Submitted to: Journal of Applied Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 9, 2008
Publication Date: March 3, 2009
Citation: Chang, C.L. 2009. Fruit Fly Liquid Larval Diet Technology Transfer and Update. Journal of Applied Entomology. 133: 164-173 Interpretive Summary: Fruit flies are one of the greatest impediments to fresh produce exports world wide. There are some 100 pest species of fruit flies world-wide, the majority of which thrive in the Asia-Pacific Region. Crop losses from 40 – 100% are experienced everywhere from villages to large area farming systems. A significant result of this loss is the lower dietary nutrition levels, reduced incomes for farmers, and heavy use of pesticides in many countries. Crop losses caused by fruit flies have become a major concern, as evidenced by recent UN/FAO data, which indicates that by 2020 there must be a 70% increase in world food production in order to prevent major famine. A group of scientists in Hawaii, from USDA-ARS, APHIS, HDOA, and UH, Manoa has implemented an Area Wide Pest Management (AWPM) program to suppress the fruit fly population in Hawaii since 2000. The technologies developed within this program have been transferred to many parts of the world that share Hawaii’s fruit fly problems. One of the most important components of the AWPM program is a well-established rearing technology to mass produce fruit flies, in order to support the Sterilization Insect Technique (SIT) program. USDA-ARS scientists have recently developed a liquid larval rearing diet, using sponge cloth to replace biological bulking agents -- such as wheat products, to rear medfly, oriental fruit fly and melon fruit fly larvae, and to reduce or eliminate the spent diet management problem. The technology transfer components necessary to propagate this program include, development of diet formulation for each species, identification of tray sizes/types/stacks, quantification of egg density/tray/area/ diet, clarification of environmental conditions for rearing (i.e., temperature/humidity/ light), mating competitiveness in field, selection of main protein source, and quality control/life history of insects reared from this technology. The latter has been evaluated based on the following parameters: pupal recovery, larval developmental period, pupal weight, adult emergence, adult flier, mating, egg production, and egg hatch. Fruit flies reared on a liquid diet have been identified, evaluated and proved to have competitive mating performance in comparison to the conventional control diet. The components that exhibit the optimal performance of fruit flies raised on a liquid diet are expected to be recommended before this technology could be physically transferred or implemented to mass rearing facilities worldwide. This manuscript is to report the recommended components of optimal performance, procedures to implement this technology in a mass-rear scale, and the current status of technology transfer worldwide.
Technical Abstract: Since October 2006, USDA-ARS has been implementing a fruit fly liquid larval diet technology transfer, which has proceeded according to the following steps: (1) Recruitment of interested groups through request; (2) Establishment of the Material Transfer Agreement (MTA) with ARS; (3) Fruit fly liquid larval diet starter kit sent to the requestor for preliminary evaluation; (4) Problem-solving through email or onsite demonstration; (5) Assessment on feedback from the participants to decide whether to continue the project. Up to date, the project has involved 35 participants from 29 countries and 26 species of fruit flies. Fourteen participants have concluded their evaluation of the process, and 11 out of these 14 have deemed it to be successful. One participant has decided to implement the project on a larger scale. The 14 participants were, Argentina (Ceratitis capitata and Anastrepha fraterculus), Bangladesh (Bactrocera cucurbitae, C. capitata, and B. dorsalis), China (Fujia province) (B. dorsalis), Italy (C. capitata), Fiji (B. passiflorae), Kenya (B. invadens, C. cosyra), Mauritius (B. zonata and B. cucurbitae), Mexico (Anastrepha species), Philippines (B. philippinese), Thailand (B. correcta), Austria (C. capitata, Vienna 8 and A. fraterculus), Israel (Dacus ciliatus and C. capitata), South Africa (C. capitata, Vienna 8) and Australia (C. capitata). The Stellenbosch medfly mass-rearing facility in South Africa and the CDFA in Hawaii were two mass-scale rearing facilities that allowed us to demonstrate onsite rearing in a larger scale. Demonstrations were performed in CDFA in 2007, and in Stellenbosch, South Africa in 2008; both were found to be successful. The Stellenbosch medfly mass-rearing facility in South Africa decided to adopt the technology and is currently evaluating quality control of the flies that were reared as larvae on a liquid diet. between irradiated DTWP-LD strains in competition with non-irradiated standard lab strain or DTWP-MF strain in Boller’s cages. These findings indicate that: (1) the quality of DTWP may be less capable in mating than the standard lab strain and wild strain; and (2) liquid diet reared larvae can produce adults of equal mating ability compared to adults reared on a conventional diet. Liquid diet reared fruit flies should therefore be ready for mass scale rearing for SIT programs following the completion of other field quality control tests, including those measuring dispersal abilities.