Predatory effect of Orius sp. (Hemiptera: Anthocoridae) on the density of Thrips palmi KARNY (Thysanoptera: Thripidae) on eggplant.

Abstract

The predatory effect of Orius sp. on the population density of Thrips palmi was evaluated on potted aubergines in a screenhouse. As the predator was killed by spraying with fenthion, which did not affect the population density of the thrips, young plants with both T. palmi and Orius sp. were treated with the insecticide to evaluate the effect of Orius sp. The population density of the pest on treated plants increased rapidly, while the density on untreated plants remained at a very low level. One adult and 5 nymphs of Orius sp. at a density of 1.2/leaf were released on young potted plants infested with about 60 T. palmi/leaf. After 13 days the population density of the thrips had decreased to 0.3/leaf, corresponding to 1.5% of the rate on plants on which the predator had not been released. It is concluded that the introduction of Orius sp. lowered the population density of T. palmi on aubergines.