Mealybugs (Hemiptera: Pseudococcidae) and their natural enemies in New Zealand vineyards from 1993-2009

Abstract

Mealybugs (Hemiptera: Pseudococcidae) and their insect natural enemies were collected from vineyards in the major winegrowing regions of New Zealand from 1993 to 2009. Mealybugs were identifi ed from 131 separate collections, and their presence on grapevines compared with that on neighbouring citrus trees in Hawke's Bay and Gisborne in 2003. Pseudococcus longispinus and P. calceolariae were the most common mealybugs found in vineyards throughout the country. Both species were present and widespread in most vineyards, and on many grape varieties, but there was often marked (and unpredictable) spatial and temporal separation. Two other mealybug species were found, each on one occasion: the exotic Pseudococcus viburni from Hawke's Bay in 1998, and the endemic Paracoccus abnormalis from Auckland in 2008. Natural enemies were collected or reared from their mealybug hosts from 51 of the collections. Seven species of parasitoids and four species of predators were commonly collected, with no apparent regional constraints. The parasitoids were: Anagyrus fusciventris, Gyranusoidea advena, Tetracnemoidea brevicornis, T. sydneyensis, T. peregrina (all Hymenoptera: Encyrtidae), Coccophagus gurneyi (Hym: Aphelinidae) and Ophelosia charlesi (Hym: Pteromalidae); and the predators were: Cryptolaemus montrouzieri, Midas pygmaeus (Coleoptera: Coccinellidae), Diadiplosis koebelei (Diptera: Cecidomyiidae) and Cryptoscenea australiensis (Neuroptera: Coniopterygidae). The faunas of vineyards and citrus orchards were similar, except that Parectromoides varipes (Hym: Encyrtidae) was collected only from citrus orchards. Linepithema humile, the Argentine ant, was collected from one Gisborne and three Hawke's Bay vineyards in 2003. The widespread presence of natural enemies shows that mealybugs are regularly attacked by both predators and parasitoids in vineyards, but additional data are required to quantify the effectiveness of biological control of mealybugs, and its contribution to limiting the spread of the economically important grapevine leafroll disease.