|Monday, 14 January 2013 10:31|
Cook Islands is composed of 14 islands forming a land surface of 237 km². It is divided into the Southern group (8 islands), where most inhabitants live, and the sparsely populated northern group (6 islands). The main and only high volcanic island is Rarotonga (67 km², 653m), inhabited by more that half of the country's population.
Parasitoids were imported from Hawaii and released between 1927 and 1938 and in 1954 in the hope to control B. melanotus, but none became established. Early fruit fly surveys in Cook Islands were conducted in the early 1970s by Joseph and Purea. A seasonal distribution study of B. melanotus on Rarotonga was done by P. Dale and M. Purea in the early 1980's. The New Zealand Government funded early survey work.
Full time fruit fly research started in late 1990, when the Regional Fruit Fly Project posted a United Nations Volunteer, who trained the National counterpart staff until late 1993. Fruit fly activities are coordinated by the plant protection staff of the Cook Islands Ministry of Agriculture. New Zealand has contributed funding and expertise for the development of heat treatment through the Horticulture and Food Research Institute of New Zealand. A parallel project was also conducted by the Australian Centre for International Agriculture Research (ACIAR) to support research on fruit fly surveys and field control development.
The fruit fly research facility, built with funds from New Zealand Government, is located at Totokoitu Research Station. For more information, contact:
Dr Maja Poeschko, Entomologist, Ministry of Agriculture
FRUIT FLY SPECIES: There are two species. Bactrocera melanotus is native and endemic to Cook Islands. It is restricted to the Southern island group. Pacific fruit fly (Bactrocera xanthodes) was introduced to Cook Islands in the early 1970s and is now widespread in the Southern Island group. In November 2001 Queensland fruit fly (Bactrocera tryoni) was detected in Rarotonga. This was the first record of the species in Cook Islands. Its detection prompted a quick emergency response. Action was taken to eradicate the invasive species in Cook Islands. The last few flies were trapped in February 2002. Since then, no Queensland fruit fly is recorded in Cook Islands. For the declaration on the success of the Queensland fruit fly eradication program in Cook Islands, consult the SPC PPS Website.
ECONOMIC IMPORTANCE OF FRUIT FLIES: Damage assessment data in Cook islands show that B. melanotus and B. xanthodes are collectively responsible for 12% infestation on Summer papaya and 1% damage on Winter papaya.
Surveys: Established and maintained a fruit fly rearing laboratory and laboratories for holding fruit samples collected in the field and undertaking heat tolerance studies at Totokoitu Research Station. Established permanent trapping sites on five islands of the Cook Islands. Trap sites made up of one trap baited with methyl eugenol and one with Cue-lure. Collected and held in the laboratory for adult fly emergence about 3000 commercial/edible and wild/forest fruit samples since late 1990. Confirmed that there are two species of fruit flies in the Cook Islands (Tephritidae: Dacinae) (Bactrocera melanotus and B. xanthodes), and compiled host ranges for both species. Used this data as the basis for negotiations on quarantine protocols for export of fruits and vegetables.
Pest status: Confirmed that only two species are of economic importance – B. melanotus and B. xanthodes. Determined, by host surveys, the level of damage caused by fruit flies to papaya (0.85% at coloubreak to 12.4% when ripe) and avocado (< 2% at mature green stage). Cucurbits are free from fruit fly infestation.
Quarantine surveillance: Modified the initial fauna surveys into an early warning system as part of Cook Islands’ overall quarantine surveillance system. Trapping focused on high-risk locations, such as tourist resorts, urban areas, educational institutions for overseas students, markets, farming areas, diplomatic missions and ports of entry.
Laboratory colonies: Developed and adapted laboratory rearing techniques for B. melanotus and B. xanthodes in late 1990, using various artificial diets and egging devices. Papaya-based standard artificial diet was developed in Cook Islands. Completed studies on the life cycles and rates of development of B. melanotus and B. xanthodes in artificial diet and in fruits such as papaya and avocado. Completed a study comparing rates of development at different temperatures. Studied longevity and fecundity of B. melanotus and B. xanthodes in laboratory.
Field control: Conducted protein bait spray trials in papaya orchards and on guava. Developed a package for field control of fruit flies, based on sound crop hygiene and protein bait sprays. Adopted by papaya farmers and exporters as a component of export pathway to New Zealand for papaya.
Host status testing and export markets: Used the laboratory and field tests developed by the RMFFP and the New Zealand Ministry of Agriculture and Forestry (MAF) Regulatory Authority to demonstrate that mature green banana, eggplant, Birdseye chilli and squash cultivars Delica and Blue Max are non-host for B. melanotus and B. xanthodes. Birdseye chillies are exported to New Zealand on that basis.
