Posts Tagged ‘Highmoor Farm’

Sweet Corn IPM Newsletter No. 11 – September 1, 2017

Friday, September 1st, 2017

Sweet CornSweet Corn IPM Newsletter No. 11 – September 1, 2017

Click on photos to enlarge.

COOL NIGHTS SLOW INSECT ACTIVITY

Anticipated Storm Fronts May Increase Moth Counts Next Week

SITUATION
Cool night temperatures have slowed development of late corn, but supply and quality look good for the holiday weekend. Many farms will soon be harvesting their last plantings of the season. The cool temperatures appear to have slowed pest activity as well, although most locations still require some protection on silking corn. The remnants of the tropical storm Harvey may drop rain and moths on Maine this weekend, so we may see a different situation next week.

Fall Armyworm on Corn Silk

Fall Armyworm on Corn Silk, photo by David Handley

European corn borer:  Low moth numbers this week, with most locations having caught none, and no locations over the threshold for silking corn. Larval feeding injury on younger corn was also low, but more small larvae were seen in pre-tassel to tasseling corn.

Corn earworm:  Moth counts are fairly low for this time of year in most locations, with several sites catching no moths. However, some sites remain on a tight spray schedule for silking corn. A 6-day spray interval for corn earworm was recommended for silking fields in Garland, Monmouth and Sabattus. A 5-day spray schedule was recommended in Wells. A 4-day spray interval was recommended in Biddeford, Cape Elizabeth, North Berwick, and Poland Spring.

Fall armyworm:  Moth activity remained high at many sites, well over the 3-moth threshold for silking corn. A spray for fall armyworm on silking corn was recommended in Lewiston, Oxford Palmyra and Wales. Other sites, including Auburn, Monmouth, Cape Elizabeth, North Berwick, Poland Spring and Sabattus were also over the 3-moth threshold, but are on a spray schedule for corn earworm. Larval feeding damage in younger corn fields in Cape Elizabeth and Oxford were over the 15% injury threshold, and sprays for pre-tassel to tassel corn were recommended.

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

Bird Damage on Corn

Bird Damage on Corn, photo by David Handley

Free disposal of unusable pesticides:  The Maine Board of Pesticides Control (BPC) and the Maine Department of Environmental Protection (DEP) are sponsoring the Obsolete Pesticides Collection Program. This free program is open to homeowners, family-owned farms and greenhouses. Collections of unwanted pesticides will occur at four sites: Presque Isle, Bangor, Augusta, and Portland. Participants must pre-register by September 29, 2017Drop-ins are not permitted. To register, get details, and learn important information about the temporary storage and transportation of obsolete pesticides, go to the Maine BPC web site 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 9 0 15 4-day spray interval recommended on all silking corn
Biddeford 18 0 4-day spray interval recommended on all silking corn
Bowdoinham 0 1 0 No spray recommended
Cape Elizabeth I 14 1 22 0% 4-day spray interval recommended on all silking corn
Cape Elizabeth II 30 0 29 26% 4-day spray interval recommended on all silking corn
Charleston 0 0 0 No spray recommended
Dayton I 0 0 0 0% No spray recommended
Lewiston 1 0 5 One spray for FAW
Garland 2 1 0 6-day spray interval recommended on all silking corn
Levant 0 3 0 7% No spray recommended
Monmouth 2 1 16 6-day spray interval recommended on all silking corn
Nobleboro 1 2 2 No spray recommended
North Berwick 19 0 9 3% 4-day spray interval recommended on all silking corn
Oxford 0 0 11 15% One spray for FAW
Palmyra 0 0 3 0% One spray for FAW
Poland Spring 19 0 19 14% 4-day spray interval recommended on all silking corn
Sabattus 3 3 19 6-day spray interval recommended on all silking corn
Wales 0 0 9 One spray for FAW on all silking corn
Wayne 0 0 2 No spray recommended
Wells 4 2 1 6% 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 :
UMaine Cooperative Extension IPM
Penn State Sweet Corn IPM
UMass Extension IPM Programs

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

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

Sweet Corn IPM Newsletter No. 10 – August 25, 2017

Friday, August 25th, 2017

Sweet Corn IPM Newsletter No. 10 – August 25, 2017
Click on photos to enlarge.

INSECT NUMBERS RISE, INCREASING THREAT

Corn Earworm, Fall Armyworm, European Corn Borer Moth Counts Higher

SITUATION
Fine weather has kept corn development at a good pace, and supply is improving. Quality has been very good in fields where growers have been able to irrigate. Pests that normally emerge later in the season, such as rust and aphids are starting to show up in many fields.

European corn borer:  Moth counts continue to be spotty, with many locations having no moths, but two having counts over the threshold for silking corn. Fields in Wayne and Poland Spring were over the 5-moth threshold for silking corn. Larval feeding injury was still low, but more small larvae are starting to show up in pre-tassel corn.

Corn earworm:  Moth counts were generally higher in most locations this week, calling for a tighter spray schedule for silking corn in most fields, although a few locations had no moths, including Monmouth, Farmington, Oxford, Levant and Palmyra. A 6-day spray interval for corn earworm was recommended for silking fields in Wales and Garland. A 5-day spray schedule was recommended in Bowdoinham, Charleston, Lewiston and one Wells site. A 4-day spray interval was recommended in Auburn, Biddeford, Cape Elizabeth, one Dayton site, Nobleboro, North Berwick, and one Wells site.

