Posts Tagged ‘sweet corn’

Sweet Corn IPM Newsletter No. 9 – August 22, 2014

Friday, August 22nd, 2014

Sweet CornSweet Corn IPM Newsletter No. 9 – August 22, 2014

Click on photos to enlarge.

CORN EARWORM NUMBERS INCREASING

Highest Threat in Southern Coastal Region

SITUATION
Cooler days and nights have slowed later corn development, but supply and quality still seems to be good. There has been a significant increase in pest activity, but for the moment it is fairly localized in the southern coastal region.

European corn borer: We continue to catch moths in most locations. Although, with the exception of our Sabattus site, the counts are fairly low. It appears that a second generation of corn borer is underway, which could threaten silking corn in fields that are not on a spray schedule for corn earworm. Biddeford, North Berwick, Sabattus, and Warren were over the threshold of 5 moths per week in silking corn. Only the North Berwick site was not also on a spray regime for corn earworm, so a spray was recommended there. European corn borer feeding damage in pre-tassel corn was over the 15% threshold in North Berwick, Biddeford, Cape Elizabeth, Poland Spring and Wayne this week.

Corn earworm: Corn earworm moth counts jumped higher in some sites this week, most notably in the southern coastal region. A 4-day spray interval was recommended for corn earworm on silking fields in Biddeford, Cape Elizabeth, Garland, Wales and one Wells site. A 5-day spray interval was recommended in Monmouth and one Dayton site. A 6-day spray interval was recommended in Farmington, Levant, one Lewiston site, Sabattus, Warren and Wayne.

Corn Earworm Feeding on Corn

Corn Earworm Feeding on Corn, photo by David Handley

Fall Armyworm Injury on Corn Leaves

Fall Armyworm Injury on Corn Leaves, photo by David Handley

Fall armyworm: Most trapping sites had few, if any moths this week, although feeding damage from larvae has increased in some fields. Fields in Biddeford, Cape Elizabeth, Farmington, Monmouth, Nobleboro, and one Wells site exceeded the threshold of 3 moths per week in silking corn. However, only the Nobleboro site was not on a spray regime for corn earworm. Fall armyworm feeding damage on plants exceeded the 15% damage threshold alone, or in combination with European corn borer feeding, in Biddeford, Dayton and Warren this week.

Aphids on corn

Aphids on Corn, photo by Kaytlin Woodman

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

Pesticide disposal: This October, the Maine Board of Pesticides Control (BPC) and the Maine Department of Environmental Protection will offer free disposal of banned or unusable pesticides. Collection will occur at sites located in Presque Isle, Bangor, Augusta and Portland. To qualify, people must register by September 26, 2014. Registration is mandatory; drop-ins will not be permitted. To register or get details and important information about the temporary storage and transportation of obsolete pesticides, go to the BPC web site at http://www.thinkfirstspraylast.org and click on Obsolete Pesticide Collection, or call 207-287-2731.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Biddeford 35 5 3 36% 4-day spray interval recommended on all silking corn
Cape Elizabeth I 72 4 0 4-day spray interval recommended on all silking corn
Cape Elizabeth II 67 4 9 29% 4-day spray interval recommended on all silking corn
Charleston 0 1 0 No spray recommended
Dayton I 0 0 0 No spray recommended
Dayton II 4 3 0 29% 5-day spray interval recommended on all silking corn
Farmington 2 1 4 6-day spray interval recommended on all silking corn
Garland 9 0 0 1% 4-day spray interval recommended on all silking corn
Levant 2 0 0 2% 6-day spray interval recommended on all silking corn
Lewiston I 2 3 0 6-day spray interval recommended on all silking corn
Lewiston II 0 4 0 7% No spray recommended
Monmouth 5 3 10 0% 5-day spray interval recommended on all silking corn
Nobleboro 0 2 4 One spray recommended for FAW on silking corn
No. Berwick 0 6 1 25% One spray recommended for ECB on silking corn
Oxford 0 2 0 3% No spray recommended
Palmyra 0 0 0 No spray recommended
Poland Spring 0 0 0 6% No spray recommended
Sabattus 3 29 0 6-day spray interval recommended on all silking corn
Wales 11 1 1 4-day spray interval recommended on all silking corn
Warren 2 10 2 37% 6-day spray interval recommended on all silking corn
Wayne 3 1 0 27% 6-day spray interval recommended on all silking corn
Wells I 1 0 1 0% No spray recommended
Wells II 15 3 4 11% 4-day spray interval recommended on all silking corn

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

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

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

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

Sweet Corn IPM Newsletter No. 8 – August 15, 2014

Monday, August 18th, 2014

Sweet CornSweet Corn IPM Newsletter No. 8 – August 15, 2014

Click on photos to enlarge.

