Wheat Pete's Word, July 19: White mold, rust, and a wonderful wheat crop!


A harvest update — yes, combines have started rolling in parts of Ontario — as RealAg agronomist Peter Johnson expresses his excitement for harvest in this week’s Word.

There are also concerns about white mold, western bean cutworm, and aphids, to discuss.

Learn about these issues, and much more, in this week’s episode of Wheat Pete’s Word!

Your questions and feedback are needed! Leave Peter a message at 1-888-746-3311, send him a tweet (@wheatpete), or email him at [email protected].


  • First off… yes, wheat! The wonderful crop! Yields are awesome. Okay – not quite as awesome as last year in the province of Ontario but they are still generally above average. The quality has been excellent, test weights just borderline. So that’s one to really note and standability of course not so great. So on that note… yields: the highest yield so far I’ve heard is a 140 – that’s awesome! But many yields in that kind of 80-110 bu/acre range. They’re solid, but not last year’s bin busters.
  • All you in Western Canada are starting to talk about this haze that is coming from the BC forest fires, the wild fires — which is a horrible situation by the way ! Nonetheless, all that smoke is going to interfere with the sunlight that is getting down to the crop. I know a few people that are thinking wow — all that added carbon dioxide in the atmosphere, we’re going to see awesome crop yields. Yeah, I don’t think so, not so much. You get into that haze, and you don’t get photosynthetic efficiency that you want, and that is actually a negative on yield. We need that sunshine!
  • The quality parameters in wheat in Ontario… so far look like fusarium levels, toxin levels, are all very low. That’s a good news scenario. And proteins are looking to be reasonably solid, not amazing, just kind of average. Everything is good with that wheat crop.
  • It’s a white mold year —there are mushrooms everywhere! It probably means we’ve got a lot of white mold sclerotinia that are fruiting, and of course the soybean and the edible bean crop are just at prime time for infection, or at least the early edibles are there. By the way, on white mold on soybeans, we have to spray at least twice, once will not do the trick. If you are going to come back and spray that second time, you need to use a different fungicide the second time. However that goes together for you, resistance management has to be a part of the program.
  • We are seeing all sorts of rust starting to develop in the corn crop. And as a wheat guy, if anybody mentions rust, the alarm bells start going off and everybody saying “Johnson, why aren’t alert alert alert?!” Well, it’s rust in corn. It’s not as big a deal, most of the time. So common rust, you do need to identify. Do you have common or southern? Most of the rust in Ontario is going to be common rust. We have great genetic tolerance in most of our corn hybrids, and so the chances of needing to spray fungicide to control common rust in corn is pretty minimal. Check with your seed supplier. Make sure that you do have a variety that has good resistance to rust. But rarely will we see an economic response to control rust in field corn in Ontario.
  • Southern rust does have more yield impact. So identify the rust that you have. Southern rust lesions are rounder, smaller, more reddish. They are fairly uniform across the upper surface of the leaf, and are almost never on the lower surface of the leaf. You also see them on the stem and on the husk. If you have southern rust, then best to talk to a pathologist about thresholds and all those other things. It’s certainly of more concern.
  • Twitter is just alive with the egg masses of western bean cutworm. We are finding tonnes of egg masses. Don’t forget – you need the tassle to be there. You need to be over threshold, so scout! But if the hassle is not in the whirl, if you are three leaves away, western bean cutworm can lay all the eggs at once, no damage.
  • Aphids in Western Canada….so the threshold is pretty standard across most of North America. Around that 15 aphids per stem at head timing is the threshold. So if you are less than 15, I don’t think it’s worth driving through the crop.
  • We are starting to see soybean aphids showing up in the province of Ontario. Again, you just gotta get out there and scout. We’re at the critical timing. 250 aphids per plant, and rapidly increasing! If you are seeing that – and we are starting to get reports particularly in that central Ontario area of aphid numbers ratcheting it up – then make sure you are on top of that spray. You need to control them!

Listen to previous episodes of the Word here.

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