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:  Similar to corn earworm, moth counts were mostly higher this week, with many sites over the 3-moth threshold for silking corn. A spray for fall armyworm on silking corn was recommended at one site in Dayton, Monmouth, New Gloucester, Oxford and Sabattus.  Other sites, including Auburn, Biddeford, Cape Elizabeth, Lewiston, Nobleboro, and Wells were also over the 3-moth threshold, but are on a spray schedule for corn earworm. Larval feeding damage in younger corn was lower this week. Fields in Biddeford, and Wells were over the 15% injury threshold, and sprays for pre-tassel to tassel corn were recommended.

Corn leaf aphids have been observed in many fields this week. Colonies of these small, bluish-green insects can cover the tassels, stalks and husks. The aphids excrete a “honeydew” on the leaves and husks, which stimulates the development of sooty mold fungus. This dark, slimy coating greatly reduces the visual appeal of the ears. Sprays applied for corn earworm usually control aphids.

Aphids on corn

Aphids on Corn, photo by Kaytlin Woodman

Rust on Corn

Rust on Corn, photo by David Handley

Corn rust:  We have also seen corn rust in many fields this week. Rust is a fungus disease that causes reddish-brown pustules to form on the leaves and husks, reducing the quality of the ears. Typically, corn rust does not become a problem until late in the season. 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 Quadris®, Bravo®, and Quilt®.

Spotted wing drosophila:  Numbers continue to increase in fields with ripe berry fruit. Regular sprays (every 5-7 days) will be needed to prevent raspberries, blueberries and day neutral strawberries from becoming infested with larvae. Visit our Spotted Wing Drosophila 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
Auburn 18 0 21 4-day spray interval recommended on all silking corn
Biddeford 13 1 22 24% 4-day spray interval recommended on all silking corn
Bowdoinham 6 0 2 5-day spray interval recommended on all silking corn
Cape Elizabeth I 28 2 19 6% 4-day spray interval recommended on all silking corn
Cape Elizabeth II 20 3 11 14% 4-day spray interval recommended on all silking corn
Charleston 4 0 2 5-day spray interval recommended on all silking corn
Dayton I 1 0 4 One spray on silking corn for FAW
Dayton II 19 0 12 8% 4-day spray interval recommended on all silking corn
Farmington 0 4 0 No spray recommended
Lewiston 6 0 9 5-day spray interval recommended on all silking corn
Garland 2 0 0 1% 6-day spray interval recommended on all silking corn
Levant 0 0 0 2% No spray recommended
Monmouth 0 0 5 1% One spray on silking corn for FAW
New Gloucester 0 67 5% One spray on silking corn for FAW
Nobleboro 8 0 9 4-day spray interval recommended on all silking corn
North Berwick 32 0 9 0% 4-day spray interval recommended on all silking corn
Oxford 0 0 5 3% One spray on silking corn for FAW
Palmyra 0 0 0 0% No spray recommended
Poland Spring 6 One spray on silking corn for ECB
Sabattus 1 1 3 One spray on silking corn for FAW
Wales 2 0 2 2% 6-day spray interval recommended on all silking corn
Wayne 1 5 0 One spray on silking corn for ECB
Wells I 9 0 3 17% 4-day spray interval recommended on all silking corn
Wells II 6 4 24 8% 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 :
UMaine Cooperative Extension IPM
Penn State Sweet Corn IPM
UMass Extension IPM Programs

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

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

Sweet Corn IPM Newsletter No. 9 – August 18, 2017

Friday, August 18th, 2017

Sweet CornSweet Corn IPM Newsletter No. 9 – August 18, 2017
Click on photos to enlarge.

COOL NIGHTS SLOW INSECT ACTIVITY  

Silking Corn Still Needs Protection in Most Fields

SITUATION
Cool nights and dry conditions have slowed corn development, and pushed expected harvests dates back, leading to a short supply of sweet corn in some areas. Expected rain over the weekend and warmer temperatures next week should help the situation. Insect pressure has been somewhat lighter this week, although most fields still require protection for silking corn.

European corn borer:  Moth counts have been spotty around the state.  Most locations continue to see no moths, but counts have increased in a few fields. Fields in North Berwick and Poland Spring were over the 5-moth threshold for silking corn, but both sites are also under a spray interval for corn earworm, so no additional sprays should be needed. Larval feeding injury was low, with most of the injury on late corn due to fall armyworm.

Corn Earworm Moth

Corn Earworm Moth, photo by David Handley

Corn earworm:  Moth counts were generally lower in most locations this week, but still high enough to warrant a tight spray schedule for silking corn in most fields. A 6-day spray interval for corn earworm was recommended for silking fields in Wayne. A 5-day spray schedule was recommended in Bowdoinham, one Cape Elizabeth site, Levant, Poland Spring and one Wells site. A 4-day spray interval was recommended in Auburn, one Cape Elizabeth site, Lewiston, New Gloucester, Nobleboro, North Berwick, Sabattus and one Wells site.

Male Fall Armyworm Moth

Male Fall Armyworm Moth, photo by David Handley

Fall armyworm:  Similar to corn earworm, moth counts were mostly lower this week, although several sites were over the 3-moth threshold for silking corn. A spray for fall armyworm on silking corn was recommended in Biddeford.  Other sites, including Cape Elizabeth, New Gloucester, Nobleboro, Poland Spring, and Wells were also over the 3-moth threshold, but are now on a spray schedule for corn earworm. Larval feeding damage in younger corn was also lower this week. Fields in Auburn, Cape Elizabeth, New Gloucester, Poland Spring and Wells were over the 15% injury threshold, and sprays for pre-tassel to tassel corn were recommended.

Potato Leafhopper

Potato Leafhopper, photo by James Dill

Potato leafhopper alert:  We are still seeing signs of potato leafhopper in vegetable and strawberry fields this week. These small, green 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. Controls for potato leafhoppers are listed in the New England Vegetable Management Guide.

