Avaliação da incidência do afídeo vector da doença vírus de topo em leque da bananeira e prospeção de potenciais insectos vectores

Abstract

Banana production is of great commercial importance in Mozambique as it is a source of income, however, significant losses have been recorded due to pests and diseases such as the Banana Bunchy Top virus (BBTV), a viral disease whose known vector is the aphid Pentalonia nigronervosa. BBTV disease is present in southern Mozambique, specifically in the districts of Chókwé and Manhiça. The growing threat of the disease's expansion was one of the important factors for the development of this study, which focused on evaluating the incidence of the aphid vector of the banana fan top virus disease and prospecting for possible insect vectors of the disease. The work was carried out at the administrative post of Ilha Josina Machel, in neighborhoods 2, 3, 4, and 1 de Maio (in the Maguiguana locality) and neighborhood 6 and Matchedje (in the Zonguene locality). In banana plants with symptoms of the disease, the infestation and density of the vector P. nigronervosa were determined, and other sucking insects associated with infected banana plants and some surrounding weeds with symptoms of the disease were surveyed. The collected samples were preserved in 70% ethanol followed by virus detection. The results showed that the aphid P. nigronervosa infested on average 24% to 62% of plants with symptoms of the disease, with average densities ranging from 1 to 25 aphids/plant. Neighborhoods 2, 3, 4, 6, and 1 de Maio (in the town of Maguiguana) had a significantly higher density compared to neighborhoods 6 and Matchedje (in the town of Zonguene). Other sucking insects were identified, associated with banana plants with symptoms of the disease, belonging to the order Hemiptera represented by the families Pentatomidae, Reduvidae and Afididae. The highest density of other sucking insects was observed in Pentalonia caladii aphids, and the lowest in bedbugs, whose average varied from 0.65 and 0.72 individuals per plant, respectively. The detection of the BBTV virus in aphids (Pentalonia nigronervosa) and other suckers provided positive results for samples 4, 5 and 8 using different primers, more specific for the detection of the BBTV virus. On the other hand, negative results were recorded, probably due to the absence of the BBTV virus in the insects at the time of sample collection, since P. nigronervosa requires hours to acquire it.