Ovicidal and ovipositional effects of neem (Azadirachta indicaA. Juss.) extracts on rice bug,Leptocorisa chinensis(Dallas)

Ovicidal and ovipositional effects of neem (Azadirachta indica A. Juss.) extracts were tested against rice bug, Leptocorisa chinensis (Dallas), under laboratory and cage conditions, respectively. One- to three-day-old eggs were dipped in the treatments with neem extracts alone and in combination with abamectin (Aba). Treatments with 1.4% neem oil and azadirachtin (Aza) rated at 60, 120 and 180 ppm did not show significant ovicidal effects. Moderate mortality was observed in treatments with Aza at 240 ppm (25–37%) and the combination of neem oil and Aba (36–52%) at day 7, followed by treatments containing Aza in a rate-dependent manner (5–40%). Neem oil moderately reduced oviposition and performed better than Aza at 60 ppm. Adult survival and rice yield were not significantly affected by treatments with Neem oil and Aza used alone. Targeting the adult stage, both treatments did not affect rice yield and quality. Neem extracts and Aba may be used as a supplementary tool in an integrated management programme aimed at controlling rice bug.