Squash vine borer:  Counts were quite low this week, with no fields over the control threshold, which agrees with data from NH. There is the possibility of a second generation emerging over the next few weeks that could threaten late squash and pumpkins or attack ripening fruit.

Spotted Wing Drosophila Larvae in Blueberry

Spotted Wing Drosophila Larvae in Blueberry, photo by David Handley

Spotted wing drosophila: Numbers have been increasing over the past week, and now threaten any soft fruit in the field, such as late raspberries and blueberries. Regular sprays will be needed to prevent such fruit from becoming infested with larvae. Visit our Spotted Wing Drosophila 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
Auburn 18 0 2 47% 4-day spray interval recommended on all silking corn
Biddeford 0 0 3 2% One spray recommended for FAW
Bowdoinham 5 0 2 7% 5-day spray interval recommended on all silking corn
Cape Elizabeth I 6 1 0 20% 5-day spray interval recommended on all silking corn
Cape Elizabeth II 8 9 4-day spray interval recommended on all silking corn
Charleston 1 1 0 No spray recommended
Dayton 5 1 1 1% 5-day spray interval recommended on all silking corn
Farmington 0 0 0 5% No spray recommended
Lewiston 8 1 1 4-day spray interval recommended on all silking corn
Garland 0 2 0 3% No spray recommended
Levant 5 2 3 2% 5-day spray interval recommended on all silking corn
Monmouth 0 0 1 14% No spray recommended
New Gloucester 30 0 28 16% 4-day spray interval recommended on all silking corn
Nobleboro 12 1 3 4-day spray interval recommended on all silking corn
North Berwick 15 5 1 3% 4-day spray interval recommended on all silking corn
Oxford 0 0 1 0% No spray recommended
Palmyra 0 0 1 0% No spray recommended
Poland Spring 6 9 15 20% 5-day spray interval recommended on all silking corn
Sabattus 10 0 0 0% 4-day spray interval recommended on all silking corn
Wales 1 0 0 0% No spray recommended
Wayne 3 0 0 6-day spray interval recommended on all silking corn
Wells I 6 0 2 25% 5-day spray interval recommended on all silking corn
Wells II 9 0 11 5% 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 :
UMaine Cooperative Extension IPM
Penn State Sweet Corn IPM
UMass Extension IPM Programs

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

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

Sweet Corn IPM Newsletter No. 8 – August 11, 2017

Friday, August 11th, 2017

Sweet CornSweet Corn IPM Newsletter No 8 – August 11, 2017

Click on photos to enlarge.

CORN EARWORM THREAT INCREASES  

Fall Armyworm, European Corn Borer Also Increases

SITUATION
A little bit of rain over most of the state helped move corn along, but cooler weather recently has delayed development of younger fields. Harvest is moving into main season varieties and quality continues to look good. Corn earworm numbers are up significantly in most locations, calling for a tightening of spray intervals.

European corn borer:  Moth counts have increased in some fields this week, suggesting that a second generation of European corn borer may be getting underway in southern Maine, but feeding injury remains low, and most fields are presently being protected with sprays for corn earworm.

Corn earworm:  Moth counts increased significantly in many locations this week, requiring a tightening of spray intervals for silking corn fields. A 6-day spray interval for corn earworm was recommended for silking fields in Monmouth and one Dayton site. A 4-day spray interval was recommended in Auburn, Biddeford, Bowdoinham, one Cape Elizabeth site, one Dayton site, Lewiston, North Berwick, Poland Spring, Wales, and Wells. A 3-day spray interval was recommended at one of the Cape Elizabeth sites.

Corn Earworm Larvae

Corn Earworm Larvae, photo by David Handley

Fall Armyworm on Corn Leaf

Fall Armyworm on Corn Leaf, photo by David Handley

 Fall armyworm:  Moth counts are still fairly high, and increased at several sites. Most fields are presently under a spray interval for corn earworm, however, so the silking fields should be adequately protected. A spray for fall armyworm on silking corn was recommended in Oxford.  Other sites, including Auburn, Lewiston, Biddeford, Cape Elizabeth, Dayton, Monmouth, New Gloucester, Wales and Wells were also over the 3-moth threshold, but are now on a spray schedule for corn earworm.

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 17 0 15 46% 4-day spray interval recommended on all silking corn
Biddeford 36 1 11 6% 4-day spray interval recommended on all silking corn
Bowdoinham 11 0 0 1% 4-day spray interval recommended on all silking corn
Cape Elizabeth I 33 1 15 43% 4-day spray interval recommended on all silking corn
Cape Elizabeth II 118 3 22 38% 3-day spray interval recommended on all silking corn
Charleston 1 1 0 0% No spray recommended
Dayton I 2 0 0 6-day spray interval recommended on all silking corn
Dayton II 37 0 7 11% 4-day spray interval recommended on all silking corn
Farmington 0 0 0 0% No spray recommended
Garland 0 2 0 3% No spray recommended
Levant 5 2 3 2% 5-day spray interval recommended on all silking corn
Lewiston 24 2 9 1% 4-day spray interval recommended on all silking corn
Monmouth 3 0 6 6% 6-day spray interval recommended on all silking corn
New Gloucester 49 One spray recommended for FAW on pre-tassel corn
North Berwick 38 6 2 2% 4-day spray interval recommended on all silking corn
Oxford 1 0 4 0% One spray recommended for FAW
Palmyra 0 0 1 0% No spray recommended
Poland Spring 18 8 2 12% 4-day spray interval recommended on all silking corn
Wales 8 0 6 0% 4-day spray interval recommended on all silking corn
Wells I 8 0 6 31% 4-day spray interval recommended on all silking corn
Wells II 71 0 8 0% 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 :

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

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

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

 

Sweet Corn IPM Newsletter No. 7 – August 4, 2017

Friday, August 4th, 2017

Sweet Corn

Sweet Corn IPM Newslettter No. 7 – August 4, 2017
Click on photos to enlarge.

