Large-scale Field Trials of Imidacloprid for Control of the Spined Citrus Bug

Abstract

Four large-scale field trials were carried out in 2001 and 2002 in lemon orchards in south-western New South Wales to assess the suitability of imidacloprid as a replacement for endosulfan in controlling the spined citrus bug (SCB), Biprorulus bibax Breddin (Hemiptera: Pentatomidae). The results showed that imidacloprid was at least as effective as endosulfan in controlling SCB, even when it was applied at a rate corresponding to half of its discriminate dose (100% kill). The application of imidacloprid did not reduce numbers of wasps and spiders foraging in tree canopies. However, imidacloprid was more toxic than endosulfan to parasitoids of the red scale and to lacewings. These negative effects can be minimised by timing the sprays in winter, when SCB adults congregate in neighbouring orange trees and the numbers of natural enemies of citrus pests are generally low.