To evaluate the effects of pre- and post-harvest burning on larval and egg parasitoids of Diatraea saccharalis (Fabr.) on sugarcane two harvesting systems were studied for two consecutive seasons (92/93 and 93/94), i.e., half of the area was burned (CQ), whereas the other half was not burned before mechanical harvesting(CC). In CQ, all trash remaining in the field after harvesting was also burned. After the 92/93 harvesting, and for two years, larvae of D.saccharalis were collected from both areas with intervals of three months. They were maintained in the laboratory on artificial diet for 15 days, to estimate the parasitism rates. During the same period, evaluations of parasitism on D. saccharalis eggs were made monthly on egg masses, obtained from caged pairs, in the field. These eggs remained on the leaves for a week. The medium larval parasitisms of D. saccharalis, during two years of observations, were 40 and 19.7 % for CC and CQ, while the egg parasitisms were 20.5 and 13.4 % for CC and CQ, respectively. We concluded that pre- and post-harvesting burning of sugarcane affects negatively the population of larval parasitoids of D.saccharalis [Metagonistylum minense Townsend, Paratheresia claripalpis Wulp and Cotesia flavipes (Cameron), especially the last one, as well as its egg parasitoids (Trichogramma spp.).
Insecta; parasitoids; sugarcane borer
