Herbicide resistance is increasing, and that means California tree nut growers must stay vigilant and nimble to keep weeds at bay.
Weeds compete with trees for nutrients, increasing vulnerability to insects, arthropods and disease, ultimately impacting yield. But a comprehensive weed management program can help ensure that pressures don't threaten profits.
The best practices listed below can help growers combat common weed threats, ensuring healthy trees and high yields from year to year.
Understand the Unique Threats to Orchards
Not all weeds are equal. Some require specific conditions to thrive, making certain locations in the orchard and times of year ideal for growth. Growers should monitor regularly, making note of the type of weed, where it grows and the management tactic used so that adjustments can be made, as needed, throughout the year.
Clean Equipment Before Bringing it to the Field
Equipment used in a field threatened by weeds can easily contaminate otherwise healthy fields. Clean all tools of plant parts, mud and dirt to avoid the risk of cross-contamination. The University of California, Davis, recommends harvesting orchards where known herbicide-resistant weeds exist after other areas.
Rotate Herbicides with Different Modes of Action
Weed resistance can occur when using the same type of herbicide repeatedly, a problem many California growers have seen with glyphosate treatments. Utilizing products with different modes of action during the growing season and from year to year can help reduce the development of resistance.
Consider Pre-emergent Sprays for Prevention
Growers should consider attacking weeds before they breach the surface with pre-emergent products such as Alion® herbicide from Bayer. Pre-emergent herbicides enter the root systems of the weeds and kill them before they can germinate, providing a perfect complement to contact herbicides that treat weeds after they emerge. Pre-emergent herbicides also have a different mode of action than glyphosate treatments, reducing the likelihood of developing resistance.
Pay Attention to Label Rates
Experts advise that growers should always adhere to the label rates listed on the products. These rates may vary by soil type, rainfall and other factors.
Learn more about weed management and how a long-lasting, pre-emergent solution like Alion can help keep orchards clean all season long.