Soybean School West: Brown Spot, Downy Mildew & Herbicide Injury — Which is Which?

Bacterial blight can cause shredding of the leaves
Can you tell herbicide injury from tan spot? (Hint: flip the leaves)

Can you tell herbicide injury from tan spot? (If only you could flip the leaves)

Soybean growers in Manitoba are — so far — rather lucky. While there are diseases in the province that infect soybeans, like downy mildew, white mold (sclerotinia) and brown spot, overall pressure is relatively low. That will change over time, however, as Vikram Bisht, plant pathologist with Manitoba Agriculture, Food and Rural Development, points out, which means scouting and properly identifying diseases on the soybean crop now is still worth your time, even if a fungicide application is not.

Early infection of downy mildew shows pale green spots on the upper side of the leaves

Early infection of downy mildew shows pale green spots on the upper side of the leaves

Related: Take a look at the insect and disease scouting calendar for Western Canadian soybeans

When it comes to soybeans, there are several leaf diseases of concern. The tricky part is that herbicide injury can also look alarmingly like one of them, plus one disease is caused by a bacteria, rendering fungicides useless. In this Soybean School West episode, Bisht shows us the difference between brown spot and herbicide injury, what downy mildew looks like early on and highlights the tell-tale signs of bacterial blight.

I

Audio-only:

 

RealAgriculture Agronomy Team

A team effort of RealAgriculture videographers and editorial staff to make sure that you have the latest in agronomy information for your farm.

Trending

Wheat prices jump into August — This week in the grain markets

This week, winter wheat prices touched a three-year high, but it didn’t last. Chicago SRW wheat prices for September 2018 gained 5 per cent or about 26 cents US/bushel to close at $5.56. While the December 2018 contract was up 5.4 percent — or nearly 30 cents — to finish a tad under $5.80. In…Read more »

Related

Leave a Reply

 

This site uses Akismet to reduce spam. Learn how your comment data is processed.