ENEMIGOS NATURALES DE LAS MOSCAS DE LOS ESTIGMAS DEL MAÍZ: Euxesta stigmatias (Loew), Chaetopsis massyla (Walker) y Eumecosommyia nubila (Wiedemann) EN GUASAVE SINALOA, MÉXICO

The flies species complex of corn, known as “stigma flies”, including the corn-silk fly, Euxesta stigmatias (Loew), Chaetopsis massyla (Walker) and Eumecosommyia nubila (Wiedemann), they have became an important pest problem in the state of Sinaloa. The damage is associated with decaying symptoms has severely affected the quality and yield of the crop. The objectives of this research project are to report sampling results on the presence of natural sources of biological control agents (parasitoids, predators, and entomopathogenic nematodes) with biological control potential capacity to manage the populations of this flies species complex. This research was conducted during the spring-summer growing season of 2011. Samples where collected for eight continuous weeks during the corn cob development and maturation. The sampled corn variety was the hybrid Asgrow Garanon. We collected predominat two wasp species belonging to the order Hymenoptera, families Pteromalidae and Eurytomidae, which are parasites to the pupa stage of corn silk fly. In addition, a wasp from the genus Spalangia spp. The latter has shown a stronger natural parasitic effect of 47% on Euxesta stigmatias (Loew). We also observed a population of the pirate bug Orius insidiosus (Say) during the months of March-July, attacking several developmental stages of the fly. Soil samples where also processed to isolate and to identify populations of possible entomopathogenic nematodes (EPN). Larvae of Galleria melonella L. where utilized as nematode traps. Populations of nematodes from three different sites where isolated from CIIDIR-IPN Unidad Sinaloa, Guasave and Maximiliano R. Lopez, all located in the Guasave. The isolated populations are included in the Rhabditidae family, genus and specie identification is still in progress. The natural enemies found have shown potential capacity to asseses them as biological control agents on the corn flies complex.