Effect of Some essential oils and ethanol plant extracts on adult of Cowpea beetle (Callosobruchus maculatus Fab.)

Abstract

The study was carried out in the laboratory of pesticides in Plant Production Dept. Faculty of agriculture / Damascus Unv. during 2017-2018 . The study aimed to evaluate the efficacy of essential oils and ethanol plant extracts obtained by steam distillation from fruits of Chinaberry (Melia azedarach L.), seed of Castor (Ricinus communis L.), and leaves of Oregano (Origanum vulgare L.) and Thyme(Thymus vulgare L.) on adult of Callosobruchus maculatus Fab.( Coleoptera: Bruchidae), and compared with chlorpyriphos ethyl insecticides. Bioassays, i.e. fumigation action with pure essential oils and insecticide were carried out on adult. Results showed that the LC₅₀ values obtained for 48 h were, 54.19 , 58.98, 99.55 and 162.51 µL/ L air for Oregano, Chinaberry, Castor and Thyme respectively. Where, he LC₅₀=3.92 ppm values for chlorpyriphos ethyl. Bioassays, i.e. seed treatment of Chickpea (Cicer arietinum L.) with ethanol plant extracts were carried out on adult. Results showed that the LC₅₀ values obtained for 7 days were, 5.62 , 6.90, 8.08 and 8.44 ml/ Kg seed for Oregano, Chinaberry, Castor and Thyme respectively. Where, the LC₅₀=2.57 ppm values for chlorpyriphos ethyl. Results proved that the essential oil and ethanol extract of Oregano leaves significantly superior  on the all other treatments  in both fumigation action and seed treatment on the adult of C. maculates, followed by Chinaberry. Efficacy of the tested essential oils and ethanol plant extracts of the tested plant and chlorpyriphos ethyl insecticides increased by increase the concentrations and exposure time.