Wheat School: Think about beneficials when controlling aphids at T3 timing

It’s time for T3 fungicides to control fusarium head blight in Ontario’s winter wheat, but growers may also have another troublemaker in the cereal crop that they’ll need to tackle this time of year.

There have been growing reports of cereal aphids in the Ontario winter wheat crop this spring, and growers need will to keep a sharp eye when scouting and staging wheat fields. On this episode of RealAgriculture’s Wheat school, agronomist Peter Johnson tells growers to be on the lookout for lady bugs (and larvae) when they enter fields. It’s the first sign that you may have aphids in the field.

Johnson notes that the economic thresholds for cereal aphids are 15 aphids per stem prior to heading; and 50 aphids per head at heading. “Get your head down in the canopy and look for those aphids,” says Johnson. If growers find aphids at high enough levels, T3 fungicide timing is a right to combine fusarium and aphid control.

For Johnson, however, the decision to spray for aphids requires some thinking. “If you control the aphids it will help the wheat crop, but be very aware of the thresholds,” he says. “Be aware of the importance of beneficials such as lady bugs and lacewings — they are feeding on the aphids and in the process they are multiplying.”

Could aphids in the wheat crop indicate that soybean aphids may show up later in the season? It’s possible, says Johnson, though the two pests are completely different. But the beneficial insects feed on both types of aphids, and that’s why he’s asking growers to think beyond the wheat crop when opting for aphid control at T3.

“The more wheat fields that we can just let the beneficials take care of the aphids, the better we’re going to do having beneficials available to control all the other pest throughout the year.” (Story continues after the video.)

When scouting, Johnson highly recommends growers consult the Cereal Aphid Manager App to help make aphid control decisions.

When it comes to applying a fungicide at heading — that’s a no-brainer, says Johnson.

He notes that 75 per cent of the time a T3 application gives growers at least enough yield to pay for the fungicide and that doesn’t include the crop quality, standability, and straw quality benefits. “It gives you better quality, controls the fusarium in the crop and keeps the canopy green. It keeps the plant tissue alive longer and that’s what gives us the added yield.

Click here for more Wheat School videos.

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