CORRELATION EVIDENCE BETWEEN COTTON PEST POPULATION FLUCTUATION AND SOME CLIMATIC FACTORS IN GOIÂNIA, GOIÁS, BRAZIL 1974 - 1975

Abstract

A survey of some of the insect pests which attack the cotton crop in Goiânia County, State of Goiás, was undertaken to verify the possible influence of meteorological factors, such as rain and temperature, on the populational fluctuations of the following species: Alabama argillacea (Huebn., 1818) (Lepidoptera-Noctuidae); Heliothis virescens (Fabr., 1871) (Lepidoptera-Noctuidae); Platyedra (Pectinophora) gossypiella (Saund., 1844) - (Lepidoptera-Gelechiidae); Scaptocoris divergens (Froesch., 1960) - ( Hemiptera-Cydnidae). The insects were collected through the use of light traps, of the “Luiz de Queiroz” type, using fluorescent light bulbs. The meteorological data of the region were also computed. The correlations between the meteorological data and the populational fluctuations of the studied species were calculated. The results indicated that Alabama argillacea appeared during the entire year with acme population observed in March. By means of the obtained correlation, it was determined that the rainfall was beneficial to the high population of this insect pest; Heliothis virencen, appeared from January to July, with three population peaks, in April, May, and June. The correlation in regard to the monthly average temperature was negative and it was observed that temperatures declining from 16° to 12°C were beneficial to the high population of this insect. Platyedra gossypiella appeared from February to September with maximum population in March and April. Neither rain nor average temperature were influential in the population distribution of this insect. Scaptocoris divergens appeared from November to May, with acme population in January and February. Only rain was significantly beneficial to this high population.