INCREASING CORN EARWORM ACTIVITY  

Fall Armyworm Threat Remains High in Many Fields

SITUATION
“Abnormally dry” conditions continue in much of the state, and growers are spending a lot of time keeping up with irrigation.  Harvest is progressing on early corn and overall quality looks good. Corn earworm populations have increased a bit over last week, and fall armyworm numbers are high in some fields.

European corn borer:  Moth captures were very low this week, suggesting an end to the first generation of this pest. Larval feeding activity was also very low and did not exceed threshold in any fields.

Corn earworm:  Moth counts increased moderately in most locations this week, putting most fields on a spray interval for silking corn. A 6-day spray interval for corn earworm was recommended for silking fields in Auburn, one Cape Elizabeth site, one Dayton site, Lewiston, Levant, Nobleboro, Palmyra, Poland Spring, and one Wells site. A 5-day spray interval was recommended for silking fields at one Dayton site and New Gloucester. A 4-day spray interval was recommended in Biddeford, one Cape Elizabeth site and Garland.

Corn Earworm

Corn Earworm, photo by David Handley

Fall Armyworm on Corn Silk

Fall Armyworm on Corn Silk, photo by David Handley

Fall armyworm:  Moth counts are down a bit from last week, however counts are still very high at some locations and present a significant threat to both young plants and silking corn. Most silking fields are now under a spray interval for corn earworm, which should also keep fall armyworm in check. However, in silking fields that are not currently spraying for earworm, weekly applications for fall armyworm based on the three moths caught per week threshold, may not provide adequate protection, especially under hot, dry conditions; and growers should consider more frequent applications. A spray for fall armyworm on silking corn was recommended in Sabattus.  Other sites, including Auburn, Lewiston, Biddeford, Cape Elizabeth, Dayton, New Gloucester, Nobleboro, and Wells were also over the 3-moth threshold, but are now on a spray schedule for corn earworm.

Powdery Mildew on Pumpkin Leaf

Powdery Mildew on Pumpkin Leaf, photo by Mark Hutton

Squash vine borer moths were above the spray threshold of 5 moths in Biddeford, Cape Elizabeth and New Gloucester this week. Growers with squash and pumpkins should be on the lookout for vine borer symptoms and protect squash plants if moths or damage are seen.

We are also starting to see more disease pressure in squash and pumpkins. Both powdery mildew and black rot (aka gummy stem blight) have starting appearing in pumpkin fields this week. For management suggestions check the New England Vegetable Management Guide. If you need a copy please call us, or you can find it online at: https://nevegetable.org/.

Squash Vine Borer Larva

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

Spotted Wing Drosophila Larvae in Raspberry

Spotted Wing Drosophila Larvae in Raspberry, photo by David Handley

Spotted wing drosophila:  Fly counts have been rising over the past week, and most sites are now at a level where control measures are required to prevent infestation. Blueberries, raspberries and blackberries are especially at risk, and should be sprayed at a 5- to 7-day interval to maintain clean fruit. For details, visit our Spotted Wing Drosophila 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 52 0% 6-day spray interval recommended on all silking corn
Biddeford 13 0 8 31% 4-day spray interval recommended on all silking corn
Bowdoinham 1 0 0 1% No spray recommended
Cape Elizabeth I 2 0 8 2% 6-day spray interval recommended on all silking corn
Cape Elizabeth II 9 0 21 4-day spray interval recommended on all silking corn
Charleston 0 1 1 1% No spray recommended
Dayton I 4 0 1 0% 5-day spray interval recommended on all silking corn
Dayton II 2 0 7 3% 6-day spray interval recommended on all silking corn
Farmington 0 2 0 0% No spray recommended
Garland 8 0 0 0% 4-day spray interval recommended on all silking corn
Lewiston 2 0 6 0% 6-day spray interval recommended on all silking corn
Levant 3 0 0 0% 6-day spray interval recommended on all silking corn
New Gloucester 5 0 73 0% 5-day spray interval recommended on all silking corn
Nobleboro 2 0 6 2% 6-day spray interval recommended on all silking corn
North Berwick 0 0 0 0% No spray recommended
Oxford 0 2 17% One spray recommended for FAW on pre-tassel corn
Palmyra 3 0 0 0% 6-day spray interval recommended on all silking corn
Poland Spring 2 1 0 37% 6-day spray interval recommended on all silking corn
Sabattus 1 0 6 2% One spray recommended for FAW on all silking corn
Wales 1 0 1 0% No spray recommended
Wayne 0 1 0 0% No spray recommended
Wells I 2 0 8 0% 6-day spray interval recommended on all silking corn
Wells II 0 0 0 0% No spray recommended

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

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

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

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

Sweet Corn IPM Newsletter No. 6 – July 31, 2017

Monday, July 31st, 2017

Sweet CornUniversity of Maine Sweet Corn IPM Newsletter No. 6 – July 31, 2017
Click on photos to enlarge.

