Posts Tagged ‘sweet corn’

Sweet Corn IPM Newsletter No. 13 – September 15, 2017

Friday, September 15th, 2017

Sweet CornSweet Corn IPM Newsletter No. 13 – September 15, 2017
Click on photos to enlarge.

Last Issue for 2017!

INCREASING PEST PRESSURE TO END SEASON

Fresh Silking Corn Remaining Likely to Need Protection

This will be the final issue of the Sweet Corn IPM Newsletter for the 2017 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, Tammy Cushman, Lindsey Ridlon and Sean McAuley. Have questions, comments or suggestions about the program? Please call or e-mail us.

SITUATION
It appears the tropical fronts and warmer weather pushing through Maine have only brought about a moderate increase in moth activity. There may be more activity associated with tropical storms in the coming weeks, however, so the threat to any fresh silking corn that still remains may increase.

European corn borer:  No moth captures for a second week, so no real threat from European corn borer to end the season. There was no fresh larval feeding injury on younger corn and no sprays for this insect were recommended.

Corn Earworm Moth

Corn Earworm Moth, photo by David Handley

Fall Armyworm Moths

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

Corn earworm:  Moth counts rose moderately in most locations this week, keeping most fields with any fresh silk remaining on a spray schedule. A 6-day spray interval was recommended for silking corn in Oxford and one Wells site this week. A 5-day spray schedule was recommended in Auburn, one Dayton site and Sabattus. A 4-day spray interval was recommended in Cape Elizabeth, one Dayton location, North Berwick, and one Wells site.

Fall armyworm:  Moth activity was spotty around the state this week, with some sites seeing a slight increase in activity and others not. No sprays were recommended exclusively for fall armyworm on silking corn, because all sites over the 3-moth threshold were on a spray interval for corn earworm, including Cape Elizabeth, Dayton, Oxford and Sabattus. No sites were over the 15% injury threshold for larval feeding damage.

Just a reminder that fall is a great time for soil testing
Late summer and early fall are good times to seed cover crops to prevent soil erosion and to retain soil nutrients. It is also a great time to check on the health of your soil. Getting your soil test results before the ground freezes allows time to correct soil pH with additions of lime, and incorporate any needed supplements into the soil, such as phosphorus, potassium, magnesium or other nutrients to correct deficiencies, and/or manure to increase organic matter. Fall applications of lime and some nutrients (not nitrogen, as it is prone to leaching) are often better, because the fields are drier than in the spring. It’s easier to move equipment around, and the nutrients will have time to be worked into the soil before the plants need them. You can pick up soil test boxes and forms at any county office of the University of Maine Cooperative Extension, or call us here at Highmoor Farm if you’d like us to send you some. For details on soil testing at the University of Maine Analytical Laboratory and Soil Testing Service, you can visit their website at: https://umaine.edu/soiltestinglab/.

The New England Vegetable and Fruit Conference will be held in Manchester, New Hampshire on December 12, 13 and 14, 2017. Program and registration information will be coming soon. Visit the website, http://www.newenglandvfc.org/.

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 5-day spray interval recommended on all silking corn
Bowdoinham 1 0 0 0% No spray recommended
Cape Elizabeth I 26 0 17 4-day spray interval recommended on all silking corn
Cape Elizabeth II 16 0 13 0% 4-day spray interval recommended on all silking corn
Dayton I 63 0 13 0% 4-day spray interval recommended on all silking corn
Dayton II 6 0 4 5-day spray interval recommended on all silking corn
Monmouth 1 0 1 0% No spray recommended
North Berwick 11 0 2 4-day spray interval recommended on all silking corn
Oxford 3 0 9 6-day spray interval recommended on all silking corn
Sabattus 5 0 4 5-day spray interval recommended on all silking corn
Wales 1 0 1 0% No spray recommended
Wayne 0 0 0 No spray recommended
Wells I 2 0 2 6-day spray interval recommended on all silking corn
Wells II 10 0 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. 12 – September 11, 2017

Monday, September 11th, 2017

Sweet CornSweet Corn IPM Newsletter No. 12 – September 11, 2017
Click on photos to enlarge.

