Bruggmanniella perseae Gagné (Diptera, Cecidomyiidae) and its associated parasitoids in avocado in Nayarit, Mexico

Abstract

Two species of gall midges have been associated with the deformation of small avocado fruits in several Central American countries. In recent years, similar symptoms were detected in a small avocado-producing region in Nayarit, Mexico. Therefore, the objective of this study was to identify the insect species associated with those avocado damage symptoms and its natural enemies. Sampling was conducted during the main flowering and initial fruit set period across five sites. A total of 944 deformed fruits, 1 to 2 cm in diameter, were collected and kept in 500 ml plastic containers to await the emergence of flies and parasitoids. Fruits from which no insect emergence occurred were dissected. This information was used to estimate the parasitism rate. In the study area, only Bruggmanniella perseae Gagné, 2004 (Diptera, Cecidomyiidae) was identified infesting avocado fruits of Hass and Mendez varieties. Furthermore, four genera and six species of parasitoids were recovered. The highest parasitism rate was recorded in the Mendez variety (31.49%). The highest parasitism rate (16.69%) was caused by Rileya insularis (Ashmead, 1894) (Chalcidoidea, Eurytomidae), followed by Torymus umbilicatus (Gahan, 1919) (Chalcidoidea, Torymidae), and two species of Galeopsomyia Girault, 1916 [ G. perseae Hansson, 2023 and G. gonzalezi Hansson, 2023 (Chalcidoidea, Eulophidae)]. This work provides the first characterization of the male of G. perseae and includes images to facilitate identification of all recovered parasitoid species.