Efficiency of Bacillus thuringiensis for biological control of date lesser moth (Batrachedra amydraula) in field conditions

The lesser moth, Batrachedra amydraula is one of the most important pests of Dates. The aim of this study was to investigate the efficiency of Bacillus thuringiensis to control this pest in Date palm plantation condition. Krustaki bacterial isolate was used. The split plot design was used to conduct the research. Main plots consisted of three times of treatments including same time, three days and a week after the appearance of the pest. Sub plots were three different concentrations medium, average and maximum including One-tenth, equal and ten times of LD50 given 2 days and continued for a week. The experiment consisted of four replicates on a Sayer Date palm tree. A chemical control (Diazinon insecticide) and a treated without the chemical and biological control was considered as control group. Percentage of damaged fruit as the symptoms of biological pest activity were been sampling from mid-April once every two weeks of treatment. The results showed that there were significant differences between treatments, so that the maximum infection was recorded on minimum concentration at 3 and 7 days after the lesser moth appearance. The minimum infestation was recorded on maximum concentration and there were no significant differences between the three different times of release. The lowest average growth rate and the highest average reduction of injury growth rate were recorded on maximum concentration and coincided with the pest emergence treatment. The highest performance control was recorded on the maximum concentration coincided with the emergence.