David Owens, Extension Entomologist, owensd@udel.edu
Soybeans
Continue scouting for corn earworm in double crop wheat beans. Last week, I wrote an article about how to use the corn earworm threshold calculator for when soybean value is above 10 dollars per bushel and also how to factor in potential secondary costs that might be incurred by spraying a field for earworm. Check it out.
Green stink bug activity has picked up considerably in the Georgetown and Harrington blacklight rap locations. Reports of increased stink bug activity in R6 beans came in this week. Once we move into the R6.5 stage where bean seed separates in the pod, stink bug thresholds rise from 5 per 15 sweeps to about 7 per 15 sweeps. At this stage, yield loss is less likely, but they can still cause significant quality damage. In Plenish beans where quality is more important, and basis higher, it may be worth treated at lower thresholds.
Sorghum
Scattered earworm hotspots have been detected in late sorghum. You can scout for earworms by shaking heads into a bucket to dislodge the worms. Texas AM has a great sorghum threshold calculator as well. Isolated hotspots of sugarcane aphid, particularly in sorghum that is just now heading, are being found. Scout carefully. If 20-30% of plants are infested and honeydew is present, it may be worthwhile to consider a treatment. The most effective two insecticides are Sivanto Prime (3 fl oz), and Closer or Transform. Hopefully we will not hit threshold this year.