PEST NUMBERS INCREASE IN MOST FIELDS

Fall Armyworm, European Corn Borer Moth Counts Rising

SITUATION
The recent storm has caused lodging in some fields, but corn plants can often come back up if the roots have not been badly damaged. However, spraying and harvesting lodged corn can be difficult. The stream of weather coming up from the south will likely cause pest numbers to increase in the near future, although for this week we have only seen relatively moderate increases in fall armyworm and European corn borer moth captures. The latter may indicate that a second generation is now getting underway.

European corn borer: Moth counts were generally higher in most locations this week, although a few sites still had no moths in the traps. This increase in trap captures suggests that a second generation of corn borer may be underway and could threaten silking corn in fields that are not on a spray schedule for corn earworm. Sabattus, Farmington, Livermore Falls, Nobleboro, Oxford and Palmyra were over the threshold of 5 moths per week in silking corn. The Farmington and Palmyra sites were also on spray regimes for corn earworm, so no additional sprays should be needed there. European corn borer feeding damage in pre-tassel corn was over the 15% threshold in Biddeford, Cape Elizabeth, Dayton, Poland Spring and Warren 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 Larvae

Corn Earworm Larvae, photo by David Handley

Corn earworm: Corn earworm moth counts are rising in some locations, as we expect late in the season when more weather comes up from the south carrying moths with it. A 6-day spray interval was recommended for corn earworm on silking fields in Biddeford, one Dayton site, Farmington, Palmyra, Warren, and one Wells site. A 5-day spray interval was recommended for one Cape Elizabeth site, Charleston, one Dayton site, New Gloucester, and North Berwick. A 4-day spray interval was recommended at one Lewiston site.

Fall armyworm: Moth counts continue to be erratic around the state, but were significantly higher in some sites this week (nearly 100 moths in a Cape Elizabeth trap). Fields in Biddeford, Cape Elizabeth, Monmouth, Nobleboro, Wales, Warren and one Wells site exceeded the threshold of 3 moths per week in silking corn. However, only the Monmouth, Nobleboro and Wales sites were not on a spray regime for corn earworm. Fall armyworm feeding damage on plants was only noted in Cape Elizabeth this week, where it exceeded the 15% damage threshold.

Squash vine borer moths were caught in pheromone traps in Biddeford and Cape Elizabeth this week, but did not exceed the threshold of five moths per week. You can download a free copy of the University of New Hampshire’s new fact sheet, Managing Squash Vine Borer Problems in New Hampshire from their website.

Two Squash Vine Borer Moths

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

Sap beetle on strawberry

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

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

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Biddeford 2 0 5 22% 6-day spray interval recommended on all silking corn
Cape Elizabeth I 1 0 2 13% No spray recommended
Cape Elizabeth II 6 2 97 50% 5-day spray interval recommended on all silking corn
Charleston 5 4 0 5-day spray interval recommended on all silking corn
Dayton I 3 0 0 6-day spray interval recommended on all silking corn
Dayton II 6 0 1 38% 5-day spray interval recommended on all silking corn
Farmington 2 10 1 6-day spray interval recommended on all silking corn
Levant 1 3 0 3% No spray recommended
Lewiston I 9 3 0 0% 4-day spray interval recommended on all silking corn
Lewiston II 0 0 0 3% No spray recommended
Livermore Falls 1 5 1 0% One spray recommended for ECB on silking corn
Monmouth 0 4 18 One spray recommended for FAW on silking corn
New Gloucester 6 1 0 8% 5-day spray interval recommended on all silking corn
Nobleboro 1 35 8 One spray recommended for ECB+FAW on silking corn
No. Berwick 7 0 0 7% 5-day spray interval recommended on all silking corn
Oxford 1 7 2 2% One spray recommended for ECB on silking corn
Palmyra 2 6 0 6-day spray interval recommended on all silking corn
Sabattus 0 81 0 One spray recommended for ECB on silking corn
Wales 1 0 6 6% One spray recommended for FAW on silking corn
Warren 2 3 27 35% 6-day spray interval recommended on all silking corn
Wells I 0 0 0 4% No spray recommended
Wells II 2 1 3 4% 6-day spray interval recommended on all silking corn

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

IPM Web Pages:

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

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

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

Sweet Corn IPM Newsletter No. 6 – July 31, 2014

Thursday, July 31st, 2014

Sweet CornSweet Corn IPM Newsletter No. 6 – July 31, 2014

Click on photos to enlarge.

PEST PRESSURE MODERATE AS CORN HARVEST BEGINS

Corn Earworm and Fall Armyworm Counts Low, but Still Threaten Silking Corn

SITUATION
Corn harvest is getting into full swing in southern Maine. High winds associated with the numerous thunderstorms have caused minor lodging in some fields. Excessive rainfall may also result in poor herbicide performance and leaching of fertilizer, especially nitrogen. Pest numbers remain relatively moderate, although silking corn in most locations requires protection against corn earworm and/or fall armyworm.

Wind Blown Corn Field

Wind Blown Corn Field, photo by David Handley

European corn borer: Moth counts continue to decline this week, suggesting that the first generation of this insect may be coming to an end. Most sites had no moths in the traps. Only the Sabattus site was over the threshold of 5 moths per week in silking corn. European corn borer feeding damage was only over the 15% threshold in Wales.

