Should Spidermites be Considered When Treating Soybean Aphid?
With drought intensifying, two-spotted spidermites may become a factor in treatment decisions. Spidermites are favored by prolonged drought. Hot, dry weather enhances spidermite reproduction, increases the quality of soybean as a host, and decreases fungal diseases on the spidermites. Infestations build up more quickly along field edges, especially near alfalfa fields where movement into soybean may be triggered by cutting the alfalfa. Spidermites work from lower leaves upwards so examine lower leaves of plants near the field edge for these minute mites (smaller than soybean aphids) or their feeding marks (minute white spots on leaves called stiples). If spidermites are found along the field edge, check plants further into the field. The presence of spidermites should be considered in selection of insecticide and when scouting for aphids. Insecticide efficacy differs between soybean aphids and spidermites. Organophosphate insecticides work better against spidermites than pyrethroid ins
