Pylex treatment on 4 approach

The evidence of chemical treatment has rarely been as clear as it is on #4 approach over the last week. Small and medium splotches of bright white turf mixed in with the green has made for a very different appearance. It is unsightly, but it is not without reason. Each spot contained a weed called goose grass. It is a weed that appears at a similar time to crabgrass and can be equally as difficult to manage.

#4 approach was especially hard hit by Spring Dead Spot (SDS). The reason or reasons that this particular area was more severely affected than other areas is only conjecture. What we do know, though, is that because of the severe disease infection, it allowed bare areas to be infested with goose grass. The Bermuda grass is very slow to heal across the patches and the opportunistic weed pounces. Similar to other areas of the course, there was some less than desirable pre-emergent weed control on this spot also. When combined with the disease-weakened Bermuda grass, it was only a matter of time before the weeds filled in the voids.

In years past, goose grass was very difficult to control chemically. The most effective defense was pre-emergent control. Once that was defeated, hand-picking the weeds was the most effective tactic; but for this situation, there were too many small plants to hand pick efficiently. Recently, a new herbicide has been developed that does a tremendous job controlling goose grass. However, it is also tremendous at injuring Bermuda grass. This is why #4 approach is dotted with white spots. The herbicide works by disrupting carotenoid biosynthesis, which directly affects photosynthesis. Treated plants slowly turn white as chlorophyll is depleted, and the weeds can no longer produce food causing them to die.

The treated spots are easily visible. However, imagine if everything within the black lines was as white as the spots from a broadcast spray. Spot treating was the best option in this case.

We spot sprayed #4 approach with this new chemical and were very diligent to spray as little as possible on any Bermuda grass. Goose grass was intermixed directly into the Bermuda grass so we were unable to keep the herbicide off the Bermuda 100%; however, we were far more successful than if we had done a broadcast spray across the entire approach. We were willing to tolerate some injury to the desirable turf in order to treat the weed issue.

The good news is that Bermuda grass is extremely resilient and will only be injured by the herbicide not killed. The extensive root system of the Bermuda grass allows some of its leaves to be affected but also allows it to still be able to translocate food to the main growing points of the plant and outgrow the herbicide damage. Over the next couple of weeks the color will return to the Bermuda grass but not to the weeds. They will still be visibly white until they turn brown, shrivel and die.

In related work, we are also plugging new Bermuda grass into other SDS areas in the fairways. By taking unaffected turf from our nursery and introducing it into the bare areas, we hope to establish some viable Bermuda grass.  We cannot 100% control SDS, but healthy Bermuda grass is the first defense, so getting these thin areas to fill in as much as possible before winter is key. We will also continue our other planned SDS control measures. Between the plugs and other means we will continue to reduce the quantity and severity of the Spring Dead Spot issues

Bermuda grass is a tremendous turf for our situation at Bretton Woods. Spring Dead Spot is its one Achilles heel, but between new herbicides and our increasing knowledge for handling and treating for the disease, we continue to try and improve the Bermuda grass conditions at Bretton Woods.

Etiquette Reminder of the Week

Thank you for using the green sand to fill your divots on the course. Please remember to not overfill the divots. A mound of sand will damage our mowers.

See you on the course!

Joe

jvillegas@bwrc.org