Plathypena scabra (F.) (Lepidoptera: Noctuidae) populations and the incidence of natural enemies in four soybean tillage systems

Soybeans were planted in four widely used tillage systems (fall-moldboard-plow, fall-chisel-plow, till-plant, and no-till) and monitored for insect populations of the green cloverworm (GCW) Plathypena scabra , populations, its parasitoids, and the presence of the entomopathogenic fungus, Nomuraea rileyi Samson. Each tillage regime was used to plant soybeans in randomized complete blocks; blocks were replicated three times. Weekly shake-cloth samples were taken in each tillage plot. Each collected GVW larva was maintained singly in a 26-ml plastic snap-top vial containing a soybean leaflet until its death or adult emergence. Analysis of variance detected that significantly fewer (P < 0.05) GCW larvae were collected from till-plant and no-till soybean plots than from fall-moldboard-plow and fall-chisel-plow plots during the first year of the study.