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

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

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

Last Regular Issue for 2013

LATE SILKING CORN STILL NEEDS PROTECTION

Higher Earworm Counts in Southern and Coastal Locations

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

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

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

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

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

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

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

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

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

Sweet Corn IPM Weekly Scouting Summary

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

 

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

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

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

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

Image Description: Sweet Corn

Image Description: Corn Earworm Larvae

Image Description: Fall Armyworm Injury on Corn Leaves

Image Description: Male and Female Spotted Wing Drosophila Flies

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

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

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

LOW CORN PEST PRESSURE FOR LATE SEASON CORN

Higher Fall Armyworm Moth Counts in some Southern and Coastal Locations

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

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

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

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

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

Understanding and Managing Soils for Healthy Productive Crops: This series will offer farmers strategies to successfully manage soils for long-term productivity. It will take place on Tuesdays, 6:00 PM to 8:00 PM on October 1, 8, 15, 22 and 29, at the Knox and Lincoln Counties Cooperative Extension Office, 377 Manktown Road, Waldoboro, Maine. Cost is $40 per person for the series, or $10 per session. Contact Mark Hutchinson at 207.832.0343 or mhutch@maine.edu for more information, or visit the UMaine Cooperative Extension Agriculture Programs website.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

 

Sweet Corn IPM Weekly Scouting Summary

 

Location CEW
Moths
ECB
Moths
FAW
Moths
Recommendations / Comments
Auburn 2 0 0 6-day spray interval recommended on all silking corn
Biddeford 0 0 10 One spray recommended for FAW on all silking corn
Cape Elizabeth I 1 0 10 One spray recommended for FAW on all silking corn
Cape Elizabeth II 1 3 7 One spray recommended for FAW on all silking corn
Charleston 4 1 1 5-day spray interval recommended on all silking corn
Dayton I 2 3 3 6-day spray interval recommended on all silking corn
Dayton II 4 2 0 5-day spray interval recommended on all silking corn
Farmington 0 4 0 No spray recommended
Garland 0 3 1 No spray recommended
Levant 0 2 0 No spray recommended
Lewiston 0 0 No spray recommended
Monmouth 1 1 3 One spray recommended for FAW on all silking corn
New Gloucester 1 7 One spray recommended for ECB on all silking corn
Nobleboro 0 6 4 One spray recommended for FAW+ECB on all silking corn
No. Berwick 3 6 6-day spray interval recommended on all silking corn
Oxford 0 1 0 No spray recommended
Palmyra 0 1 0 No spray recommended
Sabattus 0 6 2 One spray recommended for ECB on all silking corn
Wales 0 1 1 No spray recommended
Warren 0 1 11 One spray recommended for FAW on all silking corn
Wayne 0 2 0 No spray recommended
Wells I 0 0 0 No spray recommended
Wells II 1 3 7 One spray recommended for FAW on all silking corn

 

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

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

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

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

 

Image Description: Sweet Corn

Image Description: Corn Harvester

Image Description: European Corn Borer Moth

Image Description: Male Fall Armyworm Moth

Image Description: Spotted Wing Drosophila on Raspberry

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

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

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

CORN PEST PRESSURE INCREASING IN SOUTHERN AND COASTAL REGIONS

Higher Moth Counts Require Tighter Spray Schedule for Silking Corn

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

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

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

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

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

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

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

 

Sweet Corn IPM Weekly Scouting Summary

 

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

 

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

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

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

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

Image Description: Sweet Corn

Image Description: Corn Earworm Moth

Image Description: Adult Fall Armyworm

Image Description: Spotted Wing Drosophila Larvae in Raspberry

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

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

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

ANOTHER WEEK OF LOW PEST PRESSURE

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

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

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

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

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

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

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

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

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

 

Sweet Corn IPM Weekly Scouting Summary

 

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Auburn 0 1 0 2% No spray recommended
Biddeford 0 1 6 16% One spray recommended for FAW
Cape Elizabeth 2 2 2 26% 6-day spray interval recommended on all silking corn
Charleston 6 0 0 2% 5-day spray interval recommended on all silking corn
Dayton I 0 0 6 3% One spray recommended for FAW
Dayton II 0 0 0 1% No spray recommended
Farmington 0 0 0 0% No spray recommended
Garland 3 1 0 3% 6-day spray interval recommended on all silking corn
Levant 3 1 1 3% 6-day spray interval recommended on all silking corn
Lewiston 0 0 1 1% No spray recommended
Monmouth 5 0 2 1% 5-day spray interval recommended on all silking corn
New Gloucester 1 2 0 1% No spray recommended
Nobleboro 1 1 0 12% No spray recommended
No. Berwick 2 1 0 3% 6-day spray interval recommended on all silking corn
Palmyra 0 1 0 4% No spray recommended
Sabattus 0 0 0 0% No spray recommended
Wales 2 0 0 6-day spray interval recommended on all silking corn
Warren 1 0 0 5% No spray recommended
Wells 0 0 1 8% No spray recommended

 

