Getting the Best Value for Weed Control This Spring | Corn School

Why It Matters

Effective spring weed control preserves yields and profitability while preventing herbicide resistance, crucial as input costs rise and commodity prices fall.

Key Takeaways

• Apply herbicides early when weeds are small for maximum efficacy.
• Avoid cutting rates; low doses increase resistance risk.
• Identify glyphosate‑resistant annual ryegrass and use multiple modes.
• Use adjuvants, crop oils, and tank‑mix partners for tough grasses.
• Time applications on warming, dry days to improve control.

Summary

The Corn School video spotlights spring weed‑control tactics for corn growers, emphasizing precise herbicide placement, timing, and rate selection amid falling crop prices and rising input costs.

Rob Miller explains that many producers skipped fall weed control due to a dry season and weak markets, now facing early‑season pressure from dandelions, shepherd’s purse, and other broadleaf weeds that become harder to kill once they enter reproductive stages. He also flags the rise of glyphosate‑resistant annual ryegrass and expanding bluegrass infestations, urging growers to correctly identify these species and employ multiple modes of action, adjuvants, and appropriate tank‑mix partners.

Key examples include the label‑mandated higher glyphosate rates for dandelions taller than 15 cm, the diagnostic clasping auricles of annual ryegrass, and the recommendation to spray on a warming, dry trend rather than during windy or wet conditions. Miller stresses that proper timing and full‑rate applications reduce the need for repeat passes and curb resistance development.

For producers, adopting these practices safeguards herbicide dollars, maintains field cleanliness, and protects yields in a market where every profit margin counts. By preventing resistance and optimizing control, growers can better navigate volatile commodity prices and tighter cost structures.

Original Description

As growers look to manage weeds in corn this spring, tight margins are putting extra pressure on every herbicide pass.

In this Corn School episode, BASF Canada agronomist Rob Miller says getting the best return on weed control comes down to timing, product choice, and understanding what’s happening in the field. In a year where every input dollar counts, effective weed control isn’t about spending less — it’s about spending smart, using the right products, rates, and timing to protect yield potential.

Miller notes that some growers skipped fall weed control last year due to dry conditions and lower commodity prices, and that decision is now showing up in spring fields. Weeds that have already advanced to reproductive stages — such as dandelion, shepherd’s purse, and Canada fleabane — are tougher to control and often require higher rates.

When it comes to maximizing return on investment, Miller is clear: cutting herbicide rates is not the place to save. Lower rates can reduce efficacy and increase the risk of resistance, especially as weed pressure and diversity continue to grow. Instead, growers should focus on matching products to the weeds present and applying them under the right conditions.

Timing is also key. Applications made during a warming trend, with a few days of favourable weather following, will typically outperform those made ahead of cool, wet conditions.

Miller says annual ryegrass is a growing concern across Ontario, including confirmed glyphosate-resistant populations. He advises treating it more like a perennial than an annual, noting that control becomes especially difficult at the jointing stage. Early intervention when plants are small, along with the use of multiple modes of action, adjuvants, and proper rates, is critical to keeping this weed in check.

Website: https://www.realagriculture.com/

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