Identification of ecotypes of Trichogramma spp, as an biocontroller in corn crops in the province of Santa Elena

Abstract

In corn production, one of the limiting factors are phytosanitary problems, such as the stem borer (Diatraea spp) and the fall armyworm (Spodoptera frugiperda). Historically, broad-spectrum insecticides have been used to control harmful insects, generating the emergence of resistance in the pest, high economic cost and negative impact on human health and the environment. To reduce the negative effect, it is necessary to constantly develop research into alternative control. Within biological control, Trichogramma species are widely used as parasitoids of pest insect eggs in different crops through release and population increase. The present research aims to disseminate information about the existence and distribution of the parasitoid located in various communities in the province, and also highlight its importance as an alternative to control lepidopteran populations. It was carried out with the objective of identifying the species and zonal ecotypes of Trichogramma spp, and its effectiveness as a biological control agent in corn cultivation in the province of Santa Elena. To collect ovipositions, we worked with corn plots that met the selection criteria, the species of the parasitoid Trichogramma dendrolimi was identified and the percentage of natural parasitism was calculated. The establishment and maintenance of the breeding stock was carried out with the parasitoids that were born from the collected postures, a total of 13 ecotypes corresponding to 13 places were obtained, additionally a comparison ecotype is included that corresponds to Trichogramma prentiosum, and serves as a reference. or control. The ecotypes were evaluated in laboratory conditions at a temperature of 28 ± 1°C, humidity of 73 ± 5% and a photoperiod of 12:12 hours. Through biological parameters such as percentage of parasitism on artificial host, percentage of birth, percentage of atypical individuals, sexual ratio and viability of parasitized eggs in refrigeration. Highlighting that several of the ecotypes presented greater potential as biocontrollers, the main ones being E2LAS belonging to the Colonche parish, Loma Alta commune, El Suspiro precinct and E9JDP belonging to the Julio Moreno parish, Juntas del Pacifico commune. Those that can be considered as candidates for release in biological control programs.