CORN PEST THREAT MODERATE BUT VARIABLE

Corn Earworm and Fall Armyworm Active in Silking Corn at Most Sites

SITUATION
Cool nights and some rainy days appear to be holding corn pests at moderate levels for this time of year, as the sweet corn season winds down. However, we may still have the remnants of tropical storms to deal with over the next couple of weeks which could cause an increase in corn earworm and/or fall armyworm populations. Next week will be the last scheduled issue of the Sweet Corn IPM Newsletter for the 2017 season.

European corn borer:  No moth captures this week, suggesting the threat of corn borer may be over for this season. Larval feeding injury on younger corn was also very low, and did not exceed threshold at any location.

Corn earworm:  Overall, moth counts remain fairly low this week, but high enough to keep some sites on a tight spray schedule for any fresh silking corn remaining. A 5-day spray schedule was recommended in Auburn, New Gloucester, North Berwick, and Wells.  A 4-day spray interval was recommended in Biddeford, Cape Elizabeth, one Dayton location, Lewiston, Monmouth and Sabattus.

Corn Earworm Feeding on Corn

Corn Earworm Feeding on Corn, photo by David Handley

Fall Army Worm on Pre-tassel Corn Plant

Fall Army Worm on Pre-tassel Corn, photo by David Handley

Fall armyworm:  Moth activity is becoming spottier from site to site, with some locations well over the 3-moth threshold for silking corn, and others seeing few, if any moths. A spray for fall armyworm on silking corn was recommended in one Dayton site, Nobleboro, Poland Spring and Wales. Other sites, including Auburn, Biddeford, Cape Elizabeth, Dayton, Lewiston, Monmouth, North Berwick, and Sabattus were also over the 3-moth threshold, but are on a spray schedule for corn earworm. No sites were over the 15% injury threshold for larval feeding damage in pre-tassel to tassel corn.

Annual end of corn season checklist:

  1. Plow down corn stalks and stubble to destroy overwintering larvae of European corn borer.
  2. Plant a cover crop, such as winter rye, to prevent soil erosion and to add organic matter to the soil.
  3. Take a soil test to determine if lime or other nutrients should be applied.
  4. Plan to rotate your crops to prevent pests from building up in any one location.
  5. Evaluate your weed management results. What worked well and what didn’t?  Which weeds were the biggest problems?  How can you improve control?

Unplowed Corn Field

Unplowed Corn Field, photo by David Handley

Oats Cover Crop

Oats Cover Crop, photo by David Handley

The New England Vegetable & Fruit Conference will be held in Manchester, NH on December 12, 13, and 14, 2017. Program and registration information will be coming soon. Visit the website: http://www.newenglandvfc.org/.

Reminder: 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 5 0 10 5-day spray interval recommended on all silking corn
Biddeford 8 0 7 4-day spray interval recommended on all silking corn
Bowdoinham 0 0 0 No spray recommended
Cape Elizabeth I 25 0 38 4-day spray interval recommended on all silking corn
Cape Elizabeth II 8 0 17 4-day spray interval recommended on all silking corn
Dayton I 41 0 107 0% 4-day spray interval recommended on all silking corn
Dayton II 0 0 5 One spray for FAW on all silking corn
Lewiston 15 0 4 4-day spray interval recommended on all silking corn
Monmouth 12 0 9 4-day spray interval recommended on all silking corn
New Gloucester 6 0 0 5-day spray interval recommended on all silking corn
Nobleboro 0 0 42 One spray for FAW on all silking corn
North Berwick 4 0 3 3% 5-day spray interval recommended on all silking corn
Oxford 1 0 2 No spray recommended
Poland Spring 0 0 12 One spray for FAW on all silking corn
Sabattus 14 0 7 4-day spray interval recommended on all silking corn
Wales 0 0 5 One spray for FAW on all silking corn
Wayne 0 0 0 No spray recommended
Wells I 5 0 2 5-day spray interval recommended on all silking corn
Wells II 4 0 2 9% 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. 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.