EFFECT OF CHEMICAL CONTROL ON THE ENNEOTHRIPS FLAVENS MOUL. POPULATION AND ON YIELD OF PEANUT CULTIVARS ARACHIS HIPOGAEA L.

ABSTRACT

Enneothrips flavens Moul. infestations and the yield of two recently developed peanut cultivars, along with the commercially known cultivar Tatu, were evaluated in treatments with and without contrai of this insect. The field experiments were carried out at Centro Experimental do Instituto Biológico, in Campinas, state of São Paulo, Brazil, during the 1994/95 and 1995/96 growing seasons. Thrip evaluations were made at 7- to 15-day intervals by counting the number of nymphs and adults in samples of twenty leaflets per plot. The spraying was made twice a week for treated plots. Yield evaluations were made by weighing the peanut pods harvested from the two central rows of each plot. The results showed reduction of this insect population for all cultivars when chemicaly treated. The best responses were verified in the Tatu cultivar, but without increased correspondence in the yield with the exception of cultivar IAC-Jumbo which presented in the 1995/96 season productiveness of 2,422 kg of peanut per hectare when treated and 1,198 kg without contrai.

KEY WORDS:
Enneothripsflavens ; insecticide; Arachis hipogaea ; productivity