RESISTANCE MECHANISMS OF SUGARCANE TO MEXICAN RICE BORER (LEPIDOPTERA, PYRALIDAE)

Larval antibiosis and adult and larval nonpreference studies were comp ared with field screening studies to determine the sugarcane character s and mechanisms that may confer resistance against the Mexican rice b orer, Eoreuma loftini (Dyar). Larval antibiosis results of diet incorp oration bioassays suggest tile presence of antinutritional components or allelochemicals in some genotypes. Differences in adult oviposition among genotypes in laboratory greenhouse, and field studies were slig ht; therefore, ovipositional preference is probably not important in c onferring resistance. Laboratory experiments indicated that difference s in larval establishment could be an important resistance character. Field results confirmed earlier research that sugarcane genotypes vary in their level of injury to this pest. However, field results did not always compare favorably with laboratory results, suggesting that sev eral mechanisms of resistance may be important in this sugarcane-stalk borer system.