A DISEASE OF PALE WESTERN CUTWORMS (LEPIDOPTERA: NOCTUIDAE) REARED IN THE LABORATORY

Abstract

After successfully rearing the pale western cutworm, Agrotis orthogonia Morrison, for years in the laboratory such severe mortality developed in the colonies that further nutritional studies were impossible. The symptoms and effects of the disease syndrome are described. Neither steam sterilization of food and rearing equipment nor use of antibiotics in the food prevented disease. A bacterium tentatively identified as Pseudomonas aeruginosa was isolated from dead insects and when injected or fed to healthy larvae caused the disease. Use of a ’clean room’ and associated aseptic techniques for rearing the insects reduced the numbers of microorganisms in the environment and again permitted the pale western cutworm to be reared successfully.