Pulgões, cochonilhas e inimigos naturais associados a cultivos de hortaliças e plantas espontâneas na ilha de São Luís, Maranhão, Brasil

Abstract

Aphids and scale insects are insects that feed directly on the sap of plants and cause serious damage with impacts on production. Due to the economic importance of these pests for vegetables, this work was conducted with the objective of inventorying the species of aphids and scale insects as well as their natural enemies associated with the cultivation of vegetables and spontaneous plants, and to study the population fluctuation of these arthropods in Maranhão Island, Brazil. The research was carried out in areas of family farmers, in the municipalities of São José de Ribamar, Paço do Lumiar and Raposa. Samples were collected monthly and carried out directly on the infested plants, with 16 vegetables and six spontaneous plants. Nine species of scale insects were recorded, five of aphids and 47 of natural enemies; 43 new interactions of natural enemies with aphids and scale insects. Two parasitoids, Aenasius mitchellae and Aenasius flandersi were registered for the first time in Brazil. Five species of pests were considered predominant because they had the highest faunal indexes: Aphis gossypii, Lipaphis pseudobrassicae, Maconellicoccus hirsutus, Phenacoccus solenopsis and Phenacoccus sp.3; among the natural enemies were: Aphidius sp., Anagyrus kamali, Allotropa scutellata, Diomus leondai and Syrphidae. The vegetables Abelmoschus esculentus and Hibiscus sabdariffa are the most infested by aphids and mealybugs in the study regions. The association of Ph. solenopsis on Chenopodium ambrosioides, Jatropha gossypiifolia, P. oleracea and Sida sp.; and Praelongorthezia praelonga on J. gossypiifolia; and the aphid Ap. nerii on Calotropis procera. The population peaks of aphids, cocoids and natural enemies occurred in the dry season and the lowest abundances in the rainy season. There was a negative correlation for the species A. craccivora, A. gossypii, L. pseudobrassicae and P. solenopsis with rainfall and relative humidity; however, for natural enemies there was not correlation. In addition, a description of a new coccinellid species of the genus Diomus was recorded.