This will be the final issue of the Sweet Corn IPM Newsletter for the 2007 season. I would like to thank all of the growers who participated in the program this year, and our team of IPM scouts including Vanessa Fereshethian, Kristina Severance, Kim McNelly, Gary Wonder and Sean McAuley. Special thanks to Tisha Palleschi and Jonathan Hillier who coordinated the team. We’ll be sending out an evaluation form for this newsletter and our sweet corn IPM program later this fall. Please take the time to fill it out and return it to us. Your input is needed to be sure that this program provides you with the most pertinent, practical and reliable information possible.

SITUATION
Although the end of the sweet corn season is in sight, sales and supply are still strong in many locations. The price has held well during the season, and quality and yield have been very good, although late ear size has been smaller than normal in some non-irrigated fields. Pest pressure continues to be high in most sites this week, especially in southern and coastal Maine. Growers who still have corn in the field should be vigilant, and keep silking corn protected.

European Corn Borer: Pheromone trap catches have been generally lower this week. Dayton, Sabattus, Warren and Wells had 5 or more moths in traps this week, which exceeds the spray threshold for silking corn. However, all locations are under a spray interval for corn earworm, so no additional spray is necessary.

Corn Earworm: With few exceptions, corn earworm catches in pheromone traps have been very high this week, especially in southern and coastal areas. Any fresh silking corn remaining in fields needs protection at this time. A six day spray interval for silking corn was recommended in one Lewiston location. A five day spray interval was recommended in Warren. A four day spray interval was recommended in Biddeford, East Corinth, Jefferson, Levant, Monmouth, New Gloucester, Nobleboro, Palmyra, Poland, Sabattus, Wayne and Wells. A three day interval was recommended in Cape Elizabeth, Corinth, Dayton, Dresden, and North Berwick. Predicted warmer temperatures for this weekend are likely to increase moth activity, so it is important to protect any fresh silking corn now.

Fall Armyworm: Fall armyworm moth counts were also among the highest we’ve seen this season. Nearly all locations had 3 or more moths in the traps, which would justify a spray to protect silking corn. All of these locations are under spray intervals for corn earworm, so no additional sprays should be necessary.

Growers Twilight Meeting at Highmoor Farm
A reminder to visit Highmoor Farm, Maine Agricultural and Forest Experiment Station on Wednesday September 12 at 5 p.m. to join us for a twilight meeting to tour the vegetable research plots. Growers will be able to visit muskmelon and pumpkin variety trials, our high tunnel tomato trial, strawberry trials and more. Extension Specialists Mark Hutton and David Handley will be on hand to discuss the trials and answer questions. Hope to see you there!


Sincerely,
David T. Handley
Vegetable & Small Fruit Specialist

Highmoor Farm 
P.O. Box 179 
Monmouth, ME 04259 
(207) 933-2100      

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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. Pheromone traps and lures can be purchased from pest management supply companies such as Gempler's in Mt. Horeb, Wisconsin (1-800-382-8473) or Great Lakes IPM in Vestaburg, Michigan (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. For copies of this free publication contact the Pest Management Office at 1- 800-287-0279.

IPM Web Pages:
http://pmo.umext.maine.edu/default.htm
http://pronewengland.org/
http://www.pestwatch.psu.edu/sweet_corn.htm
http://www.umass.edu/umext/ipm/
http://www.nysipm.cornell.edu/vegetables.html

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Sweet Corn IPM Weekly Scouting Summary
 

CEW: Corn Earworm (only fresh silking corn should be sprayed for this insect)
ECB: European Corn Borer
FAW: Fall Armyworm

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.
 

Corn Earworm Spray Thresholds for Pheromone traps

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