Studies in cotton fields in Egypt on the effects of pheromone mating disruption on Pectinophora gossypiella (Saund.) (Lep., Gelechiidae), on the occurrence of other arthropods, and on yields

In 1999, in the Governorate of Fayum, Egypt, an organically managed area of 66 ha (33 ha of cotton) was subjected to pheromone mating disruption (MD) in order to control Pectinophora gossypiella (PBW). Tripherone-PecGos dispe nsers (Trifolio-M Comp., Lahnau, Germany), evaporating 0.7 mg pheromone per day, were applied, at a density of 300 dispensers per hectare, in mid-June when the first bolls were forming. In a neighbouring area of conventional agriculture, no PBW-MD was used. Instead, two insecticides were sprayed in the cotton fields: Profenophos in early July, and Esfenvalcrate in early Au gust. Two cotton fields (0.5-1 ha each) were studied in each area. Boll inf estation by PBW was low in the area with mating disruption, and significant ly higher in the conventionally managed cotton, prior to insecticide use (J une) and in August 1999. Bemisia tabaci, Aphis gossypii and Empoasca lybica infested conventional cotton in significantly higher numbers than organic cotton. Spiders proved to be more common in organically grown cotton (with PBW-MD) than in conventionally managed cotton (with mineral fertilizers and insecticides), The reasons of these differences are discussed. In 1998, th e cotton yield had shown no differences between organically and conventiona lly managed farms (both used insufficient PBW-MD). However, in 1999, the yi eld from the organically grown cotton (with MID) was significantly (52%) mo re than that from conventionally managed cotton (with insecticides). In thi s study, PBW-MD proved to be superior to insecticides in several aspects.