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Date released
03 December 2024

Fruit fly control in Indonesia is being transformed as individual smallholder farmers adopt a new way of controlling these insect pests that can destroy 60% or more of their mango crops.

Farmers have traditionally blanket-sprayed their mango trees with insecticide each week during the growing season to control fruit flies, but this hasn’t proved effective. The new approach involves farmers working in a coordinated way with their neighbours, using lures and fortnightly baiting to attract and kill fruit flies across larger areas.

Known as area-wide management, this approach has been trialled in Indonesia through an ACIAR-supported project over the past 6 years and is providing almost 100% control at all trial sites.

By working together, farmers overcome one of the most vexing issues of fruit fly control programs on individual farms – ongoing reinfestation from nearby farms or uncropped land where fruit flies are either not controlled or poorly controlled.

Mr Stefano De Faveri, Principal Entomologist with the Queensland Department of Agriculture and Fisheries (QDAF), leads the project for ACIAR. He and his team have worked closely with the Indonesian Ministry of Agriculture, the National Research and Innovation Agency, Gadjah Mada University and village farming communities to trial the new approach.

‘We’ve gone into places with infestation rates of 40% to 60%, and the farmers we’re working with are now down to virtually no damage at all,’ said Mr De Faveri.

Increasing incomes

Indonesian farmers in West Java typically grow the Gedong mango variety and often pick their fruit green to reduce fruit fly infestations. 

Mr De Faveri said farmers earned less for green fruit and it was still reasonably attractive to fruit flies. But with fruit fly under control, farmers can leave mangoes on the trees for longer to develop to the orangey-red blush that the market prefers. 

‘Fruit at this stage of maturity is called Gedong gincu (gincu means lipstick in Bahasa) and it is worth twice as much as green fruit. One farmer we worked with used to get only 20% of his fruit to Gedong gincu, but now he gets 100% so his business is much more profitable,’ said Mr De Faveri.

Mangoes, from farms that are part of area-wide fruit fly management programs, are achieving price premiums. Photo: Queensland Department of Agriculture and Fisheries
Mangoes, from farms that are part of area-wide fruit fly management programs, are achieving price premiums. Photo: Queensland Department of Agriculture and Fisheries

A basic economic analysis undertaken during the project showed that farmers can earn about A$900 more per hectare (ha) based solely on increased yields of saleable fruit. This is without accounting for the extra returns for the higher-valued Gedong gincu fruit. 

Along with increased yields and improved fruit quality, the project has also helped to reduce waste, and farmers in area-wide control programs are offered a premium at market.

Lures and baits

The target species for the program in Indonesia are 2 common species infesting mango crops – oriental fruit fly (Bactrocera dorsalis) and carambola fruit fly (Bactrocera carambolae).

Lures made of fibreboard blocks laced with methyl eugenol as an attractant and insecticide kill male fruit flies. Two lures are placed in every hectare within the program boundaries, rather than just within crops.

Training workshop participants learned how to make lure blocks and baits used in area-wide control programs for fruit fly. Photo: ACIAR
Training workshop participants learned how to make lure blocks and baits used in area-wide control programs for fruit fly. Photo: ACIAR
Workshop participants use the newly launched training guide and field manual to hang traps that attract male fruit fly. Photo: ACIAR
Workshop participants use the newly launched training guide and field manual to hang traps that attract male fruit fly. Photo: ACIAR
Hanging traps used to attract and catch male fruit flies.

Mango tree foliage is also spot-sprayed every fortnight during the cropping season using a protein bait combined with insecticide applied at low rates.

This uses considerably less insecticide compared with conventional weekly blanket spraying of all mango trees across the growing season. Targeting foliage with the sprays also helps to prevent pesticide residues and blemishes on fruit.

Mr De Faveri said the current project refined earlier research, also supported by ACIAR, which developed the lures and baits used. Improvements include halving the rate of protein in the baits and halving the number of lures needed per hectare, which has reduced the costs of the control program.

