Bill Cissel, Extension Agent – Integrated Pest Management; bcissel@udel.edu
Congratulations to Drew Norman for identifying the insect in this past week’s Guess the Pest and for being selected to be entered into the end of season raffle for $100 not once but five times. Everyone else who guessed correctly will also have their name entered into the raffle. Drew will also receive a FREE copy of A Farmer’s Guide to Corn Diseases. Click on the Guess the Pest logo below to participate in this week’s Guess the Pest! For Guess the Pest # 14, we will also be giving away A Farmer’s Guide To Corn Diseases ($29.95 value) to one lucky participant.
http://www.plantmanagementnetwork.org/book/cornfarmersguide/
Guess the Pest Week #13
Answer: Thrips Injury
Thrips injury to corn appears as small whitish spots or scarring, on both field corn and sweet corn. Lower leaves are more commonly affected. Grass thrips are found on corn, with winged adults and immature stages that feed by penetrating leaf cells and sucking out cell contents. Small, longitudinal, light colored scars become numerous, so that leaves look gray and dry from a distance. Most feeding takes place behind leaf sheaths, in the whorl, or on the underside of lower leaves. Damage is usually noticed under extended periods of hot, dry, windy weather when plants are moisture-stressed. No management guidelines have been established for thrips in corn, but plants with adequate soil moisture and good vigor can tolerate thrips damage. If conditions are dry, plants are gray and wilted, and thrips are present, then an insecticide treatment may be recommended. – Nancy Gregory, UD Extension Plant Diagnostician
Guess the Pest Week #14
What insect caused this damage?
To submit your guess click the Guess the Pest logo below or go to: https://docs.google.com/forms/d/e/1FAIpQLSfUPYLZnTRsol46hXmgqj8fvt5f8-JI0eEUHb3QJaNDLG_4kg/viewform?c=0&w=1
