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Abstract Laboratory experiments were carried out to study the efficacy of bacterial commercial insecticides of Bacillus thuringiensis (Berliner) namely Florbac, Bactospeine and Delfin on the different growth stages of the pink bollworm, Pectinophora gossypiella (Saunders). The treated stages included eggs, first and fourth larval instars and adults of P. gossypiella. Each of these stages was treated with different concentrations of the bioinsecticides and data were recorded from the tested and subsequent stages and included mortalities, malformations, egg -laying activity of the resulting adults and hatchability precentages amongst the deposited eggs. Studies extended also to include the haemolymph of P. gossypiella larvae, and inspections involved the total haemocyte counts (THCs), differential haemocyte COlUltS(DHCs), haemolymph viscosity and blood volume of treated and control larvae. The obtained results may be summarized as follows: I - Effect on different growth stages of P.gossypiella : 1.1. Eggs’ treatment: The pink bollworm eggs were exposed to different concentrations of each of the three bioinsecticides after about 24 and 72 hours of deposition. I.1.A. Effect on hatchability : The effect of eggs’ treatment after one and three days of deposition with either of Florbac, Bactospeine or Delfin were, statistically, insignificant (88 - 92, 86 -92 and 92% for eggs treated one and 3 days after deposition and UIl1Ie*d eggs, respectively) . ._._------ 105 1.1. B. Effect on survival of hatched larvae: Amongst the hatched larvae, significantly, higher mortality percentages were recorded amongst those resulted from treated eggs than control. More effect was, generally, detected amongst larvae that hatched from eggs treated at 3 days than those treated at one day. The effect on larval mortality appeared as a concentration dependent; i.e., increased by the increase of the applied concentration. I.I.e. Effect on pupal and adult mortality and malformations: The percentages of successful pupation were negatively correlated with the applied concentration. That was more evident amongst pupae resulted from eggs treated after 3 days of deposition (95.65 -I 00, 91. 18 - 97.67 and 92 - 97.30/0 pupation by applying the maxima and minima doses of Florbac, Bactospeine and Delfin, respectively). Moths emergence was also affected due to eggs! treatment. Few larvae, pupae and adults were found malformed. 1.1.D. Effect on larval period: Treatment of 24 and 72 hours old eggs with either of Florbac, Bactospeine and Delfin at different concentrations resulted in significant prolongation in the duration of the hatched larvae than control (18.75 _ 19.25, 18.51 - 18.79 and 18.37 -18.95 days, respectively, opposedto 15.77 days in case of the control larvae). I.I.E. Effect on pupal period : Significant prolongations in the pupal period were also detected due to previous treatment with bioinsecticides at different concentrations (9.4 - 11.89, 9.62 -11.39 and 9.83 -11.64 days, respectively) than control (6.26 days). |