Biology and behaviour of Tetracnemoidea brevicornis: a biological control agent for invasive mealybugs in New Zealand

Abstract

Pseudococcus calceolariae and P. longispinus are two species of mealybug that are invasive in New Zealand. They are considered to be significant agricultural pests as they damage and contaminate crops and are also able to vector Grapevine leafroll-associated virus 3. Since their establishment in New Zealand, a number of natural enemies from the mealybugs’ native ranges have become self-introduced. Within the community of mealybug enemies are a suite of parasitoid species which are remarkably under researched. These parasitoids may have the potential to be employed as augmentative biological control agents against pest mealybugs on crops. Tetracnemoidea brevicornis is one of those species. The main objective of this research is to study the biology and behaviour of T. brevicornis and identify this species’ potential as an augmentative biological control agent for P. calceolariae and P. longispinus. Chapter 2 identifies that T. brevicornis is able to develop from egg to adult between 15 and 30°C, with an optimal temperature estimated to be 27°C. Chapter 3 predicts that this species of parasitoid should be present throughout the majority of the North Island and the north and east of the South Island of New Zealand due to the ecoclimatic suitability of these areas. Chapter 4 indicates that laboratory population of T. brevicornis has an olfactory preference for P. calceolariae of 2nd and 3rd instar. Finally, although the number of parasitoids collected in the field were low, the field survey results presented in Chapter 5 found only Anagyrus fusciventris, Ophelosia bifasciata, and Coccophagus gurneyi at the site, despite the site being suitable for T. brevicornis.