INSECTICIDE RESISTANCE OF THE BACTERIA BACILLUS THURINGIENSIS AGAINST BACTROCERA OLEAE UNDER FIELD CONDITIONS

Abstract

The effect of two isolated Bacillus thuringiensis Bt ,HD 210 and Bt HD128. were tested against the olive fruit pest  Bactrocera oleae . data calculated , show that, the Lc50 recoded , 128  and 137 Ug/ml Bactrocera oleae treated with different concentrations of Bt ,HD 210 and Bt HD128, respectively. The experiments carried out under field conditions during two successive seasons 2015 and 2016. The results obtained show that during two panting seasons, 2015 and 2016 the infestations of the olive trees with B. oleae were significantly decreased to 11±4.2 and 30±4.2 individuals after treated with the bacteria Bt ,HD 210 and Bt HD128, respectively  as compared to 99±9.9 individuals in the control during season 2015 after 120 days of treatments. During season 2016 the infestations significantly decreased to 17±9.9 and 33±9.4 individuals after treated with the corresponding pathogens as compared to 99±8.4 individuals  in the control.

At the harvest time during season 2015, the weight of the olive fruits were significantly increased to  2777± 72.82, and 2831± 12.51 Kg/ feddan in plots treated with Bt ,HD 210 and Bt HD128, respectively as compared 2110± 12.51Kg/feddan in the control. During season 2016 the olive fruit significantly increased to Kg/ feddan in plots treated with Bt ,HD 210.