Drones trialled in horticulture to release predatory wasps to reduce chemical use

Date:08-04-2020

By Melanie Groves

Drone-loads of predatory wasps descending onto crops of growing vegetables may seem menacing, but the tactic is helping farmers lessen their impact on the Great Barrier Reef.

Parasitic wasps are already in use in small crops around the country as a biological control where they target pest insects such as the silverleaf whitefly, reducing the need for farmers to rely solely on chemicals.

Bowen-based agronomist Jessica Volker said using predator insects in vegetable crops was part of a multi-pronged approach to integrated pest management.

"The wasps are excellent because not only do they help control the pest, they also take the pressure off our chemicals and hopefully reduce resistance to those chemicals," Ms Volker said.

In north Queensland's salad bowl of Bowen, growers and industry are working together to trial drones as a step towards making the practice more labour, cost and time-efficient.

Licensed drone pilot Luke Jurgens is working with the Bowen-Gumlu growers association on a trial to release predatory wasps from a drone into tomato fields.

"Prior to drones, the consultants or agronomists would go through with vials with little wasps inside," Mr Jurgens said.

"They'll go along in a bay of tomatoes, or any crop, and just drop them so many metres apart, where they'd hatch from their vials and do their thing.

"But with a drone, we're taking away from people walking through the field."

Taking to the skies

Mr Jurgens has flown drones for years and has long seen the potential for an industry using them in Bowen.

"I've always believed there was an industry here for it. We're [now] trying to make a business of it," he said.

"[Using drones] is faster, [to spread beneficial insects] and you get a good even spread."

Better coverage of the crops by the insects, while reducing the risk of biosecurity breaches from people walking through paddocks, was part of what Ms Volker saw as the potential benefits of using drones over hand releases.

"The big picture is trying to reduce our chemical usage overall, and reduce the negative impacts chemicals have on the environment and particularly the Great Barrier Reef," she said.

Benefits will spread

Ms Volker hoped that more efficient methods of releasing insects might inspire more growers to get involved, citing the benefits of a community effort to control pests.

"The more growers start releasing beneficial [insects] the further reaching those benefits are," Ms Volker said.

"If you have the larger growers controlling their pests, then there are fewer pests to go to the neighbours and so forth."

While the initial releases were looking to control silverleaf whitefly, Ms Volker also saw a future use for drones to release other beneficial insects.

"That's something we're looking into closely, particularly now that we've got the fall armyworm issue," Ms Volker said.

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