Wheat Pete's Word, Sept 6: How to combat your perennial weed problem


Will late rain do much to help soybean yields? Is it okay to clip clover once more? When should I apply sulphur to a winter wheat crop? What impact are cold nights having on corn crops? And, what to do about perennial weeds?

In this episode of The Word, RealAg’s resident agronomist Peter Johnson fills us in on the latest fall issues.

Have a question you’d like Peter to address? Or some yield results to send in? Leave Peter a message at 1-888-746-3311, send him a tweet (@wheatpete), or email him at [email protected].

Though we recommend taking the time to listen to the entire show, you can also pick out the topics that most interest you, by using the summary below as a guide.


01:00 – Yields coming in big…where there’s moisture.

02:00 – What about the cold? Corn’s an interesting crop, and if you go below 9ºC, you lose a day. Corn needs roughly 60 days, frost-free, between pollination and really good test weight corn. Scarier, when it goes below 4°C, then you lose two or three days in that 60 day period. When we lose those days, it takes more kernels to make a bushel. Earlier hybrids on a year like this would be better, but this year is a bit of an anomaly.

06:15 – Double cobs on corn plants means population may be a bit on the low side, but otherwise, the corn is really, really happy. More yield.

06:40 – Soybeans – By R6, most of the yield hit has already happened. Late rains may increase seed size slightly, but realistically, soybean yield is all about pods — the more pods, the more yield.

07:50 – What is with all the weeds in the wheat stubble?

09:00 – Would clipping stubble with clover in it help the clover? If I wrap clover for feed, what are the root-growth impacts? What if it has 20-30% blooms again already? Does clover give you biodiversity in my wheat, because I have fewer stripe rust problems?

11:30 – Greenfeed oats with alfalfa – oat regrowth polluted with rust. This isn’t just a 2017 issue. Grow a resistant oat variety like Bullet.

12:15 – There is not much of a boost to sulphur applied to wheat in fall in Ontario.

12:40 – Winter wheat in fall 2016, and European chafers wiped it out. Use an insecticide seed treatment to help.

13:20 – Winter barley vs winter wheat.

14:00 – Perennial weed control is best in the fall. The key, for perennial sow thistle, is to having a big enough rosette (9 leaves). Glyphosate works until -4°C at night. For Canadian thistle, you get the best control after the first -2 to -3°C frost (that’s when it starts to translocate everything to roots). Try Estaprop or MCPA. Get yourself a copy of the Problem Weed Guide for Ontario Crops.

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