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

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

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

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

Image Description: Sweet Corn

Image Description: Fall Armyworm on Corn Silk

Image Description: Aphids on Corn Tassel

Image Description: Late Blight on Tomato Leaf

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

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

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

CORN PEST PRESSURE REMAINS LIGHT IN MOST FIELDS

Corn Earworm, Fall Armyworm & European Corn Borer Damage Low

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

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

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

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

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

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

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

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

Sweet Corn IPM Weekly Scouting Summary

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

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

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

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

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

Image Description: Sweet Corn

Image Description: European Corn Borer Entry Hole

Image Description: Fall Armyworm Eggs on Corn

Image Description: Plectosporium blight on pumpkin

Image Description: Male Spotted Wing Drosophila

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

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

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

A FAIRLY QUIET WEEK FOR CORN PESTS

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

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

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

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

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

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

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

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

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

Sweet Corn IPM Weekly Scouting Summary

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

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

IPM Web Pages:
http://extension.umaine.edu/ipm/

http://www.pestwatch.psu.edu/sweet_corn.htm

http://www.umass.edu/umext/ipm/

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

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

Image Description: Sweet Corn

Image Description: European Corn Borer Larva on Ear

Image Description: Corn Earworm Feeding on Corn

Image Description: Potato Leafhopper

Image Description: Male and Female Spotted Wing Drosophila Flies

Sweet Corn IPM Newsletter No. 5 – July 26, 2013

Sweet Corn IPM Newsletter No. 5 – July 26, 2013
For full page print version, please see link at the bottom. Click on photos to enlarge.

CORN INSECT ACTIVITY REMAINS MODERATE

Squash Vine Borer and Spotted Wing Drosophila Pressure Increasing

SITUATION
Early corn harvest is coming into full swing in southern Maine. Maturity is variable, but overall quality looks good. The weather pattern has been limiting movement of moths into the region, so we have seen very little change in the populations of corn earworm and fall armyworm this week. A front moving in from the south this weekend may change the situation, but for now pest pressure remains moderate.

European corn borer: Moth catches in the southern parts of the state remain quite low this week. Two of the more northern sites had relatively high counts, however. Silking fields in Charleston and Palmyra were well over the threshold of 5 moths per week but the Charleston site is also on a spray schedule for corn earworm, so no additional sprays should be required. European corn borer feeding damage was over threshold in pre-tassel fields in Biddeford, Nobleboro and Warren this week.

Corn earworm:  Moths counts remain quite low in all locations this week and most locations did not require protection. A 4-day spray interval was recommended for Charleston and Garland. A 5-day spray interval was recommended for Levant. A 6-day spray interval was recommended for silking fields in Cape Elizabeth, Hollis and Farmington.

Fall armyworm:  Most sites had few or no fall armyworm moths in pheromone traps this week. The exceptions were Biddeford and New Gloucester, which both had 5 moths, exceeding the weekly threshold of three for silking corn. Neither site was under a spray interval for corn earworm so a spray was recommended for all silking corn. Single moths were caught in just three locations this week including Cape Elizabeth, Charleston and Oxford. Two moths were caught in Nobleboro. There is still relatively little fall armyworm feeding damage in younger corn fields.

Squash vine borer moths were caught in pheromone traps in Wells, Hollis, Biddeford, Gray, New Gloucester, Nobleboro and Oxford this week. The threshold of five moths per week was exceeded in Biddeford, Hollis, Gray and New Gloucester. Be aware that this pest is very active and continues to threaten summer squash, winter squash and pumpkins. See the New England Vegetable Management Guide for control options.

Spotted Wing Drosophila Alert
Captures of spotted wing drosophila are rising this week. Flies were caught in Wells, New Gloucester, Monmouth, Dresden and Warren.  Numbers at the Warren site have increased significantly, with 84 flies caught this week. The larvae of these flies can quickly destroy any soft fruit such as raspberries and blueberries. If spotted wing drosophila has been captured in your area and you have ripening berries, the crop should be protected at this time with a recommended insecticide. Regular and repeated treatments are usually needed to keep fruit from becoming infested. Visit our Spotted Wing Drosophila blog for more details.

FINAL REMINDER: Highmoor Farm Fruit and Vegetable Growers Field Day July 31, 2013
Join us for the Highmoor Farm Field Day and Summer Tour to be held on Wednesday, July 31, starting at 9:00 a.m. Please join us for the program, farm tours and lunch. Registration fee is $20 per person, including lunch, and preregistration is strongly encouraged. For more information, visit the Highmoor Farm website or call 207.933.2100. If you are a person with a disability and will need any accommodations to participate in this program, please call Pam St. Peter at Highmoor Farm, 207.933.2100 or TDD 1.800.287.8957 to discuss your needs at least 7 days prior to this event.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Auburn 2 7 0 0% 6-day spray interval recommended on all silking corn
Biddeford 1 0 5 35% One spray recommended on silking corn for FAW
Cape Elizabeth I 0 0 1 5% No spray recommended
Cape Elizabeth II 0 0 0 No spray recommended
Charleston 3 29 1 6% 6-day spray interval recommended on all silking corn
Dayton 0 0 0 7% No spray recommended
Farmington 2 0 0 4% 6-day spray interval recommended on all silking corn
Garland 0 5 0 1% One spray recommended on silking corn for ECB
Gray 0 5 0 7% One spray recommended on silking corn for ECB
Hollis 0 0 0 7% No spray recommended
Levant 0 5 0 3% One spray recommended on silking corn for ECB
Lewiston 2 0 0 5% 6-day spray interval recommended on all silking corn
Livermore Falls 0 0 0 13% No spray recommended
New Gloucester 0 0 5  7% One spray recommended on silking corn for FAW
Nobleboro 0 1 2 23% One spray recommended ECB feeding
No. Berwick 0 0 0 3% No spray recommended
Oxford 1 2 1 6% No spray recommended
Palmyra 0 15 0 1% One spray recommended on silking corn for ECB
Sabattus 3 2 0 5% 6-day spray interval recommended on all silking corn
Wales 3 1 0 6-day spray interval recommended on all silking corn
Warren 1 1 0 15% One spray recommended for ECB feeding
Wells I 0 0 0 5% No spray recommended
Wells II 1 0 0 2% No spray recommended

