English abstract
Extracts of eight plants, namely Qarat, Acacia nilotica, Mustafal, Annona squamosa; Shereesh, Azadirachta indica; Luban, Boswellia sacra; Kheshkhash, Crotolaria juncea; Zebrot, Jatropha dhofarica; Yas, Myrtus communis and Suwwad, Suaeda aegyptiaca were prepared by steeping 12.5 gm of shaded dried leaf / seed powder of each plant in 12,5 ml water and 50 ml of methanol or ethanol solvents in addition to commercial neem. The extracts were suction filtered and tested for their insecticidal, repellency and growth inhibition properties against pulse beetles, Callosobruchus chinensis Linn. The growth inhibition properties were studied by observing the number of eggs laid on kidney-bean seeds, adult emergence and mortality of adults exposed to these seeds treated with different extracts. The extracts from the seeds of A. squamosa caused 100% mortality of beetles within 20 and 4 hours of their exposure to ethanol and methanol extract films respectively. The other extracts which caused high mortality (>70%) were from the plants of A. nilotica, C. juncea, M. communis and S. aegyptiaca in methanol and B. sacra, J. dhofarica, S. aegyptiaca and commercial neem in ethanol solvent extracts. The extracts of M. communis in methanol showed high repellency to the beetles compared to other extracts. A. squamosa treated seeds attracted the beetles resulting in a high mortality of the beetles rather than repelling them, thus showing different mode of action of : A. squamosa from other extracts. The number of eggs laid and the adult emergence from seeds treated with extracts prepared from ethanol were significantly less (P<0.05) than those seeds treated with methanol extracts. The mortality of beetles emerged from seeds treated with A. squamosa was 100% within 2 and 6 days in ethanol and methanol extracts respectively.
