Influence of females intraspecific competition and lack of host on Telenomus remus Nixon (Hymenoptera, Scelionidae) parasitism on Spodoptera frugiperda (J. E. Smith) (Lepidoptera, Noctuidae) eggs

摘要

Influence of females intraspecific competition and lack of host on Telenomus remus Nixon (Hymenoptera, Scelionidae) parasitism on Spodoptera frugiperda (J. E. Smith) (Lepidoptera, Noctuidae) eggs. Intraspecific competition and lack of host can affect the success of biological control programs. Thus, this work aimed at evaluating the effect of different densities of females (1, 3, 6, and 9 females/100 eggs) and the absence of host in the parasitism of Telenomus remus Nixon (Hymenoptera, Scelionidae) on Spodoptera frugiperda (J.E. Smith) (Lepidoptera, Noctuidae) eggs. It was observed an increase in egg parasitism of S. frugiperda by T remus beyond a density of 3 females/100 eggs under laboratory (18%) and field (32%) conditions, although the parasitism caused by densities greater than I female/100 eggs was not significantly different. However, this did not cause superparasitism. On the other hand, the number of females in the progeny was lower (39%) as density of females increased, but it was not observed in field conditions. Even after nine days of host absence there was no significant reduction in the parasitism which was ca. 95 eggs/female/day. However, a decrease in the number of parasitized eggs (40%) could be observed on the 10th day. Therefore. the release of three females per 100-egg mass is adequate for high levels of parasitism.