Corn earworm: Corn earworm remains widely distributed but moth counts are still moderate. A 6-day spray interval was recommended for corn earworm on silking fields in Dayton, Garland, Gray, Monmouth, Wales, New Gloucester, Nobleboro, North Berwick, Oxford and Palmyra. A 5-day spray interval was recommended for Biddeford, one Cape Elizabeth site, Charleston, Levant, Lewiston, Sabattus, Warren and one Wells location.

Fall armyworm: Moth counts are variable around the state this week. Fields in Biddeford, Cape Elizabeth, Dayton, Garland, Levant, Lewiston, Monmouth and Warren exceeded the threshold of 3 moths per week in silking corn. However, only the Garland site and one Lewiston site were not on a spray regime for corn earworm. Feeding damage on plants was only noted in New Gloucester this week, but did not exceed the 15% damage threshold.

Adult Fall Armyworm

Adult Fall Armyworm, photo by David Handley

Squash Vine Borer Larva

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

Squash vine borer moths were caught in pheromone traps in Biddeford, Dayton, New Gloucester and Wells this week. The threshold of five moths per week was exceeded at the Biddeford, Dayton and New Gloucester sites. Vine borers threaten summer squash, winter squash and pumpkins. See the New England Vegetable Management Guide for control options.

Rust on Corn

Rust on Corn, photo by David Handley

Corn Rust: Rust is a fungus disease that causes reddish-brown pustules to form on the leaves, stalks and husks, reducing the visual quality of the ears. Severe infections can reduce ear size, especially if they occur prior to tasseling. Typically, corn rust does not become a problem until late in the season, because it can’t overwinter in Maine and must move in from the south. A fungicide spray for rust would only be recommended if the infection were noticed in a field prior to tasseling. Later infections are unlikely to cause enough damage to the crop to justify control measures. Materials available to control corn rust include Bravo®, Quilt® and maneb/mancozeb.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Biddeford 4 4 11 6% 5-day spray interval recommended on all silking corn
Bowdoinham 0 0 0 0% No spray recommended
Cape Elizabeth I 7 2 3 0% 5-day spray interval recommended on all silking corn
Cape Elizabeth II 0 1 43 One spray recommended for FAW on silking corn
Charleston 6 0 0 5-day spray interval recommended on all silking corn
Dayton 3 0 5 6-day spray interval recommended on all silking corn
Farmington 0 0 0 0% No spray recommended
Garland 2 0 5 2% 6-day spray interval recommended on all silking corn
Gray 3 0 0 13% 6-day spray interval recommended on all silking corn
Levant 4 0 5 3% 5-day spray interval recommended on all silking corn
Lewiston I 7 0 4 3% 5-day spray interval recommended on all silking corn
Lewiston II 0 0 4 One spray recommended for FAW on silking corn
Livermore Falls 0 0 0 1% No spray recommended
Monmouth 2 1 12 9% 6-day spray interval recommended on all silking corn
New Gloucester 2 0 0 3% 6-day spray interval recommended on all silking corn
Nobleboro 2 0 6-day spray interval recommended on all silking corn
No. Berwick 3 0 0 6-day spray interval recommended on all silking corn
Oxford 2 0 1 8% 6-day spray interval recommended on all silking corn
Palmyra 2 2 0 5% 6-day spray interval recommended on all silking corn
Sabattus  0  12  1  1% One spray recommended for ECB on silking corn
Wales  3  0  1  20%  6-day spray interval recommended on all silking corn
Warren 5 0 8 1% 5-day spray interval recommended on all silking corn
Wells I 1 0 0 0% No spray recommended
Wells II 5 0 2 5-day spray interval recommended on all silking corn

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

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

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

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

 

Sweet Corn IPM Newsletter No. 5 – July 28, 2014

Tuesday, July 29th, 2014

Sweet CornSweet Corn IPM Newsletter No. 5 – July 28, 2014

Click on photos to enlarge.

EARLY CORN HARVEST UNDERWAY

Pest Pressure Remains Moderate for Most Locations

SITUATION
Hot weather and adequate moisture have provided good growing conditions for corn. Early harvest is underway in southern Maine and many fields are now silking, meaning they are now more susceptible to all of the major corn pests. However, in spite of a recent spate of storm fronts from the west, pest numbers have remained relatively moderate in most locations.

European corn borer: With the exception of two northern sites, moth counts were very low this week. Most sites had no moths in the traps. However, silking fields in Levant and Palmyra were over the threshold of 5 moths per week in silking corn. The Levant site was also on a spray regime for corn earworm, so no additional spray was recommended. European corn borer feeding damage was over threshold in pre-tassel to tasseling fields only at our Biddeford site this week.

