Sudden death syndrome, soybean vein necrosis virus found in fields
Fields in southeast Barton County and northeast Jasper County were scouted on Sept. 5 by Wyatt Miller, an agronomy assistant with University of Missouri Extension in Barton County.
A few soybean podworms were seen, but below threshold levels. Soybean podworm treatment is justified when larvae exceed one per linear foot of row and 5 percent or more of pods are damaged.
Sudden death syndrome was seen in a field scouted this week. Symptoms begin as scattered yellow blotches in interveinal leaf tissue that soon increase in size. Leaf veins typically stay green, allowing the bright yellow blotches to stand out.
"Sudden death syndrome is associated with wet conditions and will therefore be found mainly in irrigated fields this year. Producers should select for sudden death resistant varieties for fields with sudden death syndrome history," said Miller.
Miller also found what appears to be Soybean Vein Necrosis Virus in a couple of fields. Soybean vein necrosis virus is relatively new and is spread by thrips. Initially, small light-green to yellow patches develop near main leaf veins. As the disease progresses, these areas turn reddish-brown with browning of the veins.
"Most fields across the state have low to moderate disease symptoms. Currently little is known about the virus and there is no recommended control measures," said Miller.