Manitoba farmers have emergency approval to use Carbine against lygus bug infestations in confection sunflowers.
The Manitoba Crop Alliance noted the allowance in a press release July 28.
“The need for an emergency use registration was identified in the wake of the re-evaluation of lambda-cyhalothrin product use in Canada, which left a void in lygus bug control in confection sunflowers,” the farm groups said in the release.
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“This insect pest is a serious economic threat to human consumption market confection sunflowers.”
The 2021 federal decision to ban lambda-cy on certain crops, including sunflowers and any grains bound for livestock feed came into effect this spring.
Carbine is a recently introduced selective pesticide meant to combat aphids in pulse crops, but it has also been shown to be effective against lygus bugs.
“Carbine was chosen because it’s a more selective product and it’s easier on bees and natural enemies,” said Manitoba Agriculture entomologist John Gavloski.
The pesticide will kill some sap-feeding insects. It will not kill chewing insect pests of sunflower seeds, such as banded sunflower moths or larvae of seed weevils.
Lygus bugs feed on developing sunflower seeds, which can cause a physical scar on the bare seed, according to the Manitoba Crop Alliance. Typically, a kernel will have only one spot, on the blunt or distal end, but will take on a bitter taste.
According to Manitoba Agriculture, lygus bugs are capable of damaging 30 to 35 seeds per head per adult.
Because the damage noticeably changes the taste of the seed, sunflower processors have strict regulations that allow only 0.5 per cent damage in their physical product. With those exacting standards, the economic threshold for lygus bugs on sunflowers is low, about one bug per nine heads.
In research trials, damage to sunflower heads was approximately twice as severe when infestations occurred at late bud and early bloom stages compared to stages when heads were fully flowered. This means lygus bug management should be started prior to or at the beginning of blooming.
Farmers are also urged to monitor until flowering is completed to reduce the incidence of kernel brown spot damage.
Lygus bugs have been noted in recent provincial crop pest updates. Manitoba Agriculture has noted an increase in levels in canola plants in the Austin area, but Gavloski says the reason for the emergency use registration of Carbine wasn’t out of any immediate concern of a widespread infestation in sunflowers. It’s just a precaution.
“We just needed something to be used on confectionary sunflowers should an economic outbreak of lygus bugs occur,” he said.
