Insecticidal Activity of Cleisthopholis patens (Benth) Engl and Diels (Annonaceae) Against the Stored Product Moth, Ephestia cautella (Walker) [Lepidoptera:Pyralidae], in Stored Cocoa [Theobroma cacao (L.)]Beans.

Abstract

The toxicity of powdered leaf, stem bark and root bark of “apako”, Cleisthopholis patens (Benth) Engl and Diels (Annonacea), to Ephestia cautella (Walker) was evaluated in the laboratory at 28±2°C and 75±5% RH. Four rates of each powder. 0.5, 1.0,2.0, and 3.0 g/20 g of cocoa [Theobroma cacao (L.)] beans. were tested in completely randomized design. The treatments and an untreated control were replicated three times. In another test, treated and untreated cocoa beans were infested with 30 one-day old E. cautella eggs and the numbers of hatched eggs (at day 3 post-infestation) and emerged adults (at day 40 postinfestation) were converted to percentages. Toxicity to adults generally increased with the rate of product application and duration post-treatment. At 24 h post-treatment, only the root bark caused mortality (22.8-45.3%). Mortality increased considerably thereafter reaching the peak (100%) at 72 h for 3.0 g root bark/20 g cocoa bean, and at 96 h for 2.0 g and 3.0 g stem bark. With the leaf powder. the highest mortality was 78.9% for 3.0 g/20 g cocoa bean. All parts of C. patens at 0.5-3.0 g/20 g cocoa beans completely inhibited egg hatch whereas on the untreated control the percentage of hatched eggs ranged between 73.4 and 96.7% and percentage adult emergence ranged between 60.0 and 90.0% .