Expansion in Indonesia

The project has 3 trial sites for area-wide management: 24 ha in Sedong Lor (West Java), 40 ha in Krasak (Central Java) and 33 ha in Mekarjaya (West Java). 

While the project officially ends this year, Mr De Faveri said partners in Indonesia were already expanding the approach to other mango-farming communities and to farmers growing similar crops that are affected by the same fruit-fly species.

The Indonesian Agency of Agricultural Research and Development (Badan Standardisasi Instrumen Pertanian: BSIP), led by Mr Hendri Boekittinggi, has expanded the original Mekarjaya site in West Java from 33 ha to 75 ha. BSIP is also working with 3 villages in East Java to establish sites of about 25 ha each. 

The Directorate of Horticulture Protection (DHP) within Indonesia’s Ministry of Agriculture is also adapting and expanding area-wide management to new areas and crops. These include 363 ha of mangoes in West Java, 288 ha of citrus in North Sumatra and 552 ha of snake fruit in North Sumatra and Central Java.

Mrs Nelly Saptayanti, in her role as Plant Protection Officer with the DHP, helps to identify areas for potential expansion of the area-wide management and said farmers’ commitment greatly influenced the success of implementation.

Many farmers think that only their land needs to be saved, even though fruit flies can reach distant areas and have many host plants. Fruit flies are always present throughout the year because of the availability of hosts.

Mrs Nelly Saptayanti 
Plant Protection Officer 
Directorate of Horticulture Protection 

She estimated losses caused by fruit-fly damage to Indonesia’s mango and other tropical fruit crops at more than IDR10 trillion, or A$100 million a year. Fruit fly is also a quarantine ‘pest of concern’ for countries importing Indonesian fruit, including Australia.

Mrs Saptayanti said expanding area-wide management is essential to protect the country’s domestic fruit sector and export markets.

International expansion

Two major outputs from the project include a training manual in establishing an area-wide management program for fruit fly in mango, and a 5-day training workshop for international participants, both designed to help share the approach with other Indo-Pacific countries.

The workshop was held in Indonesia in May 2024, with entomologists and extension officers attending from Australia, Fiji, Indonesia, Malaysia, Papua New Guinea, Philippines, Timor-Leste, Thailand, Tuvalu and Vietnam.

Workshop participants in Indonesia as part of an ACIAR-funded project to develop area-wide management approaches for fruit flies.
Workshop participants in Indonesia as part of an ACIAR-funded project to develop area-wide management approaches for fruit flies.

The event was developed and coordinated by QDAF to provide practical training in running an area-wide control program. It also allowed participants to share the challenges they faced with insect pests in their own countries.

ACIAR manager for this project, Horticulture Program Research Officer Mikayla Hyland-Wood, was one of the attendees.

She said the training manual – Area-wide management of methyl eugenol-attracted fruit flies in mango: A systems approach – was launched at the workshop, and there had already been requests for translations into different languages. 

‘The ACIAR project was focused on one crop and two pests, predominantly in Indonesia. But there was a lot of enthusiasm at the workshop about adapting the area-wide approach to different crops and pests, which is an important outcome,’ said Ms Hyland-Wood.

Authors celebrate the launch of their training manual and field guide, Area-wide management of methyl eugenol-attracted fruit flies in mango: A systems approach, at a recent workshop in Indonesia. Photo: ACIAR
ACIAR's Mikayla Hyland-Wood (back row left) joins the authors in celebrating the launch of a training manual and field guide, Area-wide management of methyl eugenol-attracted fruit flies in mango: A systems approach, at a recent workshop in Indonesia. Photo: ACIAR

‘For me, this was one of the most exciting aspects of the workshop and the project –seeing people actively engaged in how they could use this approach to tackle pest issues in their own countries. Sharing this knowledge will significantly extend the benefits of the ACIAR investment.’ 

ACIAR Project: ‘Development of area-wide management approaches for fruit flies in mango for Indonesia, Philippines, Australia and the Asia-Pacific region’ (HORT/2015/043)

Biosecurity
Fruit fly