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

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

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

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

Image Description: Sweet Corn

Image Description: European Corn Borer on Ear of Corn

Image Description: Two Squash Vine Borer Moths

Image Description: Highmoor Farm

Sweet Corn IPM Newsletter No. 4 – July 19, 2013

Sweet Corn IPM Newsletter No. 4 – July 19, 2013

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

INSECT ACTIVITY LOW TO MODERATE THIS WEEK

Stalled Weather Pattern Means Little Change to Pest Situation

SITUATION
Most fields did not see significant rain this week; in fact some southern and northern fields are starting to run dry. The heat has pushed corn development rapidly and a couple of early fields are just ready for harvest. Some later plantings look a bit spotty, with uneven development due to the extended cool, wet weather following planting. Generally, insect activity has been light to moderate this week, with several fields not requiring any additional protection. A predicted change in the weather pattern next week may bring about some changes in pest activity as well.

European corn borer:  Moth catches have declined to very low numbers this week, with most farms having no moths in the traps. A silking field in Charleston was the exception with 19 moths, exceeding the threshold of 5 moths per week in traps, but all of this sites are also on a spray schedule for corn earworm, so no additional sprays should be required. European corn borer feeding damage was over threshold in pre-tassel fields in North Berwick and Warren this week.

Corn earworm:  Moth counts were generally low in southern Maine this week and many locations did not require protection. In the more northern sites, counts were higher, and more frequent sprays were needed on silking corn. A 4-day spray interval was recommended for Charleston and Garland. A 5-day spray interval was recommended for Levant. A 6-day spray interval was recommended for silking fields in Cape Elizabeth, Hollis and Farmington.

Fall armyworm:  A slight increase in fall armyworm moth activity was seen this week.  Single moths were caught in seven locations this week including Auburn, Biddeford, Farmington, Dayton, Nobleboro, Oxford and Wells. At one field in New Gloucester, five moths were caught, exceeding the three-moth threshold for the week, so a spray for all silking corn was recommended. We have found very little fall armyworm feeding damage in younger corn fields, but we expect that levels will be increasing soon.

Squash vine borer moths were caught in pheromone traps in North Berwick, Wells, Hollis, Biddeford, Gray, and New Gloucester this week. The threshold of five moths per week was exceeded in North Berwick, Hollis, Gray and New Gloucester. Be aware that this pest is now active and threatens summer squash, winter squash and pumpkins.  See the New England Vegetable Management Guide for control options.

Highmoor Farm Fruit and Vegetable Growers Field Day July 31, 2013
Please join us for the Highmoor Farm Field Day and Summer Tour to be held on Wednesday, July 31, starting at 9:00 a.m. Growers will have an opportunity to tour the fruit and vegetable research plots at the farm, part of the Maine Agricultural and Forest Experiment Station, and hear Extension specialists and guest speakers discuss current research on apples, grapes and vegetables. Maine State Legislators will also be on hand to offer updates on programs and legislation effecting farming in Maine.  Please join us for the program, farm tours and lunch.

Registration fee is $20 per person, including lunch and preregistration is strongly encouraged. Visit the Field Day website for more information. If you are a person with a disability and will need any accommodations to participate in this program, please call Pam St. Peter at Highmoor Farm, 207.933.2100 or TDD 1.800.287.8957 to discuss your needs at least 7 days prior to this event.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Auburn 0 0 1 6% No spray recommended
Biddeford 1 0 1 14% No spray recommended
Cape Elizabeth I 1 0 0 7% No spray recommended
Cape Elizabeth II 2 0 0 6-day spray interval recommended on all silking corn
Charleston 9 19 0 2% 4-day spray interval recommended on all silking corn
Dayton 1 0 1 4% No spray recommended
Farmington 2 0 1 1% 6-day spray interval recommended on all silking corn
Garland 11 2 0 0% 4-day spray interval recommended on all silking corn
Gray 0 1 0 3% No spray recommended
Hollis 2 0 0 6-day spray interval recommended on all silking corn
Levant 5 0 0 1% 5-day spray interval recommended on all silking corn
Lewiston 0 0 0 0% No spray recommended
New Gloucester 0 0 5 One spray recommended on silking corn for FAW
Nobleboro 0 0 1 No spray recommended
No. Berwick 0 0 0 32% One spray recommended for ECB feeding
Oxford 0 0 1 4% No spray recommended
Palmyra 0 4 0 No spray recommended
Wales 0 1 0 6% No spray recommended
Warren 1 0 0 25% One spray recommended for ECB feeding
Wells I 0 0 0 2% No spray recommended
Wells II 0 1 1 6% No spray recommended