FALL ARMYWORM PRESSURE INCREASES  

New Pest of Onions, Garlic and Leeks Found in Western Maine

SITUATION
Many parts of the state are experiencing very dry conditions, but corn that can be irrigated is progressing well. Corn earworm populations remain very moderate at most sites, and European corn borer numbers are also low in most fields. Fall armyworm numbers continue to rise in most fields, however. A new pest of onions, garlic and leeks has recently been found in Maine. Leek moth may become a problem for crops in the allium group.

European corn borer:  Moth captures continue to be low in nearly all locations this week. Larval feeding activity also remained under threshold. We typically see a drop in corn borer activity in the mid-summer, as the larvae from the first generation begin to pupate. However, this may lead to a second generation late in the summer, especially in southern Maine.

Corn earworm:  Moth counts remain moderate in most locations this week, with less than half of the trapping sites exceeding a spray threshold. This is less pressure than we typically see at this point in the season. A 6-day spray interval for corn earworm was recommended for silking fields in Levant, Nobleboro, Wales and one Wells site this week. A 5-day spray interval was recommended for silking fields in Garland and Poland Spring. A 4-day spray interval was recommended in Auburn and Lewiston.

Fall Armyworm Eggs on Corn

Fall Armyworm Eggs on Corn, photo by David Handley

Fall armyworm:  Moth counts have risen at nearly all trap locations this week, indicating that this pest is presently the most significant threat to corn for most growers. When more than three moths are caught in a week in silking corn, a spray is recommended to prevent larvae from infesting the ears, unless the field is under a spray interval for corn earworm. Sprays for fall armyworm on silking corn were recommended in Biddeford, Cape Elizabeth, Dayton, Farmington, New Gloucester, North Berwick, Oxford, Wayne and one Wells site this week. Auburn, Lewiston, Nobleboro and Wales were also over the 3-moth threshold, but are under a spray schedule for corn earworm.

Leek Moth is a “new” pest of allium crops, including onions, garlic, shallots and leeks. Native to Europe, it was first found in New York in 2009, and has been spreading throughout the northeast. The adult moth is ½-inch long, speckled brown with a white spot on the wings. It is active at night, so is not commonly seen. They lay eggs on the undersides of allium leaves. The larvae are small (3/8-inch) creamy yellow caterpillars that feed on the leaves, leaving translucent channels between the leaf veins. The feeding weakens the plants and allows rot organisms to move in, which can affect the quality and storage life of the bulbs. Leek moths have been caught in pheromone traps in western Maine. We do not yet have any reports of crop damage, but we recommend that you scout your allium crops and let us know if you see any suspected injury. An excellent web site has been set up for leek moth by Cornell University at:  http://web.entomology.cornell.edu/shelton/leek-moth/index.html.

Leek moth adult

Leek Moth Adult, photo by Dan Olmstead, Cornell University

Squash Vine Borer Larva

Squash Vine Borer Larva, photo by David Handley

Squash vine borer moths were above the spray threshold in Biddeford, Cape Elizabeth, and Oxford this week.

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 8 1 7 1% 4-day spray interval recommended on all silking corn
Biddeford 1 2 51 4% One spray recommended for FAW on all silking corn
Bowdoinham 0 0 0 6% No spray recommended
Cape Elizabeth I 1 0 29 2% One spray recommended for FAW on all silking corn
Cape Elizabeth II 0 41 One spray recommended for FAW on all silking corn
Charleston 0 0 2 0% No spray recommended
Dayton I 0 0 9 One spray recommended for FAW on all silking corn
Dayton II 7 0 39 4% 5-day spray interval recommended on all silking corn
Farmington 1 2 3 1% One spray recommended for FAW on all silking corn
Garland 4 0 0 2% 5-day spray interval recommended on all silking corn
Lewiston 11 0 31 1% 4-day spray interval recommended on all silking corn
Levant 2 2 0 1% 6-day spray interval recommended on all silking corn
New Gloucester 1 0 106 5% One spray recommended for FAW on all silking corn
Nobleboro 2 0 13 6-day spray interval recommended on all silking corn
North Berwick 1 1 9 5% One spray recommended for FAW on all silking corn
Oxford 1 0 15 0% One spray recommended for FAW on all silking corn
Palmyra 1 5 0 0% No spray recommended (no silking corn)
Poland Spring 4 0 1 5-day spray interval recommended on all silking corn
Wales 3 3 4 0% 6-day spray interval recommended on all silking corn
Wayne 1 0 3 4% One spray recommended for FAW on all silking corn
Wells I 0 0 11 0% One spray recommended for FAW on all silking corn
Wells II 0 0 9 2% 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:
UMaine Cooperative Extension IPM
Penn State Sweet Corn IPM
UMass Extension IPM Programs

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

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

Sweet Corn IPM Newsletter No. 5 – July 21, 2017

Monday, July 24th, 2017

Sweet CornSweet Corn IPM Newslettter No. 5 – July 21, 2017
Click on photos to enlarge.

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

INSECT PRESSURE HIGHER; PROTECT SILKING CORN

Corn Earworm & Fall Armyworm Numbers Increasing

SITUATION
High temperatures have pushed sweet corn development, compensating somewhat for earlier cool temperatures.  While European corn borer pressure has been decreasing, corn earworm and fall armyworm pressure has been increasing, posing a serious risk to fields now in silk. Synthetic pyrethroid insecticides (FRAC Group 3A) may have a short residual life under hot, sunny conditions, so recommended spray intervals should not be extended unless daily high temperatures fall below 85 degrees for 3 or more consecutive days. For those growers trying Bt-modified corn selections, it is important to note that this protection may not be adequate under very heavy fall armyworm or corn earworm pressure. When moth populations are high, Bt fields should be scouted for injury and treated if necessary.

