Dr Natalia Medeiros De Souza1, Dr Sybilla Oczkowicz1, Dr Patricia Chay1, Dr Carole Wright2, Mrs. Pauline Wyatt3

1Department Of Agriculture and Fisheries, 21-23 Redden Street, Cairns, Australia, 2Department Of Agriculture and Fisheries, 28 Peters St, Mareeba, Australia, 3Department Of Agriculture and Fisheries, 41 Boggo Road, Dutton Park, Australia

Biography:

Natalia is an Entomologist, working with fruit flies of economic importance for the Department of Agriculture and Fisheries in Cairns.

Abstract:

Cold disinfestation is a key phytosanitary treatment in the international trade of fresh commodities. Access to protocol markets is heavily regulated and research to support market access follows strict guidelines, one of the main requirements is that no survivors are found in a minimum of 30,000 insects treated. According to the International Plant Protection Convention Phytosanitary Measures Research Group, when assessing a treated commodity “the number of live and dead larvae should be recorded”, which may be difficult and inaccurate depending on the level of insect decay post treatment. Small-scale trials were conducted to determine the reliability of the assessment process and whether the practice of counting dead larval bodies in treated fruit can be rationalised. We infested blueberries with a known number of eggs of Bactrocera tryoni and cold treated all immature stages, controls were kept untreated. Control and treated fruit were held at 26°C to allow survivors to develop into third instars, fruit were then dissected, and all individuals were counted, and numbers compared. Results so far showed that, for first and second instar larvae, basing infestation rates and subsequent estimates of treated insects on the recovery of live and dead larvae in the treated fruit may result in overly conservative numbers when compared to those derived from control fruit. Furthermore, assessment of early larval stages in decaying fruit was laborious and extensively time consuming which may increase the likelihood of larval decay and an additional difficulty in larger scale experiments targeting 30,000 insects.