Contarinia gossypii Felt (Diptera: Cecidomyildae) NEW PLAGUE OF COTTON

Abstract

Malformations of flower buds and squares followed by a drop of structu­res, and in many cases by necrosis caused by Pseudomonas sp., were observed during the 1983-1984 cotton growing season. Symptoms were observed on the top third of eighty days old cotton plants. Losses were estimated at 700 Kg/ha. of cottonseed. The problem was associated with a pinkish larva that feeds on the androgens; up to 185 of these larvae were counted in a square of six mm in diameter; the mature larvae are 2 mm long. The insect was identified as Contarinia gossypii Felt. The larvae leave. the structure by means of a characteristic jump and pupate few millimeters beneath the soil surface, where it is difficult to find them. The pupae are of the object type, dark, 1.2 mm long, and protect­ed by a Silke cocoon. The adults are topic cecidomyds with very long antennae and legs and covered by dense dark hairs, that give them the appearance of grayish midges. They are approximately 1-2 mm long. Laboratory observations indicate that the emergency occurs in the late afternoon. As a natural enemy was found a platygasterid parasite larvae. Up to now, cotton has been the only plant found as host for this pest. C. gossypii larvae were collected in cotton fields in a widespread area of Córdoba during February-April 1984.