Pezothrips kellyanus (Thysanoptera: Thripidae) nymphs on orange fruit: importance of the second generation for its management

Abstract

Kelly's citrus thrips Pezothrips kellyanus (Bagnall) (Thysanoptera: Thripidae) is a new pest of oranges in New Zealand, southern Australia, and the Mediterranean Basin. The nymphs of this thrips can damage the fruit from petal fall up to 6 wk later. Because there is a lack of information on its management, the aims of this study were to determine the number of generations occurring on the fruit and the efficacy of 3 insecticides (chlorpyrifos, spinosad, and spirotetramat) to control this pest. Chlorpyrifos and spinosad displayed a high efficacy against nymphs and reduced significantly the percentage of damaged fruit when a single generation of P. kellyanus attacked the fruit. However, these insecticides did not prevent development of a subsequent generation of P. kellyanus. The percentage of damaged fruit was higher when the 2nd generation was present. Spirotetramat did not display a knockdown effect, and its efficacy was less than that of chlorpyrifos and spinosad. Similar to these insecticides, spirotetramat did not prevent the attack of a 2nd generation when it occurred. Additionally, we analyzed the side effects of these treatments on predatory mites. Spinosad and spirotetramat negatively affected these beneficial species.