Turfgrass Scouting Report: July 1, 2018
June has finally come to an end and I think everyone is glad to see it leave. This past month has been a challenge maintaining turfgrass and with many courses hosting upcoming tournaments, July may be difficult. Two record setting months of rainfall totals have been a major story line so far, followed by oppressive heat, many courses are seeing pest issues almost a month earlier than normal. Superintendents are on high alert following this period of weather for declining turf. Sprayers were busy this week making sure that every part of the plant is covered ahead of this heat. These applications were critical to make sure that some of our nastier pathogens do not have a chance to cause headaches down the line and the rest of this summer. Hopefully July will return to a normal weather pattern, but until then let’s take a look at some of the high points and low points from the past two weeks.
As I mentioned earlier record setting rainfall totals were set in May and again in June for parts of Illinois. Areas around Rockford saw the most rainfall in a single month since 1905. Compared to the average, Rockford was nearly 10" above normal. The Chicagoland area on average courses saw about 8" of rain and even more in some locations. Again this is well above normal and nearly 5" above normal for Chicago. Further south, in central Illinois, many courses are above average for rainfall totals but only by 2" or 3". Needless to say, everyone has been wet and cloud cover has been an issue across the state and region.
Friday and Saturday were extremely hot and some of the peak heat index measurements across the region parts of Chicagoland were above 110°F. While looking through twitter Thursday and Friday afternoon a reoccurring theme was taking shape, many courses were backing off agronomic practices and courses were rolling greens instead of mowing during this heat. If courses were mowed, mowing heights were raised in order to reduce stress as well. One of the hardest challenges during this type of heat is to be judicious with using water across the entire golf course. At times in extreme periods of stress and heat, the best thing to do is nothing at all, trying to push golf course conditions in this type of heat can lead to major problems in the future such as turf loss and invitation for turf pathogens to attack an already weakened plant.
During the previous two weeks, we have witnessed an increase in turfgrass diseases across the entire state. Many of these diseases we are seeing are occurring earlier than normal given the recent weather pattern, I would expect to see some of the following diseases to be seen more regularly across the region.
The hot and wet weather pattern favors development for pythium species. The speed in which this disease can establish and spread fungicides are essential tools for control. Many of our fungicides which are routinely sprayed on golf courses have little efficacy on the pathogen. Some of the fungicides that target pythium include cyazofamid, mefenoxam, propamocarb and fluopicolide. These fungicides are proven to be very effective against pythium. The use of phosphonate products and aluminum tris are great products to use when applied as a preventative and only when disease pressure is low to moderate.
As I mentioned two weeks ago brown patch is starting to become more active. Many fungicides are available to control the pathogen and many of the same products that are used to control dollar spot have efficacy against brown patch as well. However, some of the SDHI fungicides which are used to control dollar spot have very little activity against brown patch, so make sure to check the label. Before we move to some interesting diseases found in the state, situations where disease pressure is high, having more than one active ingredient protecting the plant is crucial to control multiple turf pathogens. Given the multiple diseases present on many courses no one fungicide will be able to control all of them with one single spray.
One disease I haven’t seen that often which was found in Illinois this week is gray leaf spot. Gray leaf spot is a major concern for courses and athletic facilities that manage ryegrass playing surfaces. The disease is typically seen in late summer and is easily a month early this season. This disease much like pythium requires preventative fungicide applications to effectively control the pathogen. The QoI fungicides are some of the best to control the pathogen, however resistance has been documented and these fungicides may provide little to no control.
Our old friend white leaf from last year may be back in the area again this year. Last year many courses across Chicagoland and Wisconsin saw this relatively new disease move into the area. Symptoms include bleaching of the entire leaf blade and can be seen on bentgrass and bluegrass. It’s believed that this disease is caused by a phytoplasma that is transferred from plant to plant by insect vectors. While the disease appears to be mostly cosmetic we have