Diversity of the parasitoids of Bemisia tabaci B-biotype (Hemiptera: Aleyrodidae) in Guadeloupe island (West Indies)

Bemisia tabaci (Gennadius) (B-biotype) was introduced in the Caribbean in the late 1980s. This new pest drastically changed plant protection management in this region, because of direct damages on cucurbits and transmission of numerous begomoviruses on tomatoes and beans. Parasitoids have been reported for the A-biotype B. tabaci and other species of whiteflies. After the introduction of the new biotype, a few additionnal surveys of associated parasitoids were conducted. To assess the importance of the parasitoid complex of B. tabaci in a Caribbean island, we monitored the parasitoid populations in Guadeloupe in three locations that varied by climatic and agroecological conditions. Three host-plants species were sampled monthly continually for parasitized B. tabaci nymphs during 4 yr. Different phenologic stages of the host plants were present throughout the study. The nymphs were reared in laboratory, and data on the emerging parasitoids and whiteflies were recorded. In every locality, the most common species was Encarsia sophia (Girault and Dodd). This species was not recorded in Guadeloupe before 1997, and it may have displaced other parasitoid species. The greatest diversity and efficiency of parasitoids occurred in agrosystems including diverse crops on small plots, with little pesticide use and with the proximity of a natural forest. Species of the parasitoids composition changed during the 4 yr of the study, suggesting a progressive adaptation of the indigenous parasitoid fauna -after the introduction of E. sophia. (Résumé d'auteur