Corn earworm: While corn earworm was widely distributed throughout our sites this week, moth counts were moderate. However, many later planted fields are now coming into silk and will need to be protected. A 6-day spray interval was recommended for corn earworm on silking fields in North Berwick, Wells, Biddeford, Cape Elizabeth, Bowdoinham, Gray, Farmington, one Lewiston site and Charleston. A 5-day spray interval was recommended for one Dayton site and one Lewiston site, Sabattus, Warren, Nobleboro and Levant.

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 were higher in a few locations this week. Fields in Cape Elizabeth, Garland, Lewiston, Monmouth and Nobleboro exceeded the threshold of 3 moths per week in silking corn. However, only the Garland site was not also on a spray regime for corn earworm. Feeding damage on plants was noted this week in fields in Biddeford, Cape Elizabeth and Sabattus. Although not yet over threshold on it’s own, when combined with European corn borer damage the total feeding exceeded the 15% threshold in Biddeford.

Squash vine borer moths were caught in pheromone traps in Biddeford, Oxford and Wells this week. The threshold of five moths per week was exceeded only at the Wells site. Vine borers threaten summer squash, winter squash and pumpkins. See the 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

Potato Leafhopper

Potato Leafhopper, photo by James Dill

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

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Biddeford 2 0 2 17% 6-day spray interval recommended on all silking corn
Bowdoinham 3 0 1 4% 6-day spray interval recommended on all silking corn
Cape Elizabeth I 3 0 3 6% 6-day spray interval recommended on all silking corn
Cape Elizabeth II 3 0 12 2% 6-day spray interval recommended on all silking corn
Charleston 2 0 0 6-day spray interval recommended on all silking corn
Dayton I 0 0 0 No spray recommended
Dayton II 6 0 0 12% 5-day spray interval recommended on all silking corn
Farmington 2 0 2 1% 6-day spray interval recommended on all silking corn
Garland 1 0 5 0% One spray recommended for FAW on silking corn
Gray 3 0 0 6-day spray interval recommended on all silking corn
Levant 4 6 0 2% 5-day spray interval recommended on all silking corn
Lewiston I 5 0 10 5% 5-day spray interval recommended on all silking corn
Lewiston II 3 0 2 6-day spray interval recommended on all silking corn
Livermore Falls 0 0 0 0% No spray recommended
Monmouth 1 2 11 No spray recommended (no silking corn)
Nobleboro 5 0 3 1% 5-day spray interval recommended on all silking corn
No. Berwick 2 0 0 6-day spray interval recommended on all silking corn
Oxford 1 0 1 2% No spray recommended
Palmyra 1 19 1 3% One spray recommended for ECB on silking corn
Sabattus 5 2 0 13% 5-day spray interval recommended on all silking corn
Wales 1 0 2 0% No spray recommended
Warren 7 0 2 0% 5-day spray interval recommended on all silking corn
Wells I 3 0 0 3% 6-day spray interval recommended on all silking corn
Wells II 1 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:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/

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

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

Sweet Corn IPM Newsletter No. 4 – July 18, 2014

Friday, July 18th, 2014

Sweet CornSweet Corn IPM Newsletter No. 4 – July 18, 2014

Click on photos to enlarge.

CORN EARWORM COUNTS CLIMBING

Pest Pressure Now Moderate for Most Locations

SITUATION
Despite a series of storms coming up from the south, corn pest pressure has remained moderate in most locations this week. Harvest of early corn planted under plastic will likely start next week in southern Maine.

European corn borer:  Moth counts were erratic again this week, with some locations having the highest numbers of the season, while others had none. Silking fields in Dayton, Lewiston, Livermore Falls, Nobleboro and Sabattus were over the threshold of 5 moths per week in silking corn. The Lewiston, Nobleboro and Sabattus sites were also on a spray regime for corn earworm, so no additional spray was recommended. European corn borer feeding damage was over threshold in pre-tassel to tasseling fields in Biddeford, Nobleboro, North Berwick and Sabattus this week.

European Corn Borer Damage on Pre-tassel Stage corn

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

Corn Earworm Moth

Corn Earworm Moth, photo by David Handley

Corn earworm:  Most locations have now caught at least one corn earworm moth, and counts have risen in a few locations this week. But moth numbers are still relatively low in many fields, given the recent storms moving in from the south. A 6-day spray interval was recommended for corn earworm on silking fields in one Cape Elizabeth location, one Dayton location, Gray, New Gloucester, Nobleboro, North Berwick, Sabattus and one Wells location. A 5-day spray interval was recommended for one Cape Elizabeth site and one Lewiston site. A 4-day spray interval for silking corn was recommended for Wales and Warren.

Fall armyworm:  Moth counts were mostly very low this week. Only one site in Cape Elizabeth exceeded the threshold of 3 moths per week in silking corn. However, this field was also on a spray regime for corn earworm, so no additional sprays should be needed. Feeding damage on plants was noted this week in fields in Biddeford, North Berwick and one Wells site. Although not yet over threshold on it’s own, when combined with European corn borer damage the total feeding exceeded the 15% threshold.