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

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

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

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

Image Description: Sweet Corn

Image Description: European Corn Borer Larva

Image Description: Corn Earworm Moth

Image Description: Fall Armyworm Moths

Image Description: Highmoor Farm

Strawberry IPM Newsletter No. 7 – July 15, 2013

Strawberry IPM Newsletter No. 7 – July 15, 2013

RENOVATION AND WEED MANAGEMENT ISSUE

Spotted Wing Drosophila, White Grubs Threaten Berries this Summer

The winter of 2012-2013 gave us a cold, snowless start that resulted in some winter injury in exposed strawberry fields. But good snow cover later in the winter kept damage from being severe in most locations. Good growing conditions early in the spring got plants off to a quick start with a few frosts to threaten early blooming varieties. Rain during much of the bloom period raised concerns about pollination, but going into harvest the crop looked pretty good. Unfortunately, the weather just couldn’t cooperate for much of the harvest season, with heavy rain and very hot, humid conditions, especially on weekends, which kept many of the u-pick customers at home. Pickers did come out during the short intervals of decent weather and saved the harvest from being a big loss; and pre-picked sales were good, but for most farms the end result was a season that was only fair. Timely fungicide sprays through the rain provided good protection in most fields, as gray mold was kept to a minimum in spite of all the moisture. Foliar diseases, such as powdery mildew and leaf spot began to show up towards the end of the season. Insect pressure was generally light, although some fields were weakened but white grubs feeding on plant roots.

Don’t forget about your strawberries after harvest.  Follow the recommended renovation steps listed below as soon after harvest as possible; and continue to scout for and manage disease, insect and weed problems as they arise. Some of the more common issues to be alert for during the summer are listed below.

DISEASES:  Foliar diseases should be monitored in your fields by regularly examining leaves. All of the common leaf diseases were present in fields this spring and we should expect that they will continue to be a problem through the summer. The most common summer diseases are powdery mildew, leaf spot and leaf scorch. Fungicides available for these diseases include captan, Topsin-M®, Cabrio®, Pristine® and Abound®. See the New England Small Fruit Management Guide for detailed descriptions of these diseases and their management.

Black root rot is a disease complex which can be brought on by a combination of problems, including nematodes, soil fungi (Rhizoctonia, Pythium), herbicide carryover, and soil compaction. Plants become weak and may wilt and die. Roots on affected plants are black and poorly developed. This tends to be a problem in fields that have been in strawberries constantly for many seasons, and in fields that are under stress in other ways, such as winter injury. Rotating fields to crops other than strawberries for at least three years is an important management strategy for black root rot. Improving soil drainage and breaking up hardpans in the soil may also help. Pre-plant root dips with azoxystrobin (Abound®) may also reduce incidence of black root rot in some fields.

INSECTS: If black vine weevils or strawberry root weevils are a problem in a strawberry field that you would like to carry over, bifenthrin (Brigade®, Bifenture®) can be applied when adult feeding is noticed (usually until mid-late July). Look for notching along the leaf edges and the presence of the black or brown snout beetles. Applications should be made at night when these insects are active, and the highest rate of the insecticide should be used. For control of the grubs a soil drench of Platinum® (thiamethoxam) insecticide should be applied during the fall and/or early spring when the grubs are active in the soil. This product has a 50 day pre-harvest interval and may also be used as a pre-plant or planting treatment for root weevils. Parasitic nematodes such as Heterorhabditis bacteriophora or Steinernema feltiae can also be applied to provide control of root weevil grubs in late August. Nematodes require specialized handling and application. Contact us or talk with one of the suppliers for more details. See the New England Small Fruit Management Guide for sources.

White grubs have been a problem in some fields over the past few seasons.  The grubs may be the larvae of several species of scarab beetles, including June beetles, rose chafers, Japanese beetles, Asiatic garden beetles and European chafers. The beetles lay their eggs in June and July and the grubs feed on the roots of strawberries from July through mid September. Affected plants will be stunted and wilted and may die during dry periods. Pulling up plants reveals that roots have been chewed off about an inch below the soil line. Sifting through the soil below the plants may reveal the whitish crescent-shaped grubs which can range in size from 3/8 inch to almost 1 ½ inches long, with six legs near the head and a swollen rear-end. The two most effective periods to treat plantings for grubs are in the spring prior to when they pupate (May) and in the late summer when the next generation is actively feeding (late August). Materials should be applied with plenty of water to moist soil to be sure they reach the root zone. Materials currently registered for control of grubs include Platinum® and Admire Pro®. Parasitic nematodes can also provide control of grubs and should be applied with similar timing. Nematodes are very sensitive to ultraviolet light and dehydration and must be applied with lots of water. See the New England Small Fruit Management Guide for sources of parasitic nematodes.

Strawberry rootworm (not root weevil) is a small (1/8″) dark brown to black beetle which feeds on strawberry foliage, causing it to look skeletonized. The small larvae feed on strawberry roots, further weakening the plant. Adult feeding damage on the leaves usually occurs in late July through August. Heavy rootworm feeding weakens strawberry plants so control is warranted when injury is noticed.

Keep a lookout for potato leafhoppers, which can weaken strawberry plants and spread disease. The potato leafhopper does not overwinter in Maine, but must fly in from southern states. These small, bullet-shaped insects feed on plant sap from the undersides of leaves, causing the leaves to become curled, stunted and yellow-streaked. Symptoms are often first noticed in new strawberry plantings, but leafhoppers will also infest older plantings and a variety of vegetables, flowers and fruit crops. To scout for leafhoppers, brush the leaves of the plants with your hand. The small, whitish adults can be seen flying off the plant. Examine the underside of some injured leaves. Look for small, light green leafhopper nymphs. They are about 1/16 inch long. When touched, they will crawl sideways in a crab-like manner. Controls for potato leafhoppers include malathion, carbaryl or Provado®.

