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Comparative effect of neem seed kernel extract and two synthetic insecticides against the new major pest of sorghum, Poophilus costalis in Togo

Agboyi L.K., Martin T., Ketoh G.K., Glitho I.A.. 2013. In : Joshua O. Ogendo ; Catherie W. Lukhoba ; Philip K. Bett ; Alex K.. Proceedings of The First International Conference on Pesticidal Plants (ICPP) Vol.1 : Harnessing pesticidal plant technologies for improved livelihoods, Nairobi, Kenya, 21-24 january 2013. Egerton : Egerton university, p. 15-19. International Conference on Pesticidal Plants (ICPP). 1, 2013-01-21/2013-01-24, Nairobi (Kenya).

Since 2001 in Northern Togo, most varieties of sorghum are damaged by severe attacks of the new major pest Poophilus costalis (Walker) (Hemiptera: Aphrophoridae). This pest was not important for sorghum before 2001. Both adults and larvae feed on leaves of Sorghum by sucking the sap. The symptoms are chlorosis and necrosis of sorghum leaves. Severe attack could induce in farm 100% crop losses. Bioassays with a field population of P. costalis were conducted in laboratory to compare the efficacy of crude aque ous Neem ( Azadirachta indica ) Seed Kernel Extract (local material) to chemicals, cypermethrin and carbofuran. Field experiments were carried out at the same time in research station. In laboratory, the three insecticides were tested against the third insta rs (L 3 ) of P. costalis but, in field, all the stages were observed. The result indicated a lower efficacy of Neem Kernel Extract, compared to cypermethrin and carbofuran to control P. costalis . The LC 50 for Neem Kernel was 16.34 g seed kernel/l and those of cypermethrin and carbofuran were 2.26 mg/l and 6/80 mg/l respectively/ On field experiment, the concentration of 50 g/l of Neem kernel ( ? 0/16-0.31 g azadirachtin), 0.31 g/l of Cypermethrin and 0.004 g/m 2 of Carbofuran contributed to reduce the population of P. costalis by 73%, 87% and 94% respectively. Compared to the synthetic insecticides, Neem Seed Kernel extract could be a natural alternative for sorghum protection against P. costalis . Further field experiments are necessary to study the effect of neem seed kernel extract on secondary pests and useful insect.

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