European corn borer:  Moth captures were very low this week, and larval feeding activity is decreasing. No fields were over the recommended spray thresholds. However, fall armyworm larval feeding damage is being noticed in more fields, and is quickly become more of a threat than European corn borer.

Corn earworm:  Moth counts increased again this week, and are becoming more widely distributed. More silking fields have been put on spray schedules to protect ears from infestation. A 6-day spray interval for corn earworm was recommended for silking fields in Oxford, Sabattus, Dayton, North Berwick and one Wells site this week. A 5-day spray interval was recommended for silking fields in Auburn, Cape Elizabeth, Garland, and Poland Spring. A 4-day spray interval was recommended in Lewiston.

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 rose significantly in many locations this week, indicating that fall armyworm will be an important threat to corn in the coming days and weeks. Feeding damage was found in more fields, but has generally been low to date. Once the corn has reached the silking stage, sprays should be based on captures of moths in pheromone traps to prevent larvae from damaging the ears. If three or more moths are caught in a week in silking fields, a spray is recommended, unless the field is under a spray interval for corn earworm. Sprays for fall armyworm on silking corn were recommended in Biddeford New Gloucester, Wayne and one Wells site this week. Cape Elizabeth and Lewiston were also over the 3-moth threshold, but are under a spray schedule for corn earworm.

Spotted wing drosophila:  Fly counts have risen significantly in most of our trapping sites this week. Growers with ripening blueberries, raspberries or other soft fruit should be monitoring for flies and larvae, and should consider protecting all ripening fruit. For details, visit our Spotted Wing Drosophila blog.

Male and Female Spotted Wing Drosophila

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

Two Squash Vine Borer Moths

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

Squash vine borer moths were caught in pheromone traps in Wells, Biddeford, Cape Elizabeth, Farmington and Oxford this week. The Biddeford, Cape Elizabeth and Dayton sites were above the 5 moths per week spray threshold, and a spray was recommended. This pest remains active in much of the state. Growers with squash and pumpkins should be on the lookout for vine borer symptoms and protect squash plants if moths or damage are seen.

Sincerely,

David T. Handley
Vegetable and Small Fruit Specialist

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

 

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Auburn 5 0 0 0% 5-day spray interval recommended on all silking corn
Biddeford 0 31 12% One spray recommended for FAW on all silking corn
Cape Elizabeth I 4 0 6 0% 5-day spray interval recommended on all silking corn
Cape Elizabeth II 6 0 26 10% 5-day spray interval recommended on all silking corn
Charleston 0 0 0 0% No spray recommended
Dayton I 3 1 1 6-day spray interval recommended on all silking corn
Dayton II 1 0 1 5% No spray recommended
Farmington 1 1 2 2% No spray recommended
Garland 4 0 0 0% 5-day spray interval recommended on all silking corn
Lewiston 9 0 29 0% 4-day spray interval recommended on all silking corn
Levant 1 0 0 1% No spray recommended
New Gloucester 0 0 41 0% One spray recommended for FAW on all silking corn
Nobleboro 1 0 0 0% No spray recommended
North Berwick 3 1 1 2% 6-day spray interval recommended on all silking corn
Oxford 2 0 11 9% 6-day spray interval recommended on all silking corn
Palmyra 3 0 0 0% No spray recommended (no silking corn)
Poland Spring 6 0 0 5-day spray interval recommended on all silking corn
Sabattus 2 0 0 3% 6-day spray interval recommended on all silking corn
Wales 0 0 1 0% No spray recommended
Wayne 1 0 6 0% One spray recommended for FAW on all silking corn
Wells I 1 2 9 1% One spray recommended for FAW on all silking corn
Wells II 3 0 3 1% 6-day spray interval recommended on all silking corn

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

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

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

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

 

 

Sweet Corn IPM Newsletter No. 4 – July 14, 2017

Friday, July 14th, 2017

Sweet CornSweet Corn IPM Newsletter No. 4 – July 14, 2017
Click on photos to enlarge.

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

FALL ARMYWORM ACTIVE IN CORN FIELDS

Corn Earworm Spreading Throughout State

SITUATION
More fields are coming into silk this week and growth is looking good overall. Unfortunately, corn earworm numbers are increasing and fall armyworm has made its first appearance, threatening silking fields. Remember that applying sprays at the early tassel stage can provide good control of European corn borer and fall armyworm as they move from the whorl or tassel to the ears.

European corn borer:  Moth captures continue to be scattered and relatively low, but larval feeding activity was found in nearly all the fields we scouted. More fields were over the recommended spray thresholds with 15% of pre-tassel plants showing injury. Fields in Biddeford, Cape Elizabeth, Dayton, Nobleboro, Poland Spring, Sabattus and Wells were over threshold for pre-tassel corn so sprays were recommended. In silking corn, sprays may also be based on the number of moths caught in pheromone traps to prevent larvae from infesting the ears, but no fields were over the 5-moth threshold this week.

European Corn Borer Larvae on Pre-tassel Stage Corn

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

Corn Earworm Moth

Corn Earworm Moth, photo by David Handley

Corn earworm: Moths have been more widely distributed and in higher numbers this week, but not all locations had captures or were over threshold for silking corn. Growers with early corn should be on the alert to protect any silking fields if moths are found in the area. A 6-day spray interval for corn earworm was recommended for silking fields in North Berwick and Wales this week. A 5-day spray interval was recommended for silking fields in Cape Elizabeth and Nobleboro. When no silking corn is available, corn earworm larvae may chew large, ragged holes in the leaves, similar to fall armyworm. This should be counted in field scouting for European corn borer and fall armyworm.

