late silking corn, especially in far southern Maine.

Corn earworm: Trap captures of moths were generally very low this week, perhaps due to cool night temperatures with showers and fog in many locations. A 6-day spray interval was recommended for silking cornfields in Garland, Farmington, Oxford and Wells. A 5-day spray interval was recommended for a silking field in Auburn. A 4-day spray interval was recommended for one field in Cape Elizabeth. It is likely that moth counts will rise again when warmer night temperatures return, or more storm fronts arrive from the south.

Fall Armyworm Moths

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

Fall Armyworm Eggs on Corn

Fall Armyworm Eggs on Corn, photo by David Handley

Fall armyworm: Moth counts continue to climb at our trap locations this week. Sprays to protect silking corn from egg-laying moths were recommended at most sites. Silking fields in Auburn, Biddeford, Bowdoinham, Cape Elizabeth, Dayton, Garland, Farmington, Lewiston, New Gloucester, Nobleboro, North Berwick, Oxford, Poland Spring, Wales, Warren, Wayne and Wells were over the control threshold of three moths caught in pheromone traps. The fields in Auburn, Cape Elizabeth, Farmington, Garland, Oxford and Wells were also on spray schedules for corn earworm, so no additional sprays for fall armyworm were recommended at those sites.

Squash vine borer: Moth counts indicate that the threat level to pumpkins and squash continues to be high in most locations this week. The threshold of five moths per week in pheromone traps was exceeded in Biddeford, Cape Elizabeth, and Wells.

Potato Leafhopper

Potato Leafhopper, photo by James Dill

Potato leafhopper alert: We are seeing signs of potato leafhopper in vegetable and strawberry fields this week. These small, bullet-shaped insects feed on plant sap from the undersides of leaves, causing the leaves to become curled, stunted and yellow-streaked. Beans are often the first crop to show symptoms, but other crops are also susceptible, including potatoes and strawberries. To scout for leafhoppers, brush the leaves of the plants with your hand. The small, whitish adults can be seen flying off the plant. Look for small, light green leafhopper nymphs on the underside of injured leaves. They are about 1/16 inch long. When touched, they will crawl sideways in a crab-like manner. Control options for potato leafhoppers are listed in the New England Vegetable Management Guide and the New England Small Fruit Management Guide.

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
Auburn 6 0 10 0% 5-day spray interval recommended on all silking corn
Biddeford 0 0 10 10% One spray recommended for FAW on silking corn
Bowdoinham 0 0 3 2% One spray recommended for FAW on silking corn
Cape Elizabeth I 0 1 25 One spray recommended for FAW on silking corn
Cape Elizabeth II 17 0 108 21% 4-day spray interval recommended on all silking corn
Charleston 2 0 0 0% No spray recommended (no silking corn)
Dayton 0 0 23 0% One spray recommended for FAW on silking corn
Farmington 2 0 5 0% 6-day spray interval recommended on all silking corn
Garland 2 0 5 0% 6-day spray interval recommended on all silking corn
Levant 1 0 1 3% No spray recommended
Lewiston 0 0 8 2% One spray recommended for FAW on silking corn
New Gloucester 0 0 69 0% One spray recommended for FAW on silking corn
Nobleboro 0 0 5 One spray recommended for FAW on silking corn
No. Berwick 1 0 10 0% One spray recommended for FAW on silking corn
Oxford 2 0 6 0% 6-day spray interval recommended on all silking corn
Palmyra 0 2 0 3% No spray recommended
Poland Spring 1 0 5 One spray recommended for FAW on silking corn
Wales 1 0 3 0% One spray recommended for FAW on silking corn
Warren 1 0 3 One spray recommended for FAW on silking corn
Wayne 1 0 5 6% One spray recommended for FAW on silking corn
Wells I 1 0 15 0% One spray recommended for FAW on silking corn
Wells II 2 0 9 3% 6-day spray interval recommended on all silking corn

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

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

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

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

Spotted Wing Drosophila Alert: July 20, 2015

July 21st, 2015 2:59 PM
Male and Female Spotted Wing Drosophila Flies

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

SPOTTED WING DROSOPHILA ALERT: JULY 20, 2015

Click on photos to enlarge.

David Handley, Vegetable and Small Fruit Specialist; James Dill, Pest Management Specialist; Frank Drummond, Professor of Insect Ecology/Entomology

Spotted wing drosophila (Drosophila suzukii) is a new pest that is a concern for growers of raspberries, blueberries and day-neutral strawberries. This small fruit fly is similar to those that hover around the ripe bananas in your kitchen, but this species will lay its eggs on fruit before it ripens, resulting in fruit that is contaminated with small white maggots just as it is ready to pick. Infested fruit quickly rots and has no shelf life. Spotted wing drosophila 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. Repeated insecticide sprays (1 to 2 per week) may be needed to prevent infestations once the insect is present in a field. The flies can successfully overwinter in Maine, although they may not build up to damaging levels until late summer. We have set out monitoring traps for spotted winged drosophila around the state to determine its activity in berry fields. However, these traps may not provide adequate early warning, i.e. when we find them in a trap they are probably already getting established in the field.

We have found a few spotted wing drosophila in Maine over the past week, including single flies in Buxton and Limington and two flies in a trap in Mechanic Falls. These are not yet damaging numbers. Research in Maine and other regions suggests that when 6 to 10 flies are caught in a yeast-baited trap in a week, larvae will start appearing in the fruit.

Products that provide good control of drosophila on berry crops include spinosad (Radiant® for strawberries, Delegate® for raspberries and blueberries), Brigade®, Danitol®, malathion and Assail®. Research suggests that adding table sugar to group 4A insecticides, such as Assail®, may improve their effectiveness. The recommended rate would be 1-2 lbs. sugar per 100 gallons of spray. Please check product labels for rates, post-harvest intervals and safety precautions. Keeping fields clean of overripe and rotten fruit will also help reduce the incidence of this insect.

For more information on identifying spotted wing drosophila (SWD) and updates on populations around the state, visit our SWD blog. Other SWD sites include:

drosophila trap

Drosophila Trap, photo by David Handley

Michigan State University’s website,
Pennsylvania State University’s SWD website, and
University of New Hampshire’s SWD web page.

Spotted wing drosophila populations may start to build rapidly in the coming weeks as more food (fruit) becomes available for the flies, especially if conditions remain warm and humid. Now is the time to set out traps, if you haven’t already. Start protective sprays on any berries that have begun to ripen, once more than 4 spotted wing drosophila flies are caught in a trap, or any larvae are noticed in the fruit. Look for fruit flies hovering around fruit and symptoms of premature fruit decay.

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

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.