Cotton pests and their natural enemies in Madagascar

An update on the cotton pest complex and its associated natural enemies in Madagascar is provided. Since the end of the 1970s, when the previous reports had been published, the population dynamics of the principal pests in Malagasy cotton have undergone considerable changes. The American bollworm Helicoverpa armigera Hübner (Lep., Noctuidae) is still a limiting factor for production and can be considered the key pest, whereas the Egyptian leaf worm Spodoptera littoralis Boisduval (Lep., Noctuidae) and the cotton aphid Aphis gossypii Glover (Hom., Aphididae) have become significant pests as a result of indiscriminate use of synthetic pyrethroids in the 1980s. New records of beneficials, in particular the discovery of the aphidopathogenic fungus Neozygites fresenii (Nowakowski) (Entomophthorales) in cotton aphid populations, are reported. Strategies to preserve predator populations in view of reducing disruptive insecticide treatments are discussed.