Responses of stemborer Chilo partellus to volatiles emitted by maize landraces exposed to signal grass (Brachiria brizantha).

Abstract

This study sought to evaluate the oviposition responses of Chilo partellus (Lepidoptera: Crambidae) on maize plants exposed to Brachiaria brizantha Stapf following oviposition by C. partellus and nonexposed maize. Two Kenyan maize landraces (Jowi and Nyamula), Latin America landrace (Cuba 91) and WH505 (hybrid variety) (control) were studied. The result demonstrated that C. partellus deposited a significantly lower number of eggs and egg batches on Nyamula, Jowi and Cuba 91 maize plants exposed to B. brizantha with C. partellus eggs compared to nonexposed ones and the exposed hybrid variety. This was because they emitted electrophysiologically active compounds such as (E)-4, 8-dimethyl-1, 3, 7-nonatriene, decanal, (E)-caryophyllene, linalool, linalool (plus nananal), E-β-fernesene, methyl salicylate and (3E, 7E)-4, 8, 12-trimethyl-1, 3, 7, 11-tri-decatetraene that deterred C. partellus from ovipositing more eggs on these plants. Therefore, herbivore-induced plant volatiles (HIPVs) of B. brizantha can be employed to protect the maize crop against C. partellus.