Biological Effect of Different Concentrations of Bacillus Thurngensis Isolated From The Soils of Sawa Lake, Al Muthanna Governorate on The of Hypera postica at Different Time Periods

Abstract

Abstract This study conduct in Al-Muthanna governorate to assess five concentrations of Bacillus thurngensisagonist Hyperapostica. The results showed the presence of Bacillus thurngensisin all the studied sites of Lake Sawa in Muthanna Governorate, and the rates of its presence were close to the same sites, and the rate of its presence in those sites was 35%, and its highest rate was recorded in the north and east of the lake, as it reached 40% and the lowest amounted to 30% in the two sites south and west site. The results of the study showed that five concentrations were taken from bacterial isolates of B. thuringiensisdiffered in the rates of killing larvae, pupae and adults of the insect Hyperapostica in vitro, Where the concentrate 1.7 × 103 spore/ml was characterized by a higher killing ratecompared to the four studied concentrations, the killing rates were (75.750, 71.080, 69.79, 64,361, 49.117 and 42,060)% for the first larval instar, the second larval instar, the third larval instar, the fourth larval instar, and the pupae, respectively, and the lowest killing rate recorded 6.873% at concentration 0.64 × 107after 24 hours of treatment.