Heat treatments and export markets (Research by Hort + Research, New Zealand): Generated and published data on the heat tolerances of early and late eggs, first instar and feeding and non-feeding third instars for B. melanotus and B. xanthodes and had these data were accepted by New Zealand. B. melanotus is so far the most heat tolerant species in the Pacific. Cook Islands was the first country in the Pacific to have a forced hot air unit for treatment of fruits for export. Undertook commercial-scale confirmatory tests for export of papaya using forced hot air and submitted research reports to New Zealand MAF for approval of the treatment. Quarantine treatment uses forced hot air to raise the core temperature of the largest fruit placed in the coolest spot in the chamber, determined by thermal mapping, to 47.2°C and hold it at that temperature for 20 minutes before hydro-cooling. Assisted Quarantine in developing quarantine pathways for export of papaya (1994) , eggplant and mango (1998) to New Zealand. From 1994 to 1998, 1500 tonnes of papaya were exported to New Zealand, using the forced hot air treatment. In 1999, 417.5 tonnes (49119 cartons) of papaya were exported. In 2000, up to the month of March, 6223 cartons, or 53 tonnes have been exported. Figures from quarantine show that about 19 tonnes or 2698 cartons of mangoes were exported between 1997 and 1999.
Development of National expertise: Published in the ACIAR Proceedings No. 76 of the Symposium on the Management of Fruit Flies in the Pacific, four scientific papers on fruit flies in Cook Islands and published a Pest Advisory leaflet on Fruit Flies in Cook Islands. Provided training to farmers and exporters and government personnel of Cook Islands on the importance of fruit flies to production and national quarantine, identification, control methods, and quarantine treatments.
Emergency response planning: Increased preparedness to detect quickly an incursion of an exotic fruit fly species and formulated an Emergency Response Plan to eradicate any newly introduced unwanted species.
Queensland fruit fly eradication: The fruit fly eradication program for Queensland fruit fly in Cook Islands has been declared a success. This program which commenced in 2001 has resulted in the timely and prompt actions of the Ministry of Agriculture authorities to contain and eradicate the 9 flies in the Quarantine area. As a result of this program several new technologies such as the distribution of fruit fly stations (BactroMAT/ Amulet C-L fruit fly stations) from a microlight aircraft was used. Details are given in the paragraph 24 below. The success of the program is also attributed to the importance of having staff trained in such technical areas as eradication programs. The outcomes of the work in Cook Islands is one of the few success stories on the eradication of a Cue-lure attracted fruit fly species.
BactroMAT C-L bait stations were distributed as part of the eradication programme of the Queensland fruit fly (Bactrocera tryoni) using a microlight aircraft in Rarotonga on 31 October 2002. The microlight aircraft was flying about 100 m above ground with a maximum altitude of 350 m and a speed of approximately 70 km/h (=19.4 m/s). To achieve a recommended spacing of approximately 40 m per bait station, each bait station was dropped every 2 seconds.
BactroMAT C-L bait stations were distributed in the mountain region surrounding Avarua on Rarotonga Island. The mountain area that needed to be covered was approximately 1,8 km2. Thin wire was used to tie a hook on each bait station so that most of them will remain suspended in trees after being dropped from the aircraft.
A 20 liter - bucket was used as a container to hold the baits during the flight. For safety reasons the bucket was tied up to the person distributing the baits. To prevent the baits from drifting out of the bucket due to the strong draft wind it was filled up only to 3 quarters. To avoid the baits from falling into the propeller the bait stations were dropped through a 1.1 m long PVC- plastic tube with a diameter of 8 cm. The tube was attached to the aircraft in such a way that the bait stations dropped below the propeller.
To complete the distribution of all bait stations, four take offs within two hours were necessary to refill the bucket with bait stations. In total, the aircraft flew nine times up and down the mountain range, parallel to the coastline, in two hours.
STATUS OF QUARANTINE SURVEILLANCE (as of October 2007): There were 21 trapping sites each with a cue-lure and one methyl eugenol trap in Rarotonga. Fruit fly surveillance carried out every 14 days. Regularly sampled fruits for research and quarantine surveillance are breadfruit, guava, mango, papaya and Syzygium apples. All trapping and host fruit survey data are compiled on Excel spreadsheets. There are fruit fly posters at the airport and the wharf, as well as quarantine bins at the airport.
Oriental Fruit Fly Eradication (2013)
First recorded in Rarotonga on 9th May 2013 when 22 males were intercepted. Later confirmed by NZ PHEL to be Bactrocera dorsalis (Oriental Fruit Fly). An Emergency Responce Plan was activated in trying to eradicate it. Later it was found that oriental fruit fly was also present in Aitutaki.
Refer to pest alert No. 47 for more information.
various reports were issued by Cook Islands ministry of agriculture outlining a detailed activities carrried out.
Download Pest Advisory Leaflet on Fruit Flies in Cook Islands in English (729 Kb)