It's a bug's life in Carnarvon

Kate MatthewsCountryman

An army of minute pirate bugs has come to the rescue of vegetable growers in Carnarvon in a battle against pests and resistance problems.

In the last few seasons, capsicum and eggplant grower Jorge Mendeshas been using predatory bugs bred in Muchea to help increase yields. Before using the bugs, Mr Mendes said he spent a lot of time spraying, a job he was not fond of.

"I hate spraying, so if I can get something to do that job for me, for the same cost or less, it's better," he said.

Growers have been using predatory bugs in Carnarvon for a decade, starting with bananas and citrus, against aphids, caterpillar pests and scale.

But it's only been in the last few years that predatory bugs have been used in other crops where pest pressure is high - mostly in capsicum and eggplant crops.

Carnarvon Growers Association agronomist Adam Kirk and Landmark agronomist Steve Poole estimated that out of 200 growers, as many as 20 were using predatory bugs.

They say growers are trying to find a happy medium using chemicals in combination with the bugs, which allows growers to focus on other issues such as fungal disease.

Also helping the use of predatory bugs is new insecticide chemistry that is more selective and softer on beneficials.

Leading the push for use of the predatory bugs is Manchil IPM Services managing director Lachlan Chilman.

Mr Chilman, who supplies growers across Australia, including Carnarvon, said the benefits included increased yields, less chemical dependency, less spraying and fewer resistance issues.

"It's also a lot safer for workers and they are not going to be killing the natural beneficials that are in Carnarvon but haven't been able to work because they have been sprayed so much in the last two decades," he said.

The main predatory bugs bred at the insectary are orius, the pirate bug to control western flower thrip, persimilis, to control two-spotted mite, aphidius, to control aphids, and cucumeris, to control thrip larvae and broad mite.

In capsicums, Mr Chilman said growers used all four predatory bugs and did not have to do much spraying.

"Once the system starts working it's very easy … first we started working with growers to control mites using persimilis and gradually each season we have introduced another predator for another pest," he said.

The predatory bugs are introduced five to six weeks after planting, at fruit set and followed up by top-up releases.

Seasonal crops need to be recolonised each year.

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