Effects of Bacillus thuringiensis aizawai, NeemAzal-T/S and Spinosad on Potato Tuber Moth, Phthorimea operculella (Zeller) (Lepidoptera:Gelechiidae)

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Hiba Bushra Hamad Humaida
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University of khartoum
The experiments were carried out at Shambat in the laboratory of Crop Protection, Faculty of Agriculture, University of Khartoum in the period from March to April 2006. The main objective of the experiment was to investigate the biological effects of three biopesticides namely NeemAzal, Spinosad and Bacillus thuriengiensis on 2nd and 3rd larval instars of the tuber moth Phthorimaea opeiculella (Zeller). The products were used as stomach poison as well as topical ovicides and larvicides. Ovicidal treatments rates were replicated four times on groups of 25 eggs and four different concentrations of Bacillus thuriengiensis 1.6mg/500ml, 1.0mg/500ml, 0.8mg/500ml and 0.5mg/500ml, NeemAzal and Spinosad 1.6ml/500ml, 1.0ml/500ml, 0.8ml/500ml and 0.5ml/500ml for each of the three products were tested as ovicides. Parameters such as hatchability, deformation were taken to judge the performance profile of these biopesticides. The three products caused non significantly different effects on the egg hatchability when applied topically. Two application rates for each product were used as follows as stomach posion:NeemAzal (1.75ml/litre, 0.87ml/litre), Spinosad (1.6ml/litre, 0.8ml/litre) and Bacillus thuriengiensis (1.6gm/litre, 0.8gm/litre). Three slices of potato were put in each Petri dish after being dipped in the respective products. Untreated and treated insects were observed for mortality or developmental effects. On the other hand, different concentrations of all the three products resulted in 100% mortality on the second instar larvae. However, mean percentage mortality of 82.8%, 74.1% and 100% was achieved on the third instar larvae, by Bacillus thuriengiensis, NeemAzal and Spinosad respectively. A dose-dependant mortality was also achieved when the three products were applied in the recommended rate and sub dose. The recommended dose caused a percentage mortality of 100%, 100% and 74% for the Spinosad, Bacillus thuriengiensis and NeemAzal respectively while the sub dose caused percentage mortality of 100%, 93% and 89.3%. The three products were used to measure mortality percentage and body weight in the 3rd instar, mean percentage of morality was 37.2%,40.1%and 39.2% for Bacillus thuriengiensis , Spinosad and NeemAzal respectively when used 0.01/5ml. However the dose 0.05/5ml was caused mortality percentage 43.1%,42.1%and 44.0% for the products respectively. The two doses appeared that there are a significant different in body weight 0.25mg, 0.24mg and 0.25mg as compared to the control 0.30mg.
A thesis submitted to the University of Khartoum in partial fulfillment for the requirements of the Degree of Master of Science in crop Protection
Bacillus thuringiensis var. aizawai NeemAzal -T/S Potato Tuber Moth Crop protection University of Khartoum
Hiba Bushra Hamad Humaida, Effects of Bacillus thuringiensis aizawai, NeemAzal-T/S and Spinosad on Potato Tuber Moth, Phthorimea operculella (Zeller) (Lepidoptera:Gelechiidae). – Khartoum : University of Khartoum, 2007. - 49 P. : illus., 28 cm., M.Sc.