Bill Cissel, Extension Agent – Integrated Pest Management; bcissel@udel.edu
Congratulations to Jim Palermo for accurately identifying the disease in Guess the Pest Week #20 as Soybean Vein Necrosis Disease (SVNd). Jim 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 # 21, 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 #20 Answer: Soybean Vein Necrosis Disease (SVNd) – Nathan Kleczewski, Extension Specialist – Plant Pathology; nkleczew@udel.edu; @Delmarplantdoc
Soybean vein necrosis disease (SVNd) is caused by the Soybean Vein Necrosis Virus, and is the most prevalent virus infecting soybeans. This virus is transmitted by several species of thrips during the early parts of their life. After the thrips have acquired the virus, they can transmit it for the remainder of their lifespan. Symptoms typically start around veins, likely because thrips focus feeding in this area. After entering the plant, the virus replicates, and the tissues surrounding the veins turn yellow and eventually brown. Recent research demonstrated that the virus may also be moved through seed, although the role this plays in disease epidemiology is currently unknown.
Adult thrips
Thrips adult and immatures.
Research we conducted in the region indicates that SVNd is more prevalent in double cropped soybeans, and that varieties differ in susceptibility. However, it is not known if varietal differences are due to reactions of the plant to the virus, or if the plants differ in features that alter thrips feeding preference. Research we recently published with colleagues indicates that the virus may impact seed quality, and research we are conducting in the region indicates that there may be some yield impacts, although this does not appear to be significant. Thus, management of this disease currently is not recommended. However, it is important to recognize the symptoms and realize that this is not a fungal disease. Fungicides will not impact foliar symptoms.
Guess the Pest Week# 21
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