Cotton pest management plan inspired by a taste for strawberries

In 2014, he began using an integrated pest management program introduced by his agronomist Steve Madden that applied beneficial parasites to his cotton crop by drone to control pests like silverleaf whitefly.

"I love strawberries, really love them, and when Steve told me about the pest management program, I saw it made sense. I'm in, I told him," Mr Carberry said.

A decade on, Mr Carberry and his family-run operation are growing 700 hectares of irrigated cotton and 100ha of dryland cotton, using an innovative method to apply biodegradable capsules filled with parasitic wasp larvae delivered by aircraft to the fields.

He said the increase of silverleaf whitefly on Emerald cotton farms on Queensland's Central Highlands was impacting on crops well before northern NSW growers' crops.

The cost of chemicals was also a concern as it could impact on populations of beneficial parasites.

"So it became a study of the economics of spray versus capsules," he said.

Mr Carberry said the capsule program, which includes two applications, cost around $70 a hectare.

"So it's roughly the same cost as a chemical application with a better environmental outcome."

The degradable capsules are made from corn starch and vegetable oils and contain a population of 500 parasitic Eretmocerus hayati wasps equally split between males and females used for silverleaf whitefly control.

Mr Carberry said careful monitoring for silverleaf whiteflies determined when the crop capsules were applied by aeroplane at a rate of two to a hectare.

He said checks by the agronomists close to the first flower on the cotton plant would often reveal adults and nymphs on the underside of leaves.

The application of CottonCAP capsules occurred at this early stage in the infestation cycle, before heavier whitefly egg lays and nymph clusters appeared.

"You've got to have some population for the emerging parasites to feed off, and then they can continue to spread their eggs and add to the control process," he said.

Capsules protect parasitic wasps during application and emergence over five days and provide a convenient, safe and productive environment for mating, Mr Carberry added.

Rain in the past two weeks has also put the use of beneficial parasites into a sharper perspective.

"We had between 120mm and 150mm in the first week of January and more storms with another 10mm to 20mm last week.

"If we'd applied chemicals before that rain, its impact would have been significantly reduced, but the parasite (wasps) will keep breeding and attacking the whitefly.

"We try and get the capsules out as soon as there is evidence of a whitefly population to support them."

He said the first application of the capsules on his cotton crops was in 2019.