Fall Armyworm Eggs on Corn

Fall Armyworm Eggs on Corn, photo by David Handley

Japanese Beetle

Japanese Beetle, photo by Edwin Remsberg, USDA

Japanese Beetles are becoming plentiful in southern and mid-state areas. These insects often find their way into cornfields and may feed on the silks of developing ears, causing poor tip fill. Sprays for corn earworm (except Bt’s) will often control the Japanese beetle as well.

Squash vine borer moths were caught in pheromone traps in Biddeford, Cape Elizabeth, Dayton, New Gloucester and Wells this week. This week’s counts were some of the highest we’ve seen. The threshold of five moths per week was exceeded in Dayton, New Gloucester and Biddeford.  Vine borers threaten summer squash, winter squash and pumpkins. See the 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

Late Blight on Potato Leaf

Late Blight on Potato Leaf, photo by James Dill

Late Blight Update:  Infections have been confirmed from potatoes in commercial fields and home gardens in southern Maine. With hot, humid weather, this disease can spread rapidly through a region. Growers should scout their potato and tomato fields for symptoms and apply preventative fungicides. For more information visit our Cooperative Extension Publications website and the 2014-2015 New England Vegetable Management Guide.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

 

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Biddeford 0 1 1 18% One spray recommended for ECB + FAW feeding
Cape Elizabeth I 2 3 0 5% 6-day spray interval recommended on all silking corn
Cape Elizabeth II 4 0 10 5-day spray interval recommended on all silking corn
Charleston 0 0 1 No spray recommended
Dayton I 0 7 0 One spray recommended for ECB on silking corn
Dayton II 2 0 1 11% 6-day spray interval recommended on all silking corn
Farmington 1 2 1 2% No spray recommended
Garland 1 0 0 0% No spray recommended
Gray 2 1 0 6-day spray interval recommended on all silking corn
Levant 0 2 0 0% No spray recommended
Lewiston I 6 5 0 5-day spray interval recommended on all silking corn
Lewiston II 1 3 0 0% No spray recommended
Livermore Falls 1 12 0 2% One spray recommended for ECB on silking corn
Monmouth 1 0 0 No spray recommended
New Gloucester 2 0 1 1% 6-day spray interval recommended on all silking corn
Nobleboro 3 5 0 29% 6-day spray interval recommended on all silking corn
No. Berwick 2 0 0 41% 6-day spray interval recommended on all silking corn
Oxford 0 4 0 1% No spray recommended
Palmyra 0 2 0 0% No spray recommended
Sabattus 3 8 0 23% 6-day spray interval recommended on all silking corn
Wales 8 1 0 0% 4-day spray interval recommended on all silking corn
Warren 9 0 1 4-day spray interval recommended on all silking corn
Wells I 0 2 0 8% No spray recommended
Wells II 2 2 1 2% 6-day spray interval recommended on all silking corn

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

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

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

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

Sweet Corn IPM Newsletter No. 3 – July 10, 2014

Thursday, July 10th, 2014

Sweet Corn

Sweet Corn IPM Newsletter No. 3 – July 10, 2014

Click on photos to enlarge.

FALL ARMYWORM, CORN EARWORM THREATEN SILKING CORN

Late Blight Alert for Potatoes and Tomatoes!

SITUATION
Last weekend’s storm will likely increase insect activity by bringing up moths from the south. Fortunately, the winds were not strong enough to cause widespread lodging in cornfields. More fields are coming into silk as the warm temperatures continue to push growth.  More silking fields are now on a spray regime for corn earworm and/or fall armyworm. The first indication of late blight in Maine was found this week in a potato field in Buxton.

European Corn Borer Larvae on Pre-tassel Stage Corn

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

European corn borer:  Moth catches were higher in some locations this week but continue to be erratic. Silking fields in Cape Elizabeth and Sabattus were over the threshold of 5 moths per week in traps, and a spray for silking corn was recommended. European corn borer feeding damage was over threshold in pre-tassel to tasseling fields in Biddeford, Bowdoinham, Lewiston and Sabattus this week. Remember that sprays applied at pre-tassel tend to be more effective than whorl or tassel stage sprays, because the larvae are usually more exposed.

Corn earworm:  The impact of the tropical storm does not yet seem to be showing up in moth counts. Moths were higher in one Cape Elizabeth location and more sights are now catching their first moths, including our more northern sites, but there has not yet been a large bump in trap captures. A 6-day spray interval was recommended for early silking fields in Dayton, New Gloucester and one Lewiston site. A 4-day spray interval was recommended for one silking field in Cape Elizabeth.

Fall armyworm:  Moth counts were up significantly in some locations while others still have yet to catch their first fall armyworm.  Fields in Cape Elizabeth, New Gloucester and Lewiston were over the threshold of 3 moths per week in silking corn. However, these fields were also on a spray regime for corn earworm, so no additional sprays should be needed. The first feeding damage on plants from fall armyworm was noted this week in fields in Biddeford and Lewiston. Although not yet threatening alone, when combined with European corn borer damage the total feeding exceeded the 15% threshold.

