Behaviour of the sugar-cane borer, Diatraea spp. in the State of Rio de Janeiro during the 3-year period 1975--77.
Laboratory and field studies were carried out in Rio de Janeiro, Brazil, on Diatraea spp., the major pests of sugar-cane there, and the parasite complex associated with the borer. The dominant species was D. saccharalis (F.), but D. flavipennella (Box)was also present. Infestation was heaviest in sugar-cane plantations in the Macae ecological region, where it considerably reduced yields. Infestation was consistently low in the lowlands, and this is attributed to the higher level of natural parasitism there than elsewhere in the region. The larval parasites reared were Metagonistylum minense Tns., Paratheresia claripalpis (Wulp)., Ipobracon spp. and an unidentified ichneumonid; M. minense was the most abundant parasite and attacked more than 60% of the larvae in the lowland areas. Hyperparasitism by indigenous tachinids was rare.Parasitism of the eggs by Trichogramma minutum Ril. played a large part in natural biological control. Telenomus alecto (J.C. Crawford) was found only rarely. Promising results were obtained in attempts to establish Apanteles flavipes (Cam.) and it is suggested that this parasite should be released in areas in the state where natural parasitism is not sufficiently high to afford adequate control.