MITES:  Two-spotted spider mites can become problems during the summer. Continue to take leaf samples for spider mites after renovation. If more than 25% of a 60-leaf sample has mites, controls should be applied. Summer is an ideal time to use predatory mites to control pest mites, because they prefer warm temperatures, and there is less chance of an insecticide spray that might kill them. Amblyseius fallacis can provide good control of two-spotted spider mites when they are released at a rate of about 10,000 mites per acre. Predator mite releases should only be made after a spider mite infestation has been found in the field. Releasing predators into a clean field will often result in them dying, due to a lack of food.  See the New England Small Fruit Management Guide for sources of predatory mites.

Cyclamen mites:  Plants showing weak growth and yellow, crinkled leaves may be infested with cyclamen mite. Cyclamen mites are very small and reside down in the crown of the strawberry plant feeding on the developing leaves. They are very hard to see, even with magnification.  Miticides such as Thionex®, Kelthane® or Portal® can be effective, but must be applied with lots of water to be sure that the material is carried down into the crowns. If you suspect you have this problem, give us a call.

WEEDS:  Weeds can become a big problem during the summer because they are often forgotten among all the other demands on our time and because of limited control options. However, the importance of good weed management should not be underestimated.  Keeping weeds under control this summer will prevent future infestations. Here’s a summary of weed control options for strawberries:

1.  Cultivation:  Following renovation, cultivation between strawberry rows can provide effective temporary control of annual weeds. Several types of cultivators are available which will work well in strawberry beds. Cultivators can also be used to help sweep runners into the plant rows.

2.  DCPA (Dacthal®):  A pre-emergent herbicide used in the early spring, late fall or after renovation. It offers good, short-term control of some annual broadleaf weeds and grasses. It is weak on ragweed, galinsoga, smartweed, shepherd’s purse and mustard. Its action will be improved if worked into the soil by irrigation or light cultivation, and it tends to work best in lighter, warmer soils. This may be used as an alternative to terbacil or napropamide when there is a high risk of plant injury from those products.

3.  Napropamide (Devrinol®):  A pre-emergent herbicide which provides good control of annual grasses, volunteer grains and some broadleaf weeds. It is typically applied just before mulching in the fall. Split applications have become popular due to the loss of other pre-emergent herbicides, e.g. half maximum rate application after renovation or in late summer after desired daughter plants have rooted, and a second half rate application once the strawberry plants are dormant. Napropamide should be activated by irrigation, rainfall or light cultivation within 24 hours of application. Repeated long-term use of this material, i.e. with no crop rotation, may eventually result in poor daughter plant establishment, due to rooting inhibition.

4.  Terbacil (Sinbar®):  An effective pre-emergent herbicide with some post-emergent activity, which should be applied at renovation time – after mowing and tilling the beds, but before new growth begins. A second application can be made in late fall, after the plants are dormant. No more than 6 oz. may be applied in a single application, and no more than 8 oz. may be applied in one season.  An example of one season’s use could be 5 oz. applied at renovation and 3 oz. applied in the late fall, the latter in addition to napropamide or DCPA. Terbacil can cause injury to strawberry plants.  It is important to determine appropriate rates for each location.

5.  Sethoxydim (Poast®): A post-emergent herbicide for control of actively growing grasses. It will not control broadleaf weeds. It should not be applied when grasses are under stress, e.g. drought, or on unusually hot, humid days. Do not use sethoxydim within six weeks of a terbacil (Sinbar®) application to avoid leaf injury.  Sethoxydim should be used in combination with a crop oil concentrate. Do not tank mix with 2, 4-D.

6.  Clethodim (Arrow®, Prism®, Select®):  A post-emergent herbicide, similar in activity to Poast®, for control of actively growing grasses. It will not control broadleaf weeds. It should not be applied when grasses are under stress, e.g. drought, or on unusually hot, humid days. Clethodim should be used in combination with a crop oil concentrate.

7.  Paraquat (Gramoxone Inteon®):  A contact herbicide for post-emergent control of most annual weeds and suppression of many perennial weeds. Paraquat will injure or kill strawberries, so applications are made between rows only, with a sprayer shielded to protect the strawberries. It should be used in combination with a nonionic surfactant. Paraquat should not be applied within 21 days of harvest or more than three times in one season.

8.  Pelargonic Acid (Scythe®):  A contact herbicide for post-emergent control of most annual weeds and suppression of many perennial weeds. Scythe® will injure or kill strawberries, so applications are made between rows only, with a sprayer shielded to protect the strawberries. This product has a relatively low toxicity and no residual soil activity. It has a strong, unpleasant odor.

9.  2,4-D Amine (Formula 40®, Amine 4):  A post-emergent herbicide effective on most broadleaf perennial weeds. It will not control grasses, nor offer any pre-emergent control.  2,4-D should be applied immediately after harvest is complete if emerged broadleaf weeds are a problem. After application, the bed should be left undisturbed for three to five days, before mowing the leaves off the plants. This allows time for the material to be taken in by the weeds. This material can also be used when the plants are dormant (late fall or early spring) to control winter annuals and biennials. Fall applications may result in injury to the strawberries if the plants are not completely dormant. Do not tank mix 2,4-D with sethoxydim (Poast®).