Fall Armyworm Moths

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

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 North Berwick, Biddeford, Dayton and New Gloucester this week. The threshold of five moths per week was exceeded in North Berwick, Wells, Dayton and Biddeford. This pest threatens summer squash, winter squash and pumpkins. Unlike many moths, squash vine borer moths fly during the day. They are black and orange and resemble wasps. The moths lay eggs at the base of squash plants. The larvae bore into the base of the plants, causing vines to wilt and eventually collapse. See the 2014-2015 New England Vegetable Management Guide for control options.

Late Blight on Potato Leaf

Late Blight on Potato Leaf, photo by James Dill

Late Blight Alert! The first symptoms of late blight were found in a potato field in Buxton this week. This devastating disease of tomatoes and potatoes spreads via spores under warm, wet conditions. Growers should take precautions by applying preventative fungicides. See our publications website and the 2014-2015 New England Vegetable Management Guide for management options.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%FeedingDamage Recommendations / Comments
Biddeford 1 3 2 40% One spray recommended for ECB + FAW
Bowdoinham 0 3 0 22% One spray recommended for ECB
Cape Elizabeth I 0 5 0 5% One spray recommended for ECB on silking corn
Cape Elizabeth II 8 3 12 1% 4-day spray interval recommended on all silking corn
Charleston 0 0 0 0% No spray recommended
Dayton I 2 0 0 6-day spray interval recommended on all silking corn
Dayton II 2 0 0 9% 6-day spray interval recommended on all silking corn
Farmington 1 1 1 12% No spray recommended
Garland 1 6 1 0% No spray recommended (no silking corn)
Levant 0 4 1 0% No spray recommended (no silking corn)
Lewiston I 1 1 0 0% No spray recommended
Lewiston II 2 0 3 20% 6-day spray interval recommended on all silking corn
Livermore Falls 1 0 0 3% No spray recommended
New Gloucester 2 4 6 1% 6-day spray interval recommended on all silking corn
No. Berwick 0 0 1 10% No spray recommended
Oxford 0 1 0 5% No spray recommended
Palmyra 0 15 0 1% No spray recommended (no silking corn)
Sabattus 0 29 0 34% One spray recommended for ECB on silking corn
Wales 0 2 0 3% No spray recommended
Warren 0 0 0 13% No spray recommended
Wells I 1 0 0 5% No spray recommended
Wells II 0 0 1 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:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/

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

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

Sweet Corn IPM Newsletter No. 2 – July 3, 2014

Thursday, July 3rd, 2014

Sweet Corn

Sweet Corn IPM Newsletter No. 2 – July 3, 2014

Click on photos to enlarge.

CORN BORER, CORN EARWORM AND FALL ARMYWORM MOTHS ACTIVE

Silking Corn Needs Protection in Early Fields

SITUATION
Cornfields are developing fast with the onset of warm (very warm) temperatures this week. Several early plantings are now in silk while others are coming into tassel. Any showers that arrive this weekend will be welcomed in early fields where conditions are very dry. All of the major corn pests have arrived and are active in cornfields in much of the state. These are especially a threat to early silking fields, which growers often spray lightly, if at all, assuming the major pests are not yet present in damaging numbers.

European corn borer:  Moth catches are spotty around the state this week with about half of the sites now catching moths. A field in Nobleboro was over threshold of 5 moths per week in an early field of silking corn. Another field in Warren was also over the threshold, but does not yet have corn in silk, so no spray was recommended. European corn borer feeding damage was over the 15% threshold in pre-tassel fields in Biddeford, Bowdoinham, New Gloucester, Sabattus, Livermore Falls and Nobleboro.

European Corn Borer Moth

European Corn Borer Moth, photo by David Handley

Corn Earworm Moth

Corn Earworm Moth, photo by David Handley

Corn earworm:  We are now finding corn earworm moths in most of our monitoring sites. Numbers are still low, and most fields do not yet have any silking corn that could be threatened by this pest. When more than one corn earworm moth is found at a site, all silking corn in the fields should be protected with a spray. Additional sprays are based on the average number of moths caught per week or per night (see table below). Only one field in Cape Elizabeth had moths over threshold and early silking corn. A 5-day spray interval was recommended at that location, based on a weekly moth catch of 4.

Male Fall Armyworm Moth

Male Fall Armyworm Moth, photo by David Handley

Fall armyworm:  Moths have arrived in many of the fields monitored this week, indicating that cornfields will soon start showing feeding damage from larvae. Fall armyworm caterpillars leave large ragged holes in the corn leaves and lots of sawdust-like waste within the whorl and developing tassels. We found two fields showing feeding damage this week. In silking fields, fall armyworm larvae may enter the ears through the silk channel, leaving little visible damage to the plant. For that reason, when more than 3 fall armyworm moths are caught in pheromone traps in a week a spray is recommended for all silking corn in a field. Only one field in Cape Elizabeth was over the threshold for silking corn this week. However, that same field was also on a spray schedule for corn earworm in silking corn, so no additional sprays should be required to control fall armyworm.

