Effect of the neem seeds oil extract on some immature stages of the whitefly bemisia tabaci. gennadius
2009
Saleh, S.M.M. | Al-Shareef, L.A.H.
The neem seeds oil extract was tested against the immature stages (third instar larvae and pupal stage) of the insect species, Bemisia tabaci (Gennadius). The concentrations of 0.1, 0.125, 0.25, 0.3, 0.5, 1.0 and 1.5 ml / 100 ml of distilled water were used The concentration that inhibited 50% of pupal formation (IC50) from the larvae was 0.22 % When the third instar larvae and pupal stage were treated, the concentrations that inhibited 50 % of adult formation (IC5o) were 0.17 % and 0.21 %, respectively. The larvae of the whitefly were affected severely by neem seeds oil extract and died within 3 to 8 days filer treatment with 1.0% and 1.5 % concentrations. The tested concentrations of neem seeds oil extract generally produced malformations or morphological abnormalities in all the treated immature stages of B.tabaci. The adult was produced either by failure or partial emergence. Few of the adults emerged with distorted crippled wings. The female adults deposited few eggs which failed to hatch, and some of females failed to lay any eggs. This is mainly due to the failure of the rupture of longitudinal and transverse molting sutures to different stages. The neem seeds oil extract apparently acted as a growth regulator, and suppressed the build up of the whitefly B. tabaci.
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