The Mid-Atlantic outlook

Darin Bevard, director of the Mid-Atlantic Green Section for the USGA. He talks about dealing with goosegrass this season on northern courses.

What are the major weed pressures in the region right now?

Right now, the focus is on pre-emerge applications to control summer annual grasses such as crabgrass and goosegrass. In the southern part of the mid-Atlantic, many have applied preemergence herbicides already, and northern courses will soon follow suit. Some have delayed or skipped preemergence applications because of winterkill concerns, but overall winterkill of areas typically treated with preemergence herbicides appears to be minimal. Broadleaf weeds such as clover and dandelion are developing as well, and it won’t be long until control applications for these weeds go out as well. On bermudagrass, breakthrough of Poa annua and other winter weeds is a bit ugly as cold temperatures have slowed bermudagrass green-up, but winter weeds are growing fairly aggressively.

How is weather affecting the Mid-Atlantic region this month?

The warm weather was very welcome. It accelerated turf growth which has helped with recovery from putting green aeration that many have performed in recent weeks. There is also more of a sense of urgency to begin grooming surfaces for play. Once the weather warms-up and the grass starts to grow, golfer expectations also start to grow! As for weeds, those that haven’t applied preemergence herbicides know that they will need to do so very quickly.

What does the goosegrass pressure look like this year?

We have no way of knowing what pressure from goosegrass will be, but it does seem to be a weed problem that is on the rise in recent years. Goosegrass has proven to be challenging to control post emergently, although some new herbicides have provided better options in recent years.

What are some of the factors that could affect goosegrass growth right now?

Right now, it is all about temperature. Once soil temperatures warm enough to promote germination, it will germinate. Heavy rainfall throughout the spring can shorten preemergence residual. Constant rainfall also keeps soil moisture high which may promote more goosegrass germination.

What can superintendents do to keep ahead of it this year?

Preemergence herbicides are probably the best option. If you know that you have a severe goosegrass problem, oxadiazon (Ronstar) or indaziflam (Specticle) are preemergence herbicides with very good activity on goosegrass. However, indaziflam is only safe on warm season grasses, and cool season grasses can be sensitive to oxadiazon so it is very important to read all label warnings and recommendations when using these or any herbicide. The label is more than just rates. It discusses turfgrass tolerance and application guidelines as it relates to soil moisture, temperature, etc. Also remember that split applications at lower rates may provide better control than a single, high rate application.

What should superintendents do if it starts showing up?

Post emergence applications are really the only option. Once you realize that goosegrass has broken through your preemergence barrier or is emerging in untreated areas, post emergence applications should begin. Goosegrass, like most weeds, is easier to control when it is small. Superintendents also need to realize that goosegrass will germinate on virtually a season long basis all the way until the first frost. Thus, you may feel like you have good control in the early to mid-season, but goosegrass starts to emerge in August. At this point, depending on the weather and the grass species that you are dealing with, post emergence applications could be more detrimental to the desirable grass than the goosegrass. Sometimes tolerating the weeds may be necessary until environmental conditions are such that post emergence applications are safe.