Establishment and Damage of the Sugarcane Borer (Lepidoptera: Pyralidae) in Corn as Influenced by Plant Development

Abstract

Infestations of Diatraea saccharalis (F.) on corn caused significant yield reductions (P < 0.05) averaging 11.8, 9.9, and 14.1% per established larva per plant when infestations were initiated at early-whorl, midwhorl, and early-tassel stages of development, respectively. Although losses mainly were attributable to reductions in average ear weight, this response appears to have been caused by different types and combinations of injury in each case, i.e., stalk tunnelling for the early-whorl infestation, stalk and ear feeding for the midwhorl infestation, and ear feeding for the early-tassel infestation. Intraplant movement and feeding site selection were influenced both by plant development and by late-stage larval behavior. Most larval mortality occurred within the first 4 days after infestations, with survival stabilizing by day 9. Results indicate that tightly appressed upper leaf sheaths on the corn plant offer greater resistance (P < 0.05) to larval establishment than do leaf sheaths at and below the ear.