Aspectos biológicos e comportamentais e a interação química de Bracon vulgaris Ashmead (Hymenoptera: Braconidae) e Anthonomus grandis (Boh) (Coleoptera: Curculionidae) na cultura do algodoeiro.

Abstract

The cotton boll weevil, Anthonomus grandis (Boh) stands out as the main cotton pest in the Americas region. In cotton farmings in Brazil the larval parasitoids Catolaccus grandis (Burks) and Bracon vulgaris Ashmead have great potential for biological control and reduction of the boll weevil’s population. Therefore, the use of ecologically advantageous agricultural practices that benefit natural enemies must be planned. However, due to the intensive cotton cultivation, the extensive areas and the great use of pesticides, its use is a challenge. The aim of this study was to evaluate biological aspects and the chemical ecology of B. vulgaris. For this, the biological and behavioral aspects of A. grandis parasitism by B. vulgaris were evaluated in the laboratory. In order to evaluate the chemical ecology of B vulgaris in cotton, its attraction to cotton volatiles, both constitutive and A. grandis-induced volatiles, were evaluated. To test whether B. vulgaris uses direct chemical information from its hosts to find it, the attraction of B. vulgaris to the aggregation pheromone of A. grandis was also studied. For biological aspects, the development and survival of the young phase of B. vulgaris and the functional response curve were observed. The results showed that B. vulgaris females present type II functional response curve, and that they exploit cotton volatiles induced by A. grandis herbivory in the search for larval hosts, as well as the plant volatiles induced by A. grandis’ pheromone and its pheromone alone to find the host. These results support important information that will allow to simulate the population dynamics of both species (parasitoid-pest) and the use of plant volatiles to implement A. grandis biological control programs using B. vulgaris.