Inhibition of Ovipositional Responses of Chilo partellus (Lepidoptera: Pyralidae) by the Trichomes on the Lower Leaf Surface of a Maize Cultivar

Abstract

The role of ovipositional responses of the stem borer Chilo partellus (Swinhoe) in determining resistance-susceptibility of three maize, Zea mays L., cultivars in relation to the trichome density on their leaf surfaces was investigated. The cultivars studied were Inbred A (susceptible), V-37 (resistant), and ICZ-T (resistant). The upper leaf surfaces of Inbred A and V-37 are covered with trichomes, although the density in the latter is greater than in the former. The lower leaf surfaces of both cultivars are smooth and devoid of trichomes. The cultivar ICZ-T has numerous trichomes, not only on the upper leaf surface but also on the lower leaf surface. The screenhouse and laboratory tests showed that when ICZ-T was offered as a choice versus Inbred A or V-37, the moths exhibited a strong ovipositional nonpreference to this cultivar. In no-choice tests, the moths also showed a nonpreference for ICZ-T. The number of trichomes on the upper and lower surfaces of the leaves of ICZ-T was responsible for deterring oviposition by C. partellus. Such a maize cultivar can be of great practical utility in breeding maize for resistance to C. partellus.

Zea mays, Chilo partellus, behavior