Establishment and distribution of the rubber vine moth, Euclasta whalleyi Popescu-Gorj and Constantinescu (Lepidoptera: Pyralidae), following its release in Australia

Abstract

Between 1988 and 1991, more than 115 000 adults and larvae of the Madagascan moth Euclasta whalleyi were released in Queensland for the control of rubber vine, Cryptostegia grandiflora (Roxb.) R. Br. Establishment of the insect was not confirmed until 1995, when populations were found around Charters Towers. Surveys were subsequently made in 1995 and 1996 to assess the establishment of the insect at release sites and to estimate the distribution of the insect as a result of dispersal. Euclasta whalleyi has now established widely throughout all major infestations of rubber vine in Queensland and no further release of the insect is considered necessary. The present distribution of the moth confirmed CLIMEX predictions of its ecoclimatically favourable range in Australia being the entire area infested with rubber vine and beyond. The insect was also found on the related native vine Gymnanthera oblonga (Burm. F.) P. S. Green that had previously been identified as a potential host during host-specificity testing. Euclasta whalleyi provided another example of the delayed appearance of establishment of some introduced biocontrol agents. This suggested that surveillance should be carried out for a number of years, and possibly decades, after the release of an agent that is assumed not to have established.