Biolep^® is a biological pesticide containing spores and protein crystals of the pathogenic bacterium Bacillus thuringiensis subsp. kurstaki. This insecticide specifically targets the larval stage of several species of Lepidopteran pests. When Btk is eaten by a susceptible larva, the toxin is released in the alkaline environment of the lepidopteran larva’s gut, destroying the midgut wall, paralysing the gut and causing the larva to stop feeding within minutes. The destruction of the midgut wall allows the bacteria to enter the blood of the target insect, causing full-scale infection and death of the insect. This process can take 24-48 hours. Biolep^® is a digestive pesticide and is sprayed on the aerial parts of plants. It is therefore very suitable for controlling stem and leaf-feeding pests that spend at least part of their larval period outside of the plant tissue.