Fall Weed Control Ahead of Cereals, Not Canola

Nov 03, 2011

Fall Weed Control Ahead of Cereals, Not Canola

The opportunity to spray weeds is nearly closed for this fall, especially on fields planned for canola in 2012. If you have a stretch of warm sunny days in the forecast, you might have a chance to give dandelions one last hit. Note that glyphosate needs a few warm days with several hours per day of bright sunlight as well as non-freezing conditions (day and night) to do its job well. If using residual product, be mindful what you’re seeding next spring. The best product to use at this time of year is 2,4-D, but spraying now ahead of canola won’t give it enough time to break down before seeding next spring. Do not spray 2,4-D on land planned for canola next spring. 2,4-D is suitable to clean up fields for cereals next year.

2,4-D can be applied for winter annual control as long as the nozzles are not freezing up. If you have the space, keep the sprayer in a heated shop overnight and wait until temperatures are above freezing to start spraying. Phenoxy herbicides not only control winter annuals directly by crushing stem tissues and cutting of water supplies, but also by sending a signal to resume growth when they should be entering a dormancy phase to survive the winter.

If your target is narrow-leaved hawk’s-beard, take note: This weed is not susceptible to 2,4-D at this time of year and 2,4-D can actually interfere with hawk’s -beard control next spring with glyphosate. That’s because the injury that 2,4-D causes to the plant actually protects it from the glyphosate.

Source: Canola Council of Canada

Video: Spring 2026 weather outlook for Wisconsin; What an early-arriving El Niño could mean

Northeast Wisconsin is a small corner of the world, but our weather is still affected by what happens across the globe.

That includes in the equatorial Pacific, where changes between El Niño and La Niña play a role in the weather here -- and boy, have there been some abrupt changes as of late.

El Niño and La Niña are the two phases of what is collectively known as the El Niño Southern Oscillation, or ENSO for short. These are the swings back and forth from unusually warm to unusually cold sea surface temperatures in the Pacific Ocean along the equator.

Since this past September, we have been in a weak La Niña, which means water temperatures near the Eastern Pacific equator have been cooler than usual. That's where we're at right now.

Even last fall, the long-term outlook suggested a return to neutral conditions by spring and potentially El Niño conditions by summer.

But there are some signs this may be happening faster than usual, which could accelerate the onset of El Niño.

Over the last few weeks, unusually strong bursts of westerly winds farther west in the Pacific -- where sea surface temperatures are warmer than average -- have been observed. There is a chance that this could accelerate the warming of those eastern Pacific waters and potentially push us into El Niño sooner than usual.

If we do enter El Nino by spring -- which we'll define as the period of March, April and May -- there are some long-term correlations with our weather here in Northeast Wisconsin.

Looking at a map of anomalously warm weather, most of the upper Great Lakes doesn't show a strong correlation, but in general, the northern tiers of the United States do tend to lean to that direction.

The stronger correlation is with precipitation. El Niño conditions in spring have historically come with a higher risk of very dry weather over that time frame, so this will definitely be a transition we'll have to watch closely as we move out of winter.