Fall armyworm:  The first confirmed fall armyworm moths were captured in our pheromone traps this week, and feeding damage was found in several fields. When feeding damage is found in a field, it is counted and combined with any European corn borer damage found. If the total injury exceeds 15% in corn at pre-tassel or beyond, a spray is recommended. Once the corn has reached the silking stage, sprays may be based on captures of moths in pheromone traps. This prevents larvae from getting into the silk channel and damaging ears without leaving visible injury for field scouting. If three or more moths are caught in a week in silking fields, a spray is recommended, unless the field is currently under a spray interval for corn earworm. Sprays for corn earworm should provide control of fall armyworm.

Male Fall Armyworm Moth

Male Fall Armyworm Moth, photo by David Handley

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:  Flies have been in several Maine berry fields over the past week. Growers with ripening blueberries or raspberries should be on the alert for flies or larvae in the fruit. For details, visit our Spotted Wing Drosophila blog.

Squash vine borer moths were caught in pheromone traps in Wells, Biddeford, Cape Elizabeth, Nobleboro, Farmington, Oxford and New Gloucester this week. The Biddeford, Cape Elizabeth, New Gloucester and Oxford sites were above the 5 moths per week spray threshold, and a spray was recommended. This pest is active in much of the state. Growers with squash and pumpkins should be on the lookout for vine borer symptoms and protect squash plants if moths or damage are seen.

Highmoor Farm EntranceHOLD THE DATES:

Fruit and Vegetable Growers Field Day at Highmoor Farm: Wednesday July 26, 2017 from 8:30 a.m. to 3:00 p.m. Visit the Highmoor Farm website for more information. Please register by July 17! Call 207.933.2100 for additional registration information.

New England Vegetable & Fruit Conference is scheduled for December 12-14, 2017 in Manchester, NH.  Please visit the website, https://newenglandvfc.org/. Details and registration information coming soon.

Sincerely,

David T. Handley
Vegetable and Small Fruit Specialist

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

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Auburn 0 2 0 6% No spray recommended
Biddeford 0 0 2 23% One spray recommended for ECB
Bowdoinham 1 1 0 11% No spray recommended
Cape Elizabeth I 2 2 0 10% No spray recommended (no silking corn)
Cape Elizabeth II 6 0 2 23% 5-day spray interval recommended on all silking corn
Dayton I 1 0 0 22% One spray recommended for ECB
Dayton II 1 0 0 1% No spray recommended
Farmington 0 1 0 3% No spray recommended
Lewiston 0 0 6 0% One spray recommended for FAW on all silking corn
New Gloucester 0 0 0 3% No spray recommended
Nobleboro 5 2 6 27% 5-day spray interval recommended on all silking corn
North Berwick 3 0 0 5% 6-day spray interval recommended on all silking corn
Oxford 1 0 2 1% No spray recommended
Poland Spring 1 0 0 52% One spray recommended for ECB +FAW
Sabattus 1 0 0 32% One spray recommended for ECB
Wales 3 0 0 0% 6-day spray interval recommended on all silking corn
Wayne 1 0 0 10% No spray recommended
Wells I 0 0 0 21% One spray recommended for ECB on pre-tassel corn
Wells II 1 1 0 0% No spray recommended

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

IPM Web Pages:

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

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

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

 

 

Strawberry IPM Newsletter No. 6 – July 11, 2017

Tuesday, July 11th, 2017

StrawberriesStrawberry IPM Newsletter No. 6 – July 11, 2017
Click on photos to enlarge.

RENOVATION AND WEED MANAGEMENT ISSUE

Get Your Strawberry Beds Ready for Next Year

Manage Pests in Day-Neutral Strawberries

Not a bad winter, by Maine standards, but some fields did show a small amount of winter injury this spring. The extremely dry summer also took its toll as many beds had thinner plant populations than normal this spring, due to a lack of good runner growth last summer. An extended cool spring delayed early plant and flower development, leading to a later ripening crop. Many PYO fields opened five to fifteen days later than normal this year. Pest pressure was relatively light in most fields. Spider mites were the most common problem across the state, although some fields had more serious problems with strawberry bud weevil or “clipper”. Disease pressure was also light in most fields, with leaf spot being the most common problem. Because of the rain, many fields needed at least one extra fungicide treatment to keep gray mold to a minimum. All in all, the harvest was pretty good, with quantity and quality very good, and berry size down a bit, likely due to last year’s drought during flower bud formation.

Now that harvest is coming to an end, don’t forget about your strawberry plants. Renovation of your beds should begin soon after harvest to allow as much time as possible for the plants to re-establish and form lots of healthy flower buds for next year. Follow the recommended renovation steps listed below for matted row strawberries. 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. Foliar diseases are more likely to become apparent under wet weather conditions. The most common summer diseases are powdery mildew, leaf spot and leaf scorch. Fungicides available for these diseases include captan, Topsin-M®, Cabrio®, and Pristine®. See the New England Small Fruit Management Guide for detailed descriptions of these diseases and their management.

Powdery Mildew

Powdery Mildew, photo by David Handley

Leaf Scorch

Leaf Scorch, photo by David Handley

Black root rot is a disease complex which can be brought on by a combination of factors, 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.

Black Vine Weevil

Black Vine Weevil, photo by David Handley

Strawberry Root Weevil Grub

Strawberry Root Weevil Grub, photo by David Handley

White grubs have been a problem in some fields in recent years. 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 that 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. Sevin® is registered for control of root worm after harvest.

Strawberry Rootworm Beetle

Strawberry Rootworm Beetle, photo by James Dill

Potato Leafhopper

Potato Leafhopper, photo by James Dill

Keep a lookout for potato leafhoppers; the injury has been very common in new strawberry beds this year. 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 Assail®, malathion, carbaryl or Provado®.

