Abstract
An investigation was carried out on the survival and development of the larvae of Chilo zacconius Bleszynski on some resistant and susceptible rice varieties by artificially infesting the seedlings with freshly hatched borer larvae in a screenhouse. Larval survival was ? three times higher on susceptible than on resistant varieties at early instar stages. The percentage of dead larvae recorded at early days after infestation was ? three times higher on resistant than on susceptible varieties. Larvae recovered from resistant varieties were lighter in weight. Pupation and moth emergence not only started earlier on susceptible varieties but were several times higher than on resistant varieties. Among the resistant varieties antibiosis contributed significantly to the reduction of insect number.
