Goose on the Loose

This summer, we have seen a dramatic uptick in the amount of Goosegrass on the golf course, particularly in the primary rough.  The white appearance of Goosegrass treated with a post-emergent herbicide, may grab your attention more than an untreated plant.

There are a few possible explanations for the increase we're seeing with this weed:

• Early drought--If you think back to June, much of the turf was dormant due to high heat and lack of rainfall.  There is an old saying that a dense, healthy stand of turf is the best defense against weed encroachment.  With the turf being dormant, this may have allowed for more Goosegrass to germinate and become established.
• Lack of Uniform Coverage--We make our pre-emergent herbicide application in late fall, to prevent grassy weeds such as Crabgrass and Goosegrass.  The last two years, we have switched from using a granular product applied with a spreader, to a liquid product applied with a sprayer.  The active ingredient in both formulations is the same, however it can be more challenging to achieve complete uniform coverage in the contoured rough with a boom sprayer than it is with the tractor mounted spreader. 
• Herbicide Resistance--This may be the most probable cause of the issue, and it is also the most concerning. As this snippet from Rutgers points out, Goosegrass is known for this:

Going forward there are a few changes we will be making.  This will likely include returning to a spreadable product, as well as possibly changing the active ingredient used as a preventative herbicide.  Should these measures fail to prevent Goosegrass germination, we will be quick on the trigger to treat the weed with an effective post-emergent product.