Alternative fruit fly solutions for mango growers’ trialled

Queensland Department of Agriculture, Fisheries and Forestry (QDAFF) researchers are looking for better ways to protect mangoes from fruit fly. They have set-up farm trials on the Atherton Tablelands and at Bowen to evaluate whether male lures and female baits are a viable alternative to orchard cover sprays for fruit fly control.

Project leader Stefano De Faveri, who is based at Mareeba, said the project follows on from the success of similar trials in Indonesia.

“Over the three years of research in Indonesia, fruit fly populations have been reduced by up to 99.5% where lures and baits were trialled, compared with areas where conventional insecticides were used. This equates to less than one fly per monitoring trap per day caught in the trial area, compared with up to 600 flies per trap per day in the sprayed area.

“Before the Indonesian trials, we were not sure if this concept would work in tropical areas where pest fruit flies are endemic, but the research has proved that they are applicable to more regions than first thought.

“Because of improved fruit fly control, Indonesian farmers are seeing increased yield and fruit quality, and are enjoying a significant boost to their household income. We are now trialling the system in north Queensland against local fruit fly species, and hope to see similar benefits passed onto Australian farmers,” Mr De Faveri said.

Fruit fly control in north Queensland has relied on cheap and effective insecticide cover sprays. However, these sprays kill beneficial insects which keep other pests such as mango scale and mites under control. As the use of agricultural chemicals becomes more restricted by Government regulations and markets increasingly demand residue-free fruit, the use of insecticide cover sprays is becoming less acceptable to farmers.

EuriGold’s Dale Williams’ property in Bowen was used as a trial site. “So far, the project appears successful. “The number of flies caught in the traps shows the numbers are reducing. The application of the baits is definitely achievable, and was not too problematic or time consuming.

“Although we have never had any major issues with fruit fly on our property, we wanted to get involved to find solutions to an issue that faces the whole industry. If the project is successful, hopefully we’ll see reduced reliance on chemicals and greater opportunities for market access,” Mr Williams said.

To adapt the system to mangoes, researchers must develop a practical method of killing the female fruit fly. Because the female needs protein to mature her eggs, bait made from yeast plus an insecticide are commonly used as a band spray on the foliage of the tree to attract and kill.

Project researcher Pat O’Farrell said that the commercially available yeasts produce a pink skin blemish when sprayed on mango fruit which might lead to downgrading of fruit quality.

“An important part of the research is to find yeast products that do not affect the fruit, ways to apply the bait to the tree without contacting the fruit, or a method to attract the female fruit fly that does not require foliage sprays.

“We have tested some alternative baits that are promising, however more work is required to test them on a range of varieties and under different climatic conditions,” Mr O’Farrell said.

The results of the research, which started in July last year, are being analysed and are expected to be released shortly.

The Australian project MT 10250 ‘Farm-wide fruit fly management systems for the east coast of Australia’ is co-funded by the Queensland Government and Horticulture Australia Limited. The project in Indonesian was commissioned by the Australian Centre for International Agricultural Research with co-funding by the Queensland Government. 

For more information, contact Queensland Department of Agriculture, Fisheries and Forestry on 13 25 23.