Soil charactristics on factors governing the existence, recycling and persistence of Bacillus thuringiensis in Egypt

The simple correlation and regression analyses showed that the soil sand percentage and the available copper levels had significant negative and positive contributions, respectively, to the abundance and distribution of B. Thuringiensis in the Egyptian agricultural soil. Among B. thuringiensis isolates, only 11.26% of the strains showed larvicidal activity against Culex pipiens. The larvicidal potency LD50 varied from 5.01 x 105 to 5.4 x 106 spores per milliliter among the isolates