Abstract: The invention concerns crop protection, in particular the prevention and treatment of infestations of agricultural crops by pest insects, such as insects belonging to the Thysanoptera order (Thrips). The invention is predicated on the finding that thrips sensitive crops benefit significantly from treatment with a biological crop protection agent derived from (industrial) insect farming by-products. Treatments of the invention not only result in an overall reduction in the number of thrips on the crop (as compared to untreated crop), but also in an overall increase in crop yield and quality. The invention provides the crop protection agent, methods of treating agricultural and/or horticultural crop using the crop protection agent and uses of said crop protection agent for treating agricultural and/or horticultural crop.