International fruit fly management study tour

Olivia travelled to Central (Guatemala) and North America (Mexico, Florida and Hawaii) to obtain knowledge and skills in mass-rearing techniques and quality management of parasitoid wasp production. She also obtained skills and techniques in procedures for inundative release of parasitoid species used in the America’s which include Australian species, hence the methods have direct value to Australian work. Olivia also engaged in novel approaches for sterile fruit fly rearing and observed methods used internationally that may be of use in Australia such as eclosion towers which reduce labour and inefficiencies in rearing.

This study tour had great relevance to two objectives of the Cooperative Research Centre for National Plant Biosecurity (CRCNPB). In terms of technical contribution the tour allowed the development of a new skill in parasitoid rearing and release which is very limited in Australia. The skills learnt also address Program 4: Impact Management by developing tools to underpin optimal and novel control strategies and Program 1: Preparedness & Prevention through enabling an increased level of preparedness for potential emergency plant pest incursions as we now have a better understanding of parasitoid biology and ecology.

This tour benefitted Olivia’s professional development as it was of direct relevance to her current collaborative research program. Olivia was exposed to first-hand in-sights into the mass rearing of parasitoids, which has allowed her to bring back a swathe of ideas to assist in and optimise the development of a future mass-rearing facility in Australia. A particular highlight was visiting the Planta Moscafruit, Tapachula, Mexico (Fig. 1), which mass-rears over 50 million parasitoids/week (Fig. 2). It has also allowed Olivia to bring back ideas for advanced technologies for rearing out sterile fruit flies, in addition to the mass release of fruit flies, including chilled adult aerial release (Fig. 3). The flies are chilled in order to package a larger number into a smaller space and to prevent the fruit flies from trampling one another.

Olivia also used this opportunity to strengthen and foster linkages with a number of the international research group’s expert in fruit fly management, particularly the use of biological control and sterile insect technique (SIT). There is certainly scope for future collaborative research in these areas.

The development of a new fruit fly management tool for Australia based on inundative parasitoid releases offers scope to markedly increase the efficacy of emergency plant pest incidents including the eradication of B. tryoni outbreaks and incursion management for exotic fruit fly species. There is every possibility that those states currently controlling B. tryoni may serve to benefit from and use inundative releases of parasitoid wasps. In addition, there is potential for some parasitoid species to be used in Australia to augment the SIT for control of the Mediterranean fruit fly, Ceratitis capitata in addition to B. tryoni. Another potential benefit of this study is that parasitoids are being considered for inundative/augmentive release in New Caledonia and other Pacific Island nations where Queensland fruit fly exists. There is, therefore, the potential for commercial production in Australia selling to these regions. The tour was also a valuable opportunity to raise the profile of CRCNPB research.
 

Fig.1. Dr Olivia Reynolds (EH Graham Centre – NSW DPI), Professor Geoff Gurr (EH Graham Centre - CSU) and PhD student Jennifer Spinner (CRCNPB) at the Planta Moscafruit, Tapachula, Mexico.

Fig. 2. The mass-rearing of over 50million parasitoids/week at the Planta Moscafruit, Tapachula, Mexico. Fruit fly larvae are placed en masse in a canister (a), which is then inserted into a cage (b) where the fruit fly larvae are exposed to the parasitoids (c).

Fig. 3. The aerial release of chilled adult sterile fruit flies in Guatemala. Loading of the chilled adult flies in a chilled container (holding 9 million fruit flies), from a refrigerated truck into the hull of an aircraft (a) for subsequent aerial release (b) by an automated auger controlled by an operator in the aircraft (c). The fruit flies are sent out through a shute underneath the aircraft and warm up as they fall and fly before reaching the ground.