10.  Flumloxazin (Chateau®):  A pre-emergent herbicide for control of broadleaf weeds, including dandelion and shepherd’s purse. For use in the fall when plants are dormant for control of weeds the following spring.

11.  Pendimethalin (Prowl H20®):  A pre-emergent herbicide that may be applied as a band with a shielded sprayer between the rows of strawberries. No weed control will be provided within the plant rows, and contact of this product on the strawberry plants will cause injury. May not be applied within 35 days of harvest.

The use of herbicides alone rarely gives complete weed control. Some hand weeding will be necessary. To provide good weed control throughout the life of a strawberry bed, growers should concentrate on crop rotation and good pre-plant weed control.

Strawberry Bed Renovation Review

Bed renovation should begin as soon after harvest as possible. The earlier the beds get renovated, the more time runner plants have to develop, which means larger crowns and more flower buds for next year. Early renovation also improves weed management by tilling in many weeds before they go to seed, and can help with insect and foliar disease control by interfering with life cycles at a critical stage of development. The first step in the bed renovation process is to determine which beds should be carried over for another year and which should be plowed down and put into a crop rotation. Beds that did not suffer much from winter injury had good production and a good plant stand with no major weed, insect or disease problems should be carried over for another year.  Beds that do not meet these criteria should be plowed down and seeded to a suitable cover crop to reduce weed, insect and disease problems that have developed, and to increase soil organic matter content. Ideally, beds that are plowed down should be rotated out of strawberries for at least three years. If properly managed, crop rotation will greatly reduce pest problems and improve the vigor and longevity of strawberry beds without the need for soil fumigation.

Renovating a strawberry bed is basically a thinning process to promote healthy new growth that can support a good crop next spring. While some parts of the following renovation scheme may need to be modified for individual situations, all beds should undergo the following steps once harvest is complete.

1.  Broadleaf weed control:  If perennial broadleaf weeds such as dandelion, shepherd’s purse, daisy or goldenrod are a problem and/or a high population of annual broadleaf weeds such as lambsquarters, sorrel or pigweed are present, hand-pull as many as possible, especially within the plant rows, and/or apply 2,4-D amine (Formula 40®).

2.  Leaf mowing:  Four to five days following the 2,4-D application (or immediately if 2,4-D was not applied) mow off the leaves of the strawberries about 1 ½ inches above the crowns. If the planting is weak, it is recommended that this step of the renovation process be skipped.

3.  Fertilization:  Apply 40 to 60 pounds of actual nitrogen per acre (use the higher rate on sandy soils and fields where growth has been weak). Phosphorus and potassium applications should be made according to soil test recommendations. Soil testing kits and information are available from your county Cooperative Extension office.

4.  Plant thinning:  For the single matted row system, strawberry plant rows should not be any wider than 24 inches. After mowing off the leaves, till the sides of the rows to narrow the beds back to a width of 12 to 18 inches. Use the wider setting for varieties that tend to throw few runners or any fields experiencing drought stress.  Set the tiller so that it incorporates the mowed leaves and spreads about one inch of soil over the remaining crowns at the same time. This will reduce leaf disease and mite problems, and help stimulate new root growth on the remaining plants.

5.  Pre-emergent weed control:  To control annual weeds, apply terbacil (Sinbar® 80WP) according to label directions (2 to 6 oz. per acre). Be sure to follow all label precautions. To avoid plant injury, do not use terbacil if you do not intend to mow off the leaves. Napropamide (Devrinol®) or DCPA (Dacthal®) may be used as an alternative to terbacil at this time, as described below. If you are not using herbicides, regular cultivation, before weeds are more than 2” tall, will be needed throughout the summer.

6.  Subsoiling:  Soil compaction caused by tractor and picker traffic in the field can cause soil drainage problems and interfere with good root development. Using a subsoiling blade between the rows will break up compacted layers of soil and improve water infiltration. Subsoiling is best done late in the renovation sequence to prevent interference from straw and crop residues.

7.  Irrigation:  To encourage rapid plant growth and get the most out of fertilizers and herbicides, irrigate the beds regularly. Strawberries will grow best if they receive 1 ½ inches of water per week during the growing season.

Don’t forget your plants once these renovation steps are completed. Check the strawberry fields regularly during the summer for pest problems. Finding and managing problems early can prevent major problems next spring. Pay close attention to the following items:

NUTRITION:  Following the application of 40 to 60 pounds of actual nitrogen at renovation, another 20 pounds of nitrogen should be applied in mid- to late-August to stimulate flower bud development. One way to determine the nutrient status of strawberry plants during the summer is to have a leaf tissue analysis done. Tissue analysis offers a view of what is happening within the plant, and can spot any nutrient deficiencies. In combination with regular soil tests, tissue analysis will provide a complete picture of a field’s fertilizer needs. For more information about tissue analysis contact: Analytical Lab, 5722 Deering Hall, Rm. 407, University of Maine, Orono, ME 04469-5722, telephone: 581.2945.

Pest Management for Day-Neutral Strawberries

Most of the important pests that damage June-bearing varieties can be as much or more of a problem on day-neutral types. Because day-neutral strawberries will have buds, flowers and fruit all occurring at the same time, it is critical to pay close attention to the required number of days to harvest after a pesticide application, to be sure you can safely harvest ripe fruit while still protecting buds and blossoms. Some of the more important pests are listed below, along with currently recommended pesticides and days to harvest as stated on current labels.