Japanese beetles should soon be appearing in southern and mid-state areas. These insects often find their way into cornfields and feed on the silks of developing ears, causing poor tip fill. Sprays for corn earworm (except Bt’s) will often control Japanese beetle as well.

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:  The first capture of a spotted wing drosophila in Maine was reported this week from a wild blueberry field in Blue Hill. These small fruit flies can cause serious fruit losses in raspberries, blueberries and other soft fruits. The flies will only attack fruit that has begun to ripen, and we don’t expect populations to reach damaging levels for a few weeks. For more information visit our website: http://extension.umaine.edu/highmoor/news-events/.

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

 

Sweet Corn IPM Weekly Scouting Summary

Location CEW
Moths
ECB
Moths
FAW
Moths
%Feeding
Damage
Recommendations / Comments
Biddeford 0 4 2 25% One spray recommended for ECB on pre-tassel corn
Bowdoinham 2 0 0 28% One spray recommended for ECB on pre-tassel corn
Cape Elizabeth I 1 0 0 0% No spray recommended
Cape Elizabeth II 4 0 15 0% 5-day spray interval recommended on all silking corn
Dayton 0 0 0 0% No spray recommended
Dayton II 1 0 2 2% No spray recommended
Farmington 0 1 0 3% No spray recommended
Lewiston 4 2 1 1% No spray recommended (no silking corn)
Lewiston II 0 4 1 4% (no silking corn)
Livermore Falls 0 0 0 15% One spray recommended for ECB on pre-tassel corn
Monmouth 0 0 0 0% No spray recommended
New Gloucester 1 0 1 1% No spray recommended
Nobleboro 1 10 0 18% One spray recommended for ECB on pre-tassel-silk corn
No. Berwick 1 0 1 40% One spray recommended for ECB on pre-tassel corn
Oxford 1 1 0 4% No spray recommended
Sabattus 1 0 0 38% One spray recommended for ECB on pre-tassel corn
Wales 0 0 0 8% No spray recommended
Warren 0 24 0 0% No spray recommended (no silking corn)
Wells I 0 0 0 0% No spray recommended
Wells II 0 0 1 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:
http://extension.umaine.edu/ipm/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/

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

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

Sweet Corn IPM Newsletter No. 1 – June 27, 2014

Friday, June 27th, 2014

Sweet Corn

Sweet Corn IPM Newsletter No. 1 – June 27, 2014

Click on photos to enlarge.

2014 SWEET CORN PEST SEASON BEGINS!

European Corn Borer Moths Active, Larvae Feeding in Early Corn

The 2014 University of Maine Cooperative Extension Integrated Pest Management (IPM) program for sweet corn is underway. More than twenty volunteer farms are serving as pest monitoring and demonstration sites, with fields in North Berwick, Wells, Dayton, Cape Elizabeth, New Gloucester, Poland Spring, Auburn, Lewiston, Sabattus, Nobleboro, Warren, Monmouth, Wales, Wayne, Oxford, Farmington, Levant, Stillwater, Garland and East Corinth. Pheromone traps have been set up at these farms to monitor the adult (moth) stages of European corn borer, corn earworm and fall armyworm, and we have begun scouting the fields for feeding injury by insect larvae. The information collected at these sites along with management recommendations will be shared every week during the season through this newsletter and blog. If you would prefer to receive this newsletter via e-mail, give us a call at 207.933.2100 or send an e-mail message to: pamela.stpeter@maine.edu.

European Corn Borer Scouting

European Corn Borer Scouting, photo by David Handley

SITUATION
Farmers with well-drained fields were able to get some early plantings going in spite of a rather cool, wet start to the season. Early seedings started under clear plastic or fabric row covers are now in the pre-tassel to tassel stage, with one southern field already starting to show some silk. In spite of the wet conditions during the spring, some fields are starting to get a bit dry, so the recent rain was quite welcome. Warmer weather predicted for next week should speed up plant development. European corn borer moths have been active in some fields, as evidenced by some light feeding damage we have seen in some pre-tassel fields this week.

European corn borer:  We have set up pheromone traps for European corn borer this week, and we’ll start reporting on moth activity in the next issue. We found some feeding injury and very small larvae in pre-tassel fields this week, indicating that moths are now laying eggs on the undersides of corn leaves. The egg masses are small and look like overlapping fish scales. European corn borer overwinters in Maine, and is usually the first pest to become a significant problem. To monitor corn borer, we scout 100 corn plants in each field, examining twenty plants in a row at five different locations. This provides a good estimate of the total amount of injury in a field.

