Bahavior and control of the locust Rhammatocerus schistocercoides (Rehn, 1906) in Mato Grosso, Brazil

Abstract

During September, 1984, a locust outbreak was reported in Mato Grosso, Brazil. It was caused by a species identified Rhammatocerus schistocercoides (Rehn, 1906). The study of the biology and behavior under laboratory, greenhouse and field conditions showed that oviposition happens during October and November, and hatching of the nymphs takes place during November and December. Each instar lasts, in average, 26 days; there are five instars under Mato Grosso conditions and six instars under Brasilia conditions. This species goes into adult in April, migrates in August-September and mating happens in September-October. Feeding preference: R. schistocercoides prefers native grasses of the savanahs following plants of rice, sugar cane, corn, sorghum, pastures, and causes damage by probing on soybeans and beans. Chemical control: Five insecticides were tested on the locust control: fenitrothion, malathion, carbaril, esfenvarelate and fenvarelate. Carbaril and pyrethroids were not efficient at the tested dosages. Fenitrothion (300 g of active ingredient per ha) and malathion (800 g of i.a. por ha) showed to cause above 98% of mortality. Fenitrothion (150 g of i.a. per ha) was also tested in dillution with cotton oil (50%), showing to cause 95% of mortality.