Effect of certain plant extracts and one conventional insecticide pirimiphos-methyl on progeny, ovicidal and residual activities of two stored product insect pests [electronic resource].

Includes references.

Laboratory investigations were carried out on the efficiency of hexane and ethanol extract of Eugenia aromatica and Pimpinella ansium against Sitophilus oryzae (L) and Callosobruchus maculatus when mixed with wheat grains and cowpea seeds comparing with the recommended insecticide, Pirimiphos-methyl (Actellic 50% EC). The obtained results showed that, LC50 and LC90 concentrations of hexane and ethanol extracts produced high adult mortality and significant reduction of progeny (F I). With the N-hexane extract, the highest reduction percentage of (F I) was recorded with E. aromatica followed by P. ansium for their LC50 and LC90, respectively, compared to Pirimiphos-methyl. The tested plant extracts with ethanol and hexane had the same order of efficiency on C. maculates. As well as S. oryzea. Also, data obtained clearly showed that, the percentage of hatching eggs was significantly reduced compared to that of the control, especially with LC90 concentrations. The cowpea seeds and wheat grains were treated by plant extract at LC90 level and exposed to adults of C. maculatu,s and S. oryzae after various periods of storage (i.e. 7 days and 1,2,3,4 and 5 months post-treatment). The two plants extracts showed significant adult mortality and reduction of (Fl) progeny of the two tested insect, species C. mac/atus and S. oryzae. After three months post-treatment, the percent mortality and adult emergence were significantly reduced with pirimiphos-methyl as compared to the ethanol and n¬hexane plant extracts against S. oryzae and C. mac/atus). After 4 and 5 months, the reduction percentages of progeny recorded with ethanol extract of E. aramatica and P. ansium for S. oryzae were 66, 30.0 and 73, 38.5 % compared to pirimiphos-methyl which gave 47 and 20.0 % after the same periods. It was 67 and 27% after 4 and 5 months on C. maculatus, respectively while the correspondent reduction percentages of ethanol extracts compared on P. ansium and E. aromatica where the reduction percentage at the same period was 81.7, 61.0 and 70.3, 54.8 %, respectively. In the case of n-hexane extracts, the reduction percentage caused by the same plants was 63.0, 35.0 and 79.8, 58 % reduction of adult emergence, respectively, at 4 and 5 months. Key Words: Plant extracts, conventional insecticide Pirimiphos-Methyl, residual activities, stored product insect oests.

Summary in Arabic.

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