European Corn Borer Moth

European Corn Borer Moth, photo by David Handley

European Corn Borer Damage on Pre-tassel Stage corn

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

In the early stages, European corn borer feeding damage looks like small “pinholes” in the leaves. Whorl stage corn only needs to be sprayed if fresh feeding injury is found on 30% or more of the plants scouted in a field. Once the corn reaches the pre-tassel stage, the control threshold is lowered to 15% because larvae feeding on the later stages are more likely to move into the ears. On the tassels, feeding damage first appears as chewing and brown waste found in the small florets. After the tassel has emerged from the stalk, the larvae chew into the stalk just below it, often causing the tassel to fall over. Sprays during the pre-tassel stage, when both moths and larvae are present, reduce the opportunity for larvae to move into the stalks and ears of the plant. Once the larvae are in the stalks they are protected from sprays. Good spray coverage of the entire plant provides the most effective kill of larvae as they move from one part of the plant to another. Rotating the type of insecticide used also improves control. Materials registered for controlling European corn borer include Bacillus thuringiensis products (XenTari®, Dipel DF®), Avaunt®, Coragen®, Warrior®, Lannate®, Baythroid®, Asana®, Radiant®, Delta Gold®, Mustang®, Sevin XLR® and Larvin®. We found corn borer feeding injury in pre-tassel fields in Sabattus, Farmington, Livermore Falls, New Gloucester and Nobleboro this week; but only the field in Nobleboro exceeded the injury threshold. Once corn reaches the silk stage, sprays may be based on the number of corn borer moths caught in pheromone traps rather than feeding injury. European corn borer moths will lay eggs on flag leaves of silking corn, and the larvae can move into the ears without leaving visible feeding injury that would be noticed when scouting. If more than five moths are caught during a week in a field with silking corn, a spray is recommended. Varieties of corn genetically modified to produce the Bt toxin (e.g. Bt corn, Attribute® varieties), should not need to be sprayed to control European corn borer.

Corn earworm:  Pheromone traps are now set up around the state to monitor the arrival of corn earworm. Corn earworm generally appears in Maine in early July, but the actual date varies greatly. The arrival of this pest is only a concern for fields with corn in the silk stage. Fields not yet in silk do not need to be protected from corn earworm. When corn earworm moths start being caught at a site, all silking corn in the fields should be protected with a spray. These moths lay eggs on the fresh silks and the larvae move directly into the ears of corn. When corn earworm moths cannot find silking corn to deposit their eggs on, they may lay eggs on the leaves of younger corn. The larvae will feed on the foliage and tassels, similar to armyworm, until the ears become available. When larvae are found feeding on younger corn, the damage is accounted for, along with any borer or armyworm damage, to determine if a spray is warranted.

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:  This is usually the last serious corn insect pest to arrive in Maine. The moths must fly in from southern over-wintering sites, and tend to lay their eggs on the youngest corn available. When the larvae hatch, they chew large, ragged holes in the leaves, and may bore into developing ears. Larvae may also move into the ears through the silk channel, behaving similarly to corn earworm. Pheromone trap catches will indicate if there is a threat to silking corn. However, corn will usually be on a spray program for corn earworm when fall armyworm is present, and both insects would be controlled.

Harstack Trap

Harstack Trap, photo by David Handley

Do-It-Yourself IPM:  To get the most accurate information about the pest situation on your farm you should monitor the fields yourself on a regular basis. Pheromone traps and lures are available that can give you an accurate, early warning of the arrival of all of the major insect pests. Traps and lures can be purchased from pest management supply companies such as Gempler’s (1.800.382.8473) or Great Lakes IPM (517.268.5693).

To learn more about IPM scouting techniques, insect identification and control thresholds, order the fact sheet Managing Insect Pests of Sweet Corn available from the University of Maine Cooperative Extension. Color pictures are provided to help with insect identification, and a chart with spray thresholds is supplied to post near your sprayer for easy reference. You can download a copy from the UMaine IPM website or call the Pest Management Office at 1.800.287.0279.

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

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

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

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

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

Friday, September 6th, 2013

Sweet Corn

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

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

Last Regular Issue for 2013

LATE SILKING CORN STILL NEEDS PROTECTION

Higher Earworm Counts in Southern and Coastal Locations

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

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

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

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

Corn Earworm Larvae

Corn Earworm Larvae, photo by David Handley

Fall Armyworm Injury on Corn Leaves

Fall Armyworm Injury on Corn Leaves, photo by David Handley

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

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

Male and Female Spotted Wing Drosophila Flies

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

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

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

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

Sweet Corn IPM Weekly Scouting Summary

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

 

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

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

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

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

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

Tuesday, September 3rd, 2013

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

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

LOW CORN PEST PRESSURE FOR LATE SEASON CORN

Higher Fall Armyworm Moth Counts in some Southern and Coastal Locations

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

Corn Harvester

Corn Harvester, photo by David Handley

European Corn Borer Moth

European Corn Borer Moth, photo by David Handley

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

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

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

Male Fall Armyworm Moth

Male Fall Armyworm Moth, photo by David Handley

Spotted Wing Drosophila on Raspberry

SWD on Raspberry, photo by David Handley.

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

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

Sincerely,

David T. Handley
Vegetable & Small Fruit Specialist

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

 

Sweet Corn IPM Weekly Scouting Summary

 

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

 

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

Corn Earworm Spray Thresholds for Pheromone Traps

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

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

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

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

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

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