Effectiveness of the botanical insecticide azadirachtin against tirathaba rufivena (Lepidoptera: Pyralidae)

Abstract

Tirathaba rufivena Walker (Lepidoptera: Pyralidae) is an important pest of areca palm, Areca catechu L. (Arecaceae), in China. The effects of azadirachtin on the development and mortality of T. rufivena were determined. All larval instars were susceptible to azadirachtin, but the stomach and contact toxicities diminished as the larvae matured. The LC25 and LC50 dosages had no effect on larval hatch when applied directly to the eggs on different days after deposition, but the LC90 treatment retarded hatch from eggs treated 1 to 3 d after deposition. The tested concentrations significantly affected the survival of neonate larvae from treated eggs, especially larvae that emerged from eggs treated 3 d after deposition. Azadirachtin also prolonged larval development and duration of the pupal stage. The percentage of adult emergence decreased, and longevity of the emerged adults was shortened, following treatment. Also, egg production and viability from females treated as larvae with azadirachtin were significantly affected.