Insecticide combo for canola pests

Exirel insecticide in combination with Parachute spray oil is providing canola growers with an agronomic package to control key insect pests.

Diamondback moth, Helicoverpa and a range of aphids are common pests in canola cause economic damage under a range of conditions.

FMC product development manager Geoff Cornwell said the company released Exirel insecticide as a new mode of action for the control of caterpillar pests and suppression of aphids.

He said it has a number of technical features that make it a robust performer in the field. “These features include the potency of the active ingredient. We're applying fairly low doses of the chemistry to the crop but because the insects are very susceptible to that active ingredient, those rates control the pest well.

“The active ingredient also has ovi-larvicidal activity, which means, for example, if you have a Helicoverpa egg on the crop and the larvae chew out of the egg and there's active ingredient on the eggshell, then the larvae will be controlled.”

The trials also showed good efficacy when combined with the paraffinic spray oil, Parachute.

Mr Cornwell said FMC has conducted field trials with Exirel and Parachute which have shown that it performs well in a tank-mix with Parachute.

“Parachute is also registered as an insecticide for certain species of insects. For example, a rate of one to two litres per hectare of Parachute will give suppression of green peach aphid and native budworm.

“Parachute is a hyper-spreading oil. If you use Parachute in combination with Exirel, you're optimising the spreadability of the active ingredient across the crop. It's going to help drive the active ingredient into the leaf material of the crop.

“The way that diamondback moth feed, they're often on the underside of the leaf and by using Exirel, in combination with Parachute, we’re optimising the coverage of the product on the crop and we’re also getting the active ingredient into the leaf material, which aids in it effectiveness. This technical feature also ensures rainfastness.”

Mr Cornwell said monitoring was particularly important in a canola crop to understand when pests, such as diamondback moth, will cause economic damage.

He said there were certain parts of Australia where diamondback moth tends to be more of an issue. “Areas like the northern and central wheatbelt in Western Australia and also the Eyre Peninsula of South Australia seem to be hotspots for diamondback moth.

“It's important to start monitoring for the pest from July or when the crop is undergoing stem elongation. The Diamondback moth will really flourish in those environments where it's drier and hotter and the pest populations will develop quite rapidly.

“There's a lot of environmental factors that impact on the development of the diamondback moth in the crop. The industry has developed a range of economic spray thresholds, which are a good guide that agronomists can follow to help make decisions on whether to spray.

“The key in using products like Exirel plus Parachute is to focus on ‘best management practice’ for application. When you're targeting diamondback moth in a canola crop, you're going to have a range of instar stages, because you're looking to spray on an economic spray threshold.

Mr Cornwell said while Exirel controls a range of instar stages, it performs best when growers target the earlier stages.

He said getting good spray coverage is important and Exirel plus Parachute can be applied by air or by ground rig.

“For aerial application for Exirel, we recommend a minimum of 30 litres of water per hectare and by ground rig, the label recommends a minimum of 100 litres per hectare to achieve good coverage in the crop to control the pests."

Exirel is considered to have a low to moderate and Parachute a low impact on a range of beneficial insects that occur in canola and have a role to play in reducing aphid numbers.

“We're working in combination with nature,” Mr Cornwell said. “We're using the insecticidal properties of both the Exirel and the Parachute and then the presence of the beneficial insects in the crop like hoverfly larvae, parasitoid wasps and lacewings to try and keep a cap on the development of the aphid population.”

Mr Cornwell said Exirel and Parachute were excellent options in situations where caterpillar pests needed to be controlled, and there was also an early developing aphid population.

He said FMC has a big focus on the stewardship and sustainability of its products.

“It's really important to take into account the big picture, and the future, of crop production.

“Moving forward, the industry must focus on this approach of using products where we can strategically apply them and control the pest, so that the pest populations are below levels that cause economic damage. It's also a way of reducing chemical residues in the commodity and it's also important for resistance management.”

“We have to work smarter in managing these pests and I think a combination of Exirel and Parachute, in conjunction with the beneficial insects that do inhabit canola, is a good way to go."

Source: FMC Australia

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