Effect of Post-Treatment Temperature on the Insecticidal Activity of Melia volkensii (Gurke) Fruit Extract Against the African Migratory Locust Locusta migratoria (Reiche & Fairmaire)

Abstract

The influence of post- treatment temperature on the insecticidal activity of Melia volkensii (Gurke) fruit extract against the African migratory locust, Locusta migratoria (Reiche & Fairmaire) is reported. In laboratory tests conducted on adult locusts, the toxicity of crude 80% methanol extracts of M. volkensii fruit increased by more than 20-fold when the post-treatment temperature was raised from 15ºC to 40ºC. This temperature-dependent toxicity was observed in insects treated either topically or via injection. This phenomenon could partly explain the wide variability in efficacy of M. volkensii fruit extracts reported by different investigators