Bill Cissel, Extension Agent – Integrated Pest Management; bcissel@udel.edu
Congratulations to William Rankin for accurately identifying the insect in Guess the Pest Week #23 as soybean thrips. William will not only have his name entered into the end of season raffle for $100 gift card not once but five times, he 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! Guessing correctly will automatically enter you into a raffle for $100 gift card at the end of the season and one lucky winner will also be selected to have their name entered into the raffle five times. For Guess the Pest # 24, 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 #23: Answer is Bacterial Blight on Soybean – Nancy Gregory, Plant Diagnostician; ngregory@udel.edu
The picture shows bacterial blight on soybean, caused by Pseudomonas. Bacteria need a wound or opening to enter leaves, which often happens during rain and wind events, mechanical injury, or insect feeding. Bacteria in a film of water can also be splashed around and enter through natural openings such as stomates and hydathodes on the edges of leaves. The picture shows leaf spots that started in hydathodes on edges of leaves. Insects can carry bacteria and the bacteria can also persist on or in some seed. Bacterial diseases are favored by high temperatures and high humidity. Use of resistant cultivars and pathogen-free seed is a part of management. Diagnostic tests are recommended if unusual foliar symptoms are observed. Spots on leaves caused by bacterial pathogens often have a water-soaked appearance and sometimes have a yellow edge or halo. Microscopic examination may reveal the presence of bacteria. Bacterial blight caused by Pseudomonas is favored by cool and wet conditions and appears primarily on young foliage. Resistance is available in some cultivars. Bacterial pustule caused by Xanthomonas is usually seed-borne and is not commonly seen in the Mid-Atlantic States. Small brown raised spots of bacterial pustule may be confused with soybean brown spot (Septoria) or mistaken for soybean rust.
Guess the Pest Week #24
What is this insect?
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
