Survey of mealybugs and their parasitoids in south-east Queensland citrus

Abstract

Mealybugs in Queensland citrus receive regular control measures, but have never been surveyed for species composition or for their associated parasitoids. We collected infested fruits regularly between February 1994 and May 1995 at Mundubbera, Nambour, and Brisbane in south-east Queensland. More than 650 fruits and twigs were sampled from citrus trees and nearby plants. The citrus mealybug, Planococcus citri (Risso) (Hemiptera: Pseudococcidae), accounted for virtually all mealybugs collected. Most were recorded at Mundubbera in December and January. Ten species of hymenopteran parasitoids were recovered. The pteromalid Ophelosia sp. and four Encyrtidae (Anagyms sp., Coccidoxenoides peregrinus (Timberlake), Leptomastidae abnormis (Girault) and Leptomastix dactylopii Howard) were the most common species and are primary parasitoids of mealybugs. A hyperparasitic signiphorid, Chartocerus sp., was also present, as were males of an unidentified encyrtid species with indeterminate host relationships. The three remaining species were Aphelinidae (Myiocnema comperei Ashmead, Euryishia sp., Coccophagus sp.) and were uncommon in samples. Parasitism was never higher than 3%. Most individuals (97%) were collected in Mundubbera where all parasitoid species were present. Anagyrus sp., C. peregrinus, L. abnormis and Chartocerus sp. each contributed between 17 and 23% of all wasps recovered at Mundubbera, with the dominant species varying with sampling occasion.