Turfgrass Scouting Report: May 20, 2018

The golf season is starting to gain stride in much of Illinois and many folks are starting to get into a more routine management pattern. Many courses are greening up nicely and the colder weather is finally starting to appear in the rear-view mirror. However the month of May continues to throw curve balls at superintendents and turf managers across much of the region. The dry conditions during early May have given way to thunderstorms and heavy rains events. Some of these severe storms even produced hail in select areas across Chicagoland.

Hail covering a putting green following a storm on May 9th. Courtesy. J. Langell.

Weather

Many courses received large rainfall totals over the past two weeks. Select areas of Chicagoland have received more than six inches of rain so far this month, which is nearly two inches more than the 30-year average for the month of May.

Heavy down pours occurred across the state with some events producing more than an inch of rain in 30 minutes. Needless to say this caused for some flooding issues and standing water on golf courses. These events in-turn delayed agronomic practices and many places have been playing a bit of catch-up mowing roughs or making pesticide applications. The upcoming week should provide dryer conditions heading into Memorial Day weekend, where we could see our next chance of rain.

Seven day loop of total precipitation in the area close to fourinches in some spots when the storms finally exited Illinois.

Disease

The end of this week did provide a few good days to catch up on mowing and spray applications. The large amount of rainfall and warmer temperatures allowed us to see our first symptoms of dollar spot this year.

Dollar spot symptoms on creeping bentgrass in the southern Chicago suburbs.

I would expect to see more reports of dollar spot activity into next week and preventative fungicide applications will be on the radar for many clubs in the area. Hopefully, those that have made early-season dollar spot applications have yet to see dollar spot activity. Additionally, we have received other reports indicating that bipolaris leaf spot, brown ring patch, and anthracnose have also been active in the region.

There are numerous fungicides which provide dollar spot control. However, not all fungicides that control dollar spot can extend activity against the other aforementioned diseases. To help aid in the decision making process, the University of Wisconsin has developed a mobile friendly database which allows the user to see which fungicides can control or suppress various diseases.

Much of the information ingested into this system is from the excellent publication produced by the University of Kentucky and Rutgers University entitled ‘Chemical Control of Turfgrass Diseases’. This database is great for turf diseases especially this time of year where multiple diseases can affect our cool-season turf. The link can be found here (https://turfpests.wisc.edu/) The database also has information on insects and weeds.

Insects

Cutworm activity has been evident within the past 2–3 weeks in the SW suburbs of Chicago. These critters come up to the surface at night to feed and return underground during the day.

Finding pinholes in low cut turf is a symptom that cutworms could be present. Often times if you search in the immediate area you can find cutworms about an inch in the soil. Cutworms feed on the most common cool-season turfgrass species, such as creeping bentgrass and annual bluegrass.

Cutworm damage and hole found on a creeping bentgrass putting surface. Courtesy. J. Benelli.

Damaged turf especially on putting greens can reduce uniformity and smoothness and may disrupt ball roll. Bird damage can also occur in areas where cutworms are present due to the birds pecking into the turf in order to find the cutworms. Insecticides are available to control cutworms in order to reduce the damage they cause on low cut turfgrass.

Cutworm found an inch underground during the day in a putting green. Courtesy. J. Benelli.

To our west, crane fly larvae have also been documented in recent weeks. It is unclear how much damage they could bring in Illinois. Still, it may be important to monitor their presence moving forward.

Weeds

Dandelions found in western Chicago suburbs.

Dandelions seem to be causing a headache this year, either due to the weather or the inability to make applications because the ground is too wet for a sprayer. If dandelions and other broadleaf weeds are still lingering around, herbicides with amine formulations are the best options for control now. According to the GDD tracker from Michigan State University courses closer to the lake can still use ester formulations, however time is running out.

Ester/Amine Spring Broadleaf Herbicide Timer.

Annual bluegrass seedheads are very prominent right now, especially in rough areas. Unfortunately there’s nothing that can be done at this point if Poa is seeding on playing surfaces. Using brushes or groomers on mowers can help to dislodge seedheads which then can be removed from the playing surface. However this is easier said than done and will not eliminate all seedheads entirely. The good news though, the end is almost in sight for Poa seedheads to stop flushing as parts of central Illinois south of I-70 should be done sometime this upcoming week.

Annual bluegrass seedheads flushing in the rough in the western Chicago suburbs.

Another grassy weed to monitor right now is crabgrass and goosegrass. Those with a prior history of these weeds should scout carefully for their emergence. Crabgrass has already germinated in many areas with south facing slopes or in areas next to cart paths. As soil temps continue to rise, the emergence of goosegrass will likely begin germinating in the near future.

These grassy weeds are becoming more problematic on closely mown fairway surfaces (<0.400”). Post emergence control gets exponentially more difficult as these plants begin to mature. The use of HPPD inhibiting herbicides (while expensive) can help provide post-emergent control of these weeds.