Sugarcane Borer (Lepidoptera: Pyralidae) Damage to Maize at Four Plant Growth Stages

Abstract

Two moderately resistant varieties (‘MBRV-SWCB’ and ‘P23R’) and one susceptible variety (‘PR7925’) of maize were infested with larvae of the sugarcane borer, Diatraea saccharalis (F.), at fully extended leaf stages 4–5, 6–8, and 9–11 and flowering stage in Mexico during 1987 and 1988. In all varieties, the highest leaf-feeding damage was recorded when plants were infested at the 4–5 leaf stage and damage declined when infestation was done at later stages. Variation in leaf-feeding damage rating was greater when plants were infested at the 4–5 leaf stage. The two resistant varieties had significantly less feeding damage compared with the susceptible variety. This indicates presence of nonpreference or antibiosis or both in two resistant varieties to sugarcane borer larval feeding. Stalk and ear damage in all varieties was highest when plants were infested at 9–11 leaf stage and flowering stage, respectively. Yield of infested treatments compared with that of an uninfested treatment was reduced at all stages in all varieties; greatest reduction occurred when plants were infested at the 4–5 leaf stage. Resistant varieties had less yield reduction compared with the susceptible variety. The results suggest that, for evaluating germplasm for leaf feeding damage, stalk damage, and ear damage resistance, the optimum stages for artificial infestation under conditions in Mexico would be 6–8 leaf stage, 9–11 leaf stage, and flowering stage, respectively.

Insecta, Diatraea saccharalis, maize, damage