Capacidade de dispersão e parasitismo de Tetrastichus howardi (Hymenoptera: eulophidae) em pupas de Diatraea saccharalis (Lepidoptera: crambidae) na cultura da cana-de-açúcar

Abstract

The knowledge of the number of parasitoids to be released in the field and their dispersal capacity can increase the chances of success in the biological control programs. The borer sugarcane is one of the most important pests of sugarcane in Brazil and their natural enemies are responsible for population regulation in the field. The aim of this study was to estimate the number of female parasitoid Tetrastischus howardi (Hymenoptera: Eulophidae) per pupa of Diatraea saccharalis (Lepidoptera: Crambidae) and its ability to spread the sugarcane culture. Pupae of D. saccharalis were introduced in internodes of stalks and spread the sugarcane culture. Females of T. howardi were released at the midpoint of the plot, except to the witness, and pupae of D. saccharalis collected after 96 hours. The highest percentage of parasitism (46.39%) was observed when using 102 females of T. howardi per pupa of D. saccharalis. Females of T. howardi found and parasitized pupae of D. saccharalis up to 20 meters from the release point. The average dispersal distance in the canesugar culture was 7.64 m, with an area of 80.07 m2 dispersion. Initially, releases of T. howardi should be performed at 125 points per hectare so that a homogeneous distribution closer to the culture of sugarcane with up to seven months of sprouting from biological control of D. saccharalis.