Tips on buttercup control in grass pastures offered

Posted on Monday, November 4, 2013 at 7:02 pm

NEIL RHODES

u.t. extension

Tired of looking out across your pastures and hay fields and seeing that “sea of yellow” every spring? Unfortunately, many producers in Tennessee are all too familiar with buttercups.

Most of these members of the genus Ranunculus are winter annuals that are easily controlled with a timely application of 2,4-D, and interest in fall applications has increased in Tennessee over the past few years.

Why spray in the fall?

Historically, the vast majority of applications for control of buttercups have been in March to early-April. However, University of Tennessee research and producer experience has continued to show that fall (late October to mid-December) is actually a better time to spray for them.

Why is that? Buttercups emerge in the fall and they are small and actively growing then. As we have discussed numerous times, one of the most important keys to getting good results is to spray buttercups before they bloom. This is an automatic with fall applications, given that buttercups generally do not bloom until spring. Also, oftentimes in the late-winter to spring it is very wet and windy, making it difficult to spray before they are in bloom.

Another reason for fall spraying is that many producers may have more available time then, compared to the spring. Time consuming late-winter to early-spring activities such as calving, spreading fertilizer and getting ground ready for row crop planting often make it difficult to get pastures and hay fields sprayed on a timely basis. Last, but certainly not least, fewer vegetable crops, gardens and active greenhouses are present then; this means the risk of off-target damage to sensitive plants is lower.

In most cases, 2,4-D ester at 1 qt/ provides excellent control of annual buttercups in the fall. The same rules apply as with spring applications. Favorable weather (3 days of day time highs of 60 F); plenty of water (at least 20 gallons per acre spray volume); and the addition of a good, nonionic surfactant (1 qt/100 gallons of spray mix) are all important ingredients in success.

An added bonus for the fall spray program is that it is also a very good time of the year to control musk thistle, buckhorn plantain and wild turnip. These are controlled by 2,4-D and are often present in the same fields alongside buttercups. If buckhorn plantain is severe, consider increasing the rate of 2,4-D.  Keep in mind that 2,4-D, unlike some of our newer pasture herbicides (ForeFront HL, GrazonNext HL, etc.), breaks down relatively quickly in soil. A benefit of this is that with fall applications of 2,4-D, clovers can be planted the following February.

Always remember to thoroughly read the herbicide label before application and follow all directions and precautions.

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