Western bean cutworm: larval movement and feeding on corn

The development and distribution of western bean cutworm (WBC) larvae on the corn plant was characterized in the field and the effect of different corn tissues on larval survival and development was investigated in lab. The studies were conducted at the UNL Haskell Agricultural Laboratory, Concord, NE during 2009, 2010 and 2011. The larval movement study experimental design was a CRBD with six blocks. The treatments were different corn growth stages: (1) pre-tassel; (2) tassel; and (3) post-tassel stage. The infestation was artificial and the plant was divided in five zones: tassel; above ear; first ear; second ear; and below ear zone. Each zone was inspected for the presence of larvae (destructive sampling in each plot). In the tassel zone, Berlese funnels were used to recover larvae. The corn tissue feeding experiment was conducted in growth chambers (25ºC and 24h light). Experimental design was a CRBD with three blocks. The treatments were different corn tissues (early whorl, late whorl, tassel, silk, pollen and silk + pollen). Statistical analysis was conducted comparing the effect of different corn tissues on larval development and effect of the corn growth stage on distribution of the larvae on the corn plant. Larval feeding was greatest on tassel tissue in the late whorl. In field conditions the initial larval instars were concentrated in upper part of the plant. Western bean cutworm larval movement as influenced by larval mixed feeding requirements is discussed.