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Australia’s avocado growers may be able to significantly increase yields if they encourage a diversity of insects around their orchards, according to new research into the best ways of optimising pollination in the fruit.

The study is being carried out with the help of growers in the tri-state area around the border between South Australia, Victoria and New South Wales. Plant & Food Research Australia is carrying out the research, which is being funded by Horticulture Innovation Australia (HIA).

Lead researcher Brad Howlett said most people assume honey bees are the best pollinators, but with avocados this may not be the case.

“Some of the orchards with the best yields have very few honey bees, but an amazing diversity of flies, and a close study of their ability to transfer pollen shows many are as effective as bees,” Mr Howlett said.

“Avocados are tricky because the flowers not only open as male one day and female the next, but are usually only open a few hours a day – or even open at night if it’s cold.

“That can be problematic if you’re relying on bees, because they aren’t active at night, and don’t like cold or rain.

“The benefit of encouraging populations of various insects during flowering is that each one has a different behaviour, so you have a better chance of them being active at the right times.”

Growers already know that yields can be up to ten times better if flowers are adequately pollinated. Polliniser trees planted amongst the main varieties such as Hass, can improve cross-pollination by providing a source of pollen.

During the next flowering season researchers hope to investigate how the pollen flows between the varieties, as well as continuing more detailed field surveys into the different species of insects in the crops.

Mr Howlett says the findings may mean the avocado growers lucky enough to have an abundances of fly pollinators are probably somewhat protected from the impact of the Varroa mite, a bee pest that’s devastated global honey bee populations and the crops that rely on pollination.

“If flies can do the job just as well and we find them to be widespread, avocados may be one of the few crops that isn’t as adversely affected if Varroa enters Australia and wipes out most of the feral honey bees that many growers rely on as their main source of pollination.”

 

Media contact: Kaaren Latham 02 8204 3852 (Plant & Food Research Australia)

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