USGA: Mid-Atlantic UPDATE

USGA: Mid-Atlantic

WHY CAN’T WE KILL THESE WEEDS?

By Elliott L. Dowling, agronomist, Mid-Atlantic Region
July 23, 2014

Weed control in summer is difficult with weeds turning off-color following herbicide
applications, but often still able to recover.   Sequential applications at low rates are
the best method for control, especially during the hottest months of the year.

If weed populations seem out of control on your golf course, you are not alone. Broadleaf and annual weeds have emerged on golf facilities throughout the Mid-Atlantic region. Weeds such as kyllinga, yellow and purple nutsedge, goosegrass and crabgrass are widespread. Unfortunately, they can be very difficult to control during summer due to the potential risk of injury to desirable turf.

Postemergence applications should have already begun. Generally, better control is realized while the weeds are small. Keep in mind that during hot and dry weather weeds have reduced ability to absorb herbicides which equates to reduced control. If you are currently in a dry period, delay control applications until adequate soil moisture is present.

Careful herbicide applications must be made on cool-season turf, especially in midsummer heat. Sequential, low-rate herbicide applications are often the best method for postemergence control, especially on sensitive grasses such as creeping bentgrass. If control measures are not implemented in a timely fashion, populations will continue to increase.

Source: Elliott L. Dowling (edowling@usga.org)