Antibiosis in maize (Zea maysL.) to maize borer,Chilo partellus(Swinhoe) (Pyralidae: Lepidoptera) in India

Studies on the antibiotic effect of the maize varieties Antigua Gr.1, Ganga 5, JML22, and JML605 (less susceptible), Vijay, Ageti 76, Partap, Sangam (moderately susceptible) and Basi local (more susceptible) on various aspects of the biology of the maize borer, Chilo partellus (Swinhoe) at Ludhiana during 1979 and 1980, suggested that, during both years of testing, the less susceptible varieties generally show more antibiosis. These varieties reduced larval survival (11–17%), larval weight (51–60mg/larva), pupal weight (49–52 mg/pupa), pupal formation (9–11%), egg viability (78–83%), adult longevity (47–81 h in males and 62–99 h in females) and growth index (0.3–0.4). The corresponding values for the more susceptible variety, Basi local, were 26%, 65mg/larva, 65mg/pupa, 18%, 87%, 132h in males and 137 h in females, and 0.7, respectively. The larval period (26 days) and the pupal period (6 days) were prolonged (25–31 days and 7–8 days, respectively) on Basi local; pupal survival was not affected. On the less susceptible varieties, males outnumbered females, while on the moderately susceptible and susceptible varieties, females outnumbered males. The maize borer multiplied 1.1–1.4 times in one generation on the less susceptible varieties, compared with 2–3 times on the moderately susceptible and susceptible varieties. The implications of the results are discussed.