Efeito do número de adultos de Trichogramma galloi Zucchi, 1988 (Hymenoptera: Trichogrammatidae) liberados em semanas sucessivas, para o controle de Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae)

Abstract

This research aimed to study the effect of Trichogramma galloi Zucchi, 1988 adults released by successive weeks, on the control of Diatraea saccharalis (Fabricius, 1794). The experiment was carried out on a sugarcane cultivar SP 79-1011, four months-old. An experimental design entirely randomized was adopted. The experiments were conducted in four subareas of 400 m2 (20 m x 20 m) separated by 20 m from each other. The experimental plots were artificially infested with twenty D. saccharalis couples once a week (two couples for cage, corresponding a ten repetition per treatment). T. galloi adults were released weekly, in the first 24 hour after infestation, in the center of each one of the subareas, as follows: a- Control (no release); b- 4,000 adults (100,000 T. galloi/hectare); c- 8,000 adults (200,000 T. galloi/hectare); d- 10,000 adults (250,000 T. galloi/hectare). The results evidenced that the amount of parasitoids released in consecutive weeks at areas infested with eggs of D. saccharalis may still maintain high levels of parasitism. The best release rates of T. galloi were between 150,000 and 175,000 parasitoids adults per hectare per week.