Figure 1. The effect of the presence of insect hosts and biopesticide application on bacterial abundance of the Bacillus cereus group in experimental enclosures.

Populations of host insects (P. xylostella) were established in host addition cages six weeks before the first sampling time point (time point 0). Soil samples were taken immediately before the application of a B. t. kurstaki biopesticidal spray (DiPel DF) (time point T0) and then at 10 and 28 days after spray application. Leaf samples were taken at time points T10 and T28 only. Treatment labels insect/no insect indicate the experimental exclusion of Lepidopteran hosts or the experimental addition of diamondback moth populations; the labels spray/no spray indicate the application or absence of biopesticide. The data are colony-forming units per gram of sampled material from leaf and soil samples (two samples per experimental cage, twenty four cages in all). Data are means ± SEs.