Thermal requirements and estimation of number of generations per year of sugarcane borer in four localities of the state of São Paulo, Brazil

Estudou-se a biologia da broca-da-cana-de-açúcar (Diatraea saccharalis Fabricius, 1794) (Lepidoptera-Pyralidae), em dieta artificial, em cinco temperaturas constantes (20, 22, 25, 30 e 32°C) visando determinar as exigências térmicas das diferentes fases de desenvolvimento do inseto. As constantes térmicas para as fases de ovo, lagarta, pupa e adulto foram, respectivamente: 67,47; 516,96; 126,08 e 172,02 graus-dias (GD), sendo as temperaturas-bases das quatro fases (ovo, lagarta, pupa e adulto) 11,2; 7,3; 10,6 e 7,1°C. Com base nas exigências térmicas das diferentes fases biológicas do inseto, estimou-se que a praga pode apresentar cinco gerações anuais completas nas localidades de Piracicaba, Ribeirão Preto, Jaú e Pindorama, no Estado de São Paulo. The biology of sugarcane borer (Diatraea saccharalis Fabricius, 1794) (Lepidoptera: Pyralidae) was studied in the laboratory on an artificial diet and under five constant temperatures (20, 22, 25, 30 and 32°C) with the objective to determine the thermal requirements of the development stages of the insect. The thermal requirements for the egg, larval, pupal and adult phases were, respectively, 67.47; 516.96; 126.08 and 172.02 degree-days (DG) while the threshold temperatures for the four phases were 11.2; 7.3; 10.6 and 7.1°C, calculated by the coeficient of variation method. Based on the thermal requirements of the different insect phases, it was estimated that the pest can complete five generations per year in ten localities of Piracicaba, Ribeirão Preto, Jaú and Pindorama in the state of São Paulo, Brazil.