MITES
Two-spotted spider mites can increase significantly during the summer, especially in hot, dry weather. Continue to take leaf samples for spider mites throughout the summer. 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.

Two-spotted Spider Mites

Two-spotted Spider Mites, photo by David Handley

Cyclamen Mite Damage

Cyclamen Mite Damage, photo by David Handley

Cyclamen mites:  If your field had cyclamen mite symptoms this spring, summer is a good time to control them. After mowing off the leaves, access to the crowns where the mites reside is greatly improved. Plants showing weak growth and yellow, crinkled leaves may be infested with cyclamen mite. These 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. The miticide Portal® can be effective, but must be applied with lots of water (200 gals.) to be sure that the material is carried down into the crowns.

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 established strawberry beds:

  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.
  1. 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.
  1. Napropamide (Devrinol®): This pre-emergent herbicide 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.
  1. 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.
  1. Clopyralid (Spur®): Has both pre-emergent and post emergent activity on many weeds. One application per crop per year following harvest to emerged weeds. Apply uniformly in a minimum of 10 gallons of water per acre. Do not tank mix with other herbicides. Offers control of clover, dandelion and thistle.
  1. 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 6 weeks of terbacil (Sinbar®) applications, to avoid leaf injury. Sethoxydim should be used in combination with a crop oil concentrate. Do not tank mix with 2, 4-D. A second application is often needed for control of perennial grasses.
  1. Clethodim (Arrow®, Prism®, Select®): A post-emergent herbicide, similar in activity to Poastâ, 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.
  1. 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.
  1. 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 only between rows, with a sprayer shielded to protect the strawberries. This product no residual soil activity. It has a strong, unpleasant odor.
  1. 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®).
  1. 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.
  1. 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, mite 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 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®), or clopyralid (Spur®).
  1. 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.
  2. Tilling Sides of Strawberry Rows

    Tilling Sides of Strawberry Rows, photo by David Handley

    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.

  3. 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.
  1. 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.
  2. Strawberry Irrigation

    Strawberry Irrigation, photo by David Handley

    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.

  1. 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 the Analytical Lab and Maine Soil Testing Service, 5722 Deering Hall, Room 407, University of Maine, Orono, ME 04469-5722, telephone: 207.581.2945.

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.

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 (Drosophila suzukii) is a new pest, which is a concern for day-neutral strawberries, fall raspberries and blueberries. This is a small fruit fly, similar to those that hover around the 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. Infested fruit quickly rots and has no shelf life. This insect 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. Frequently repeated insecticide sprays (1 to 2 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, and have found that they are already active this season. However, these traps may not provide adequate early warning, i.e. when we find them in a trap they are probably already established in the field. Products that provide good control of drosophila on strawberries include Radiant®, Brigade®, Danitol®, malathion and Assail®. Keeping fields clean of over-ripe and rotten fruit will also help reduce the incidence of this insect. For more information on identifying spotted wing drosophila and updates on populations around the state, visit our Spotted Wing Drosophila blog.

Tarnished plant bug:  This is one of the most prevalent and persistent pests of day-neutral strawberries, because 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

Tarnished Plant Bug, photo by Charles Armstrong

Tarnished Plant Bug
Product Days to Harvest
Brigade® 0
Pyganic® 0
Assail® 1
Dibrom® 1
Rimon® 1
malathion 3

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

Two-spotted Spider Mites, photo by David Handley

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 2017-2018 New England Small Fruit Management Guide online for more detailed pest information.

Hold the Dates:

Fruit and Vegetable Growers Field Day at Highmoor Farm: Wednesday July 26, 2017 from 8:30 a.m. to 3:00 p.m. Visit the Highmoor Farm website for more information. Please register by July 17! Call 933.2100 for additional registration information.

New England Vegetable & Fruit Conference is scheduled for December 12-14, 2017 in Manchester, NH.  Please visit the website, https://newenglandvfc.org/. Details and registration information coming soon.

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.

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

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

Friday, July 7th, 2017

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

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

CORN EARWORM ACTIVE IN SILKING CORN FIELDS

European Corn Borer Feeding Increasing in Pre-Tassel Fields

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

European Corn Borer Damage on Pre-tassel Stage corn

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

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

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

drosophila trap

Drosophila Trap, photo by David Handley

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

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

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

Two Squash Vine Borer Moths

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

Squash Vine Borer Larva

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

Sincerely,

David T. Handley
Vegetable and Small Fruit Specialist

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

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Biddeford 1 0 0 20% No spray recommended (corn not yet pre-tassel)
Bowdoinham 0 1 0 22% One spray recommended for ECB
Cape Elizabeth I 0 0 0 1% No spray recommended
Cape Elizabeth II 5 6 0 20% 5-day spray interval recommended on all silking corn
Dayton I 1 0 0 2% No spray recommended
Dayton II 3 0 0 9% 6-day spray interval recommended on all silking corn
Farmington 0 0 0 7% No spray recommended
Lewiston 4 0 0 2% 5-day spray interval recommended on all silking corn
Nobleboro 1 0 0 7% No spray recommended
Oxford 0 1 0 1%
Poland Spring 0 0 0 21% No spray recommended (corn not yet pre-tassel)
Sabattus 0 0 0 26% One spray recommended for ECB
Wayne 0 0 0 19% One spray recommended for ECB on pre-tassel corn
Wells I 0 0 0 19% One spray recommended for ECB on pre-tassel corn
Wells II 3 0 0 6-day spray interval recommended on all silking corn

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

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

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

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