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El Niño may Boost Cool-Season Pasture Weeds

El Niño may Boost Cool-Season Pasture Weeds

Ferrell thistle

Thistle and other cool-season weeds could be more numerous in 2016 due to the El Nino, so producers should scout early and spray while weeds are still small.

The summer of 2015 will long be remembered for the consistency and amount of rainfall received. This was a great benefit for the crop farmer, but made life exceedingly difficult for the hay farmer. With all this rain I saw many pastures that were “soggy” all summer. Bahiagrass is a durable and highly persistent grass that can tolerate periodic flooding. But this past summer provided weeks to months of water standing on the pasture, or just below the surface. In this environment, roots begin to die off and the overall vigor of the pasture declines. This will allow open spots to form in the grass and create an ideal environment for weed encroachment.

The weeds I most expect to see are the common winter/spring weeds: thistles, red sorrel, and wild radish/mustard. Though we see these every year, I anticipate that they will be more numerous in 2016. Therefore, I suggest that you scout early and often, and be ready to spray. Generally speaking, spraying small weeds will translate into better control at a lower cost than waiting until the weeds are large, so be ready. There is no reason to bale weedy “cow hay” for the first cutting, when a herbicide application in March could control those weeds. As long as daytime temperatures are 60-65 F (or higher), the herbicides will work fine. At these cooler temperatures, switching to a 2,4-D ester instead of an amine will also provide a positive herbicide benefit.

Ferrell wild radish

Spraying small weeds will translate into better control, at a lower cost than waiting until the weeds are large. This wild radish (aka wild mustard) is easy to control at this size, but very challenging once it starts flowering.

A proactive weed management strategy will allow the pasture to transition from winter dormancy without weed competition. This will provide a good environment for the grass to reestablish itself and improve the first hay cutting.

For specifics on which herbicides fit your particular weed problems, please consult:  Weed Management in Pasture and Rangeland



Author: jferrell – jferrell@ufl.edu


Permanent link to this article: http://okaloosa.ifas.ufl.edu/newsletters/2015/11/21/el-nino-may-boost-cool-season-pasture-weeds/