Utilising softer chemistry options to control pest such as fruit spotting bug has become essential to achieve high yields of quality nuts in Macadamia orchards around Bundaberg, Queensland.

Jonathan McDonald and Kate Piper, from Agronica, look after multiple macadamia orchards in the region advising growers on the best options for pest control.

“We're scouting trees every week to two weeks,” Johnathan said.

“Fruit spotting bug is one of the most damaging pests for the macadamia industry, in regard to both yield and quality.”

He said they looked at softer chemistry, particularly earlier in the season, to keep beneficial insects in the orchards rather than taking them out with broader spectrum products.

“We have seen flare events with spotting bug when we have introduced a more broad-spectrum product. We actually see a rebound in the pest because we’ve controlled spiders and parasitic wasps.”

He said with a softer product they were taking the cap out of the pest population and allowing the beneficials to catch up on that population.

Kate said the scouting involved a cut nut assessment to determine how many have been stung by fruit spotting bug.

It also took into account the number of beneficial insects in the orchards.

“Some of the nuts are a result of premature nut drop or poor pollination but you can get a grasp with how many stung nuts you find and what the pressure is like.”

“We can then pull the spray forward or push it back a week depending on the results.”

She said the first spray for fruit spotting bug was Transform WG Arylex active, from Corteva Agriscience.

“Transform WG targets spotting bug and it’s a soft product on beneficials.

“We do multiple sprays, generally earlier in the season, so we can use our other chemistry at the back end.”

Jonathan said they had conducted their own research comparing products and spray systems at their own farm at Alloway, south of Bundaberg.

“We can conduct a lot of that work on farm and showcase new options for growers to improve their productivity.”

“Last year that included further benchmarking with Transform WG and other products considered softer in the program,” he said.

“We found the beneficial ratios were two to three times higher versus using a conventional spray program with broad spectrum chemistry.”

“The softer programs have generally outperformed the broad-spectrum programs each year giving us a better-quality product.”

“If we’re not maximising premium kernel numbers for growers its going straight off their bottom line. It’s something that comes on a piece of paper at the end of the year which makes you fully aware of how important that quality is.”

He said the spray program was critical in achieving good yields and high quality with product selection and good timing essential elements.

“ It's about timing those sprays on the building population, making sure that we're spraying when there is a pest there, but also just making sure that we haven't gone past thresholds that are higher than the products can handle.

He said drop sheets are used through critical times later in the season.

“Earlier in the season it is easier to find fallen nuts on the ground and do the cut nut assessment of what damage is in the orchard.

“When the nut starts to stick to the tree in the mid-November to early December period the drop sheet monitoring gives us a real indicator on how our early season products have worked when it comes to preserving our predators and beneficials.”

“We're doing our best just to conserve general good biota in the orchards, of good beneficials throughout our programs.

“That starts the season before, where we're giving the trees a breakthrough flowering until those first insecticide sprays.

“We're just trying to conserve the natural predators that are in the area.”

He said one of the reasons Transform WG has fitted into the program has been the support from Corteva over many years.

“Corteva has been excellent for us and our staff understanding the products by conducting field days on farms and allowing us to have a first-hand look at products in the early development phase as well.

“It allowed us to set Transform WG up in the program very easily to help our growers.”

“This is an ever-changing industry. I enjoy working with the team that we've got in at Agronica and also the team at Corteva.

“They’re a great group of people,” Jonathan said.

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Thursday, 9th July 2026

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