EFFICASY OF NATURAL POPULATION OF Trichogramma WASPS AGAINST EUROPEAN CORN BORER IN FIELD MAIZE

The aim of this study was to determine the natural infestation of European corn borer (ECB) eggs by Trichogramma wasps (Hymenoptera: Trichogrammatidae) under field conditions. The experiment was set up in Osijek, Croatia in 2013. The experiment included two levels of irrigations, two nitrogen rates and two maize genotypes. Parameters of ECB feeding activity and maize tolerance (cob mass, tunnel length, number of ECB larvae per plant), as well as number of parasitized ECB eggs by Trihogramma wasps were evaluated. Genotypes were significantly different in terms of tolerance to ECB injury. In treatments with nitrogen fertilization, ECB feeding activity was increased at both nitrogen rates. Agricultural practices did not significantly affect parasitism of ECB eggs by Trichogramma. Correlation between parameters of ECB feeding activity and parasitism by Trichogramma was slight to moderate and not significant. Natural occurrence of Trichogramma wasps were not significantly affected by agricultural practices in maize, and population of these parasitoids was low significantly affect ECB feeding activity