Spotted wing drosophila (Drosophila suzukii) is a new pest which is likely to be a concern for day-neutral strawberries, fall raspberries and blueberries.  This is a small fruit fly, similar to the type that hover around the over-ripe bananas in your kitchen. However, 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. As a result, the fruit quickly rots and has no shelf life.  This insect recently came into the U.S. from northern Asia, and infested Maine berry crops last year. It can complete a generation in under two weeks, with each adult female laying hundreds of eggs. Therefore, millions of flies can be present soon after the introduction of just a few into a field. This makes them very difficult to control, and frequently repeated insecticide sprays (3 to 5 times per week) may be needed to prevent infestations once the insect is present in a field. Spotted winged drosophila can successfully overwinter here, although it may not build up to damaging levels until late in the summer. We have set out monitoring traps for spotted winged drosophila in fruit plantings around the state to determine the activity of this pest in Maine. However, these traps are unlikely to provide early warning, i.e. when we find them in a trap they are probably already established in the field. We will be alerting growers when we find them in Maine. We have found a few spotted wing drosophila in Maine this season, but not yet in damaging numbers. Products that provide good control of drosophila on strawberries include Delegate®, Brigade®, Danitol®, and malathion. Keeping fields clean of over-ripe and rotten fruit can also help reduce the incidence of this insect. For information on identifying spotted wing drosophila and making your own monitoring traps, visit the Michigan State University’s Spotted Wing Drosophila website.

Tarnished plant bug:  This is one of the most prevalent and persistent pests of day-neutral strawberries, as summer flowering coincides with peak populations of this insect. Adult and nymph stages feed on the flowers and developing fruit, causing them to have seedy ends and other malformations. Regular insecticide applications are often required to keep the damage in check. Scout the flower clusters for adults and nymphs often to determine if controls are necessary. Insecticide products for tarnished plant bug include:

Tarnished Plant Bug

Product Days to Harvest
Brigade® 0
Pyganic® 0
Assail® 1
Dibrom® 1
Rimon® 1
malathion 3
Thionex® 4

 

Two-spotted spider mites:  Mites can become a problem during the summer when the growing conditions are warm and dry.  In addition to infesting the leaves, mites can move onto the fruit, reducing marketability. Plants that are drought-stressed, over fertilized with nitrogen, or prone to dust covering, e.g. growing beside a dirt road, are especially prone to mite infestation. Predatory mites can be an effective means to control spider mites and keep them in check over the season. Releases should only be made when spider mites are present in the field to provide the predators with a source of food. Most of the products labeled for controlling spider mites will also kill predatory mites, so do not use these products after predators have been released. Scout for mites often during the season by examining the undersides of the leaves. Control is warranted if more the 25% of leaves examined have mites.

Two-Spotted Spider Mites

Product Days to Harvest
Brigade® 0
Zeal® 1
Vendex® 1
Acramite® 1
Danitol® 2
Agri-Mek® 2
Oberon® 3
Savey® 3
Kelthane® 3

 

Potato leafhoppers, sap beetles, thrips and spittlebugs may also become problems on day-neutral strawberries, but are less frequently observed than tarnished plant bug and spider mites. Recommendations for these insects can be found in the current edition of the New England Small Fruit Management Guide.

Foliar and fruit diseases also need to be managed on day-neutral strawberries, and should be controlled in much the same way as they are for June-bearing varieties. Most of the fungicide products labeled to control gray mold, powdery mildew, leaf spot and leaf scorch have either zero or one day to harvest, so protecting blossoms at the same time as fruit is near harvest should not be a problem; but be sure to check labels carefully and schedule your sprays and harvests accordingly. Anthracnose fruit rot can be especially troublesome for day-neutral strawberries, because it grows well under warm conditions and spreads by splashing water, which is encouraged on plastic mulch. Fungicides registered for control of anthracnose include Cabrio®, Abound®, Pristine® and Switch®, all of which have zero days to harvest restriction.

Visit the 2012-2013 New England Small Fruit Management Guide online for more detailed pest information.

Reminder:  Highmoor Farm Field Day and Summer Tour will be held on Wednesday, July 31, 2013 from 9:00 a.m. to 4:00 p.m. Registration fee is $20 per person, including lunch, and preregistration is strongly encouraged. For more information, visit the Highmoor Farm website or call 207.933.2100. If you are a person with a disability and will need any accommodations to participate in this program, please call Pam St. Peter at Highmoor Farm, 207.933.2100 or TDD 1.800.287.8957 to discuss your needs at least 7 days prior to this event.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

Where brand names are used it is for the reader’s information.  No endorsement is implied nor is any discrimination intended against products with similar ingredients.  Always consult product label 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.

Image Description: Strawberries

Image Description: Powdery Mildew

Image Description: Leaf Scorch

Image Description: Black Vine Weevil

Image Description: Strawberry Root Weevil Grub

Image Description: White Grub

Image Description: Strawberry Rootworm Beetle

Image Description: Two-spotted Spider Mites

Image Description: Cyclamen Mite Damage

Image Description: Mowing Strawberry Leaves

Image Description: Strawberry Irrigation

Image Description: Sidedressed Strawberry Planting

Image Description: Male and Female Spotted Wing Drosophila Flies

Image Description: First Instar Tarnished Plant Bug Nymph

Image Description: Gray Mold on Strawberries

Sweet Corn IPM Newsletter No. 3 – July 12, 2013

Sweet Corn IPM Newsletter No. 3 – July 12, 2013

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

EARLY SILKING CORN THREATENED BY CORN EARWORM

European Corn Borer also Active, Fall Armyworm Activity Low

SITUATION
Yet more rain in southern Maine
this week has kept fields wet and slowed growth, but more early planted fields are now coming into silk and first harvest is within sight. Insect activity has increased in most locations, and any silking corn is now threatened by both European corn borer and corn earworm.    

European corn borer:  Moth catches continue to be somewhat erratic this week, but most sites had relatively low counts. Silking fields in Gray, North Berwick and Sabattus were over the threshold of 5 moths per week in traps, but all of these sites are also on a spray schedule for corn earworm, so no additional sprays should be required.  European corn borer feeding damage was over threshold in pre-tassel fields in Biddeford, Cape Elizabeth, and Warren this week. We expect to see more late fields exceeding feeding injury in later plantings in the coming week.  Sprays applied at pre-tassel tend to be more effective than whorl or tassel stage sprays, because the larvae are usually more exposed.  

Corn earworm:  Moths are now being caught at most locations, but many fields do not yet have silking corn and so are not yet threatened by corn earworm. A 6-day spray interval was recommended for early silking fields in Dayton, Gray, No. Berwick, Oxford, Sabattus and Wells. A 5-day spray interval was recommended for silking fields in Farmington, Garland, and Nobleboro, where moth counts were slightly higher. A 4-day spray interval was recommended for one silking field in Cape Elizabeth where the highest moth count of the season was found this week.  

Fall armyworm:  Single moths were caught in two locations this week (Farmington, Lewiston). At this time fall armyworm is not a threat to silking corn. We have not found any fall armyworm feeding damage in younger corn fields, but we anticipate that it will be showing up soon.

Squash vine borer moths were caught in pheromone traps in North Berwick, Biddeford, Gray, New Gloucester and Nobleboro. The threshold of five moths per week was only exceeded in North Berwick, but growers should be aware that the pest is now active and threatens summer squash, winter squash and pumpkins. See the New England Vegetable Management Guide for control options.

Late Blight:  Grower and Farm Stand Alert
Late blight has been found on potato plants in northern Maine this week. This follows recent reports of late blight in tomato and potato plantings in New York and Massachusetts and many southern coastal states. Growers should be alert to catch early symptoms and be ready to apply appropriate control measures. Typical symptoms will be water-soaked lesions on the leaves with fine, white cottony mycelium on the undersides. Infections on the stems appear as dark, almost black lesions. Visit Cornell University Cooperative Extension’s web pages for photos of tomatoes and potatoes.  Please report any suspicious symptoms to the Pest Management Office 581.3883 (1.800.287.0279), or email PMO@umext.maine.edu.   

Reminder:  Highmoor Farm Field Day and Summer Tour will be held on Wednesday, July 31, 2013 from 9:00 a.m. to 4:00 p.m. Registration fee is $20 per person, including lunch, and preregistration is strongly encouraged. For more information, visit the Highmoor Farm website or call 207.933.2100. If you are a person with a disability and will need any accommodations to participate in this program, please call Pam St. Peter at Highmoor Farm, 207.933.2100 or TDD 1.800.287.8957 to discuss your needs at least 7 days prior to this event.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Auburn 5 2 0 10% No spray recommended (no silking corn)
Biddeford 1 1 0 63% One spray recommended for ECB
Cape Elizabeth I 1 2 0 3% No spray recommended
Cape Elizabeth II 43 2 0 77% 4-day spray interval recommended on all silking corn
Charleston 14 8 0 7% No spray recommended (no silking corn)
Dayton 3 1 0 1% 6-day spray interval recommended on all silking corn
Farmington 4 1 1 5-day spray interval recommended on all silking corn
Dayton 0 0 0 0 No spray recommended
Garland 7 0 0 3% 5-day spray interval recommended on all silking corn
Gray 3 23 0 6-day spray interval recommended on all silking corn
Levant 4 2 0 0% No spray recommended (no silking corn)
Lewiston 0 0 1 2% No spray recommended
Livermore Falls 1 1 0 4% No spray recommended
New Gloucester 1 2 0 2% No spray recommended
Nobleboro 6 2 0 5-day spray interval recommended on all silking corn
No. Berwick 3 13 0 6-day spray interval recommended on all silking corn
Oxford 3 3 0 6-day spray interval recommended on all silking corn
Palmyra 0 8 0 2% No spray recommended
Sabattus 2 12 0 6-day spray interval recommended on all silking corn
Wales 0 0 0 0% No spray recommended
Warren 1 0 0 20% One spray recommended for ECB
Wells I 2 0 0 0% No spray recommended (no silking corn)
Wells II 3 4 0 4% 6-day spray interval recommended on all silking corn

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

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

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

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

 

Image Description: Sweet Corn

Image Description: European Corn Borer Trap

Image Description: European Corn Borer Larvae on Pre-tassel Stage Corn

Image Description: Corn Earworm Moth

Image Description: Late Blight on Tomato Leaf


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University of Maine Cooperative Extension


Contact Information

Cooperative Extension at Highmoor Farm
52 U.S. Route 202
Monmouth, Maine 04259-0179
Phone: 207.933.2100
The University of Maine
Orono, Maine 04469
207.581.1110
A Member of the University of Maine System