David Owens, Extension Entomologist, owensd@udel.edu
Soybean
Continue scouting for earworm, stinkbugs, bean leaf beetles, and soybean looper. Any fields treated with a pyrethroid for earworm should be re-scouted IMMEDIATLEY! We had a heavy, prolonged worm flight into soybean and in some cases, pyrethroid failure. In other cases, pyrethroids initially knocked earworm down but did not have any residual activity. Late double crop fields, especially those treated with pyrethroids, may be at risk for significant defoliation from soybean looper. NCSU’s action threshold is around 1 worm per sweep or 15% defoliation. If there are elevated loopers present, evaluate defoliation carefully as loopers tend to start in the middle of the canopy as opposed to the upper canopy. Bean leaf beetle populations typically peak this moth and can scar pods which can lead to fungal decay.
Sorghum
Continue scouting late-heading sorghum for corn earworm and sugarcane aphid. Last week we scouted several sorghum fields with widely scattered aphid hotspots. If sugarcane aphid control is deemed necessary, the only products that are effective are Sefina, Sivanto, and Transform. We also observed above threshold earworm/fall armyworm infesting one field. Besiege, Vantacor, Blackhawk, and Carbaryl are all effective on headworms.