Colonization Responses and Damage by Chilo partellus (Lepidoptera: Pyralidae) to Four Variably Resistant Cultivars of Maize

Abstract

Four maize, Zea mays L., cultivars-Inbred A, Mp704, V-37 and Poza Rica 7832—were evaluated for resistance to leaf feeding, stem feeding, and dead heart by a stem borer, Chilo parlellus (Swinhoe) (Lepidoptera: Pyralidae) in the screenhouse under artificial infestation. The responses of C. parlellus (e.g., oviposition, larval arrest and establishment, feeding, and larval growth and development) were studied in separate experiments. Foliar damage ratings, percentage stem length tunneled, and percentage of plants showing dead heart from borer attack were significantly lower on Mp704, V-37, and Poza Rica 7832 than on the susceptible Inbred A. Of the colonization responses, oviposition by C. parlellus on the plants indicated that ovipositional nonpreference contributed to the resistance of Mp704 and V-37 but not to the resistance of Poza Rica 7832. Arrest of neonate larvae on four maize cultivars indicated that orientation nonpreference contributed to the resistance of Mp704 and Poza Rica 7832 but not to the resistance of V-37. Avery low larval establishment on Mp704 contributed to its high resistance to C. parlellus , whereas response to the cultivars V-37 and Poza Rica 7832 indicated moderate resistance. Results from studies on food ingested and larval growth and development indicated a high level of antibiosis in Mp704 corresponding to its high resistance and a moderate level of antibiosis in V-37 and Poza Rica 7832 corresponding to their moderate resistance to C. parlellus . We conclude that both nonpreference and antibiosis types of resistance mechanisms occur in these culti vars.