Playing Detective Puts More Bushels in Your Bin

As the soybean crop comes off across Ontario many growers are seeing bin-busting results despite the challenging start to the season.

“It's amazing how well the crops turned around,” says Shawn Brenneman, agronomic sales representative for Syngenta. Like other parts of the province, his Middlesex/Elgin/Lambton territory was dry for much of May and June – even into July. “The rains in July and August really helped those beans set the right amount of pods, and we're seeing a lot of three-bean and four-bean pods this year ­– more than normal.”

The reality is, however, there will be some fields that don’t do as well as others. It’s those areas that growers need to note for future seasons.

“At the end of the day, we want the whole field to yield well,” says Brenneman. “As you're harvesting, be aware of areas of the field that just didn't perform as well as you'd hoped or expected. Do a little detective work and ask yourself: ‘What happened that limited my yield here in this spot?’”

Determine disease challenges

With the considerable moisture that crops received in August, diseases like sudden death syndrome (SDS), white mould and Phytophora are all potential culprits. Fortunately, strategic variety selection and quality seed treatment will help ensure that those diseases won’t steal yield from future bean crops.

“We are seeing fields that have never been affected by SDS before showing symptoms now,” says Brenneman. “I tell growers it's likely a combination of environmental weather conditions and soybean cyst nematode (SCN).”

He explains that SCN infects the roots and opens the plant up to secondary diseases like SDS. “I always recommend to growers, especially if you've got a patch in the field that's showing high SDS, go test that spot for SCN,” he says. “That’s one way for growers to understand their risk for SCN and to mitigate SDS in future years.”

Brenneman also expects some growers will be seeing signs of Phytopthora. “It’s is a water-loving disease that can take plants out at any stage of development,” he says. “So, with all that August rain we are seeing some low spots where water was ponding. Phytophora has come in and basically killed the plants.”

White mould is showing up in some areas, too. “I expect this year is going to be significantly less, but there will still be some white mould issues that could be a management concern going forward. Because white mould sclerotia survives for several years, growers need to remember that the next time they go back into soybeans in that field, the risk is going to be higher,” says Brenneman. “If you do see significant white mould this year, just make sure you're selecting varieties that have great white mould tolerance for future years.”

Frog eye leaf spot is another disease that has been popping up. “It's not usually a disease we see a lot of,” says Brenneman, adding that the weather created ideal leaf disease conditions. He explains that it won’t likely cause significant yield loss but suggests growers should take note if they’ve got a variety that is highly affected.

Brenneman believes growers who applied foliar fungicides this year will see a benefit. “Those plants have gone through a lot, whether it be drought stress or later-season water stress. I think we'll see fungicides pay off well from a leaf disease perspective and overall plant health.”

Evaluate weed control

Harvest is also a great time to evaluate how your weed control program fared. As he traveled the countryside, Brenneman observed that full pre-emerge programs stood out this season. “They really look strong,” he says. “Early on, a lot of beans under drought stress struggle to close row. So those full pre-programs held enough to be able to allow those canopies to develop and then shade out more weeds later on.”

Make harvest notes

Whether you’re done taking off the crop or if your combine is still rolling, keep in mind those areas in the field where yield drops off significantly and you're not sure why. Think back on the season – did you see issues that Brenneman has highlighted? “In some cases we are talking 10 to 50 percent yield loss in those specific areas where these pests and diseases are a problem,” he says. After your harvest investigation is complete, be sure to record some notes to help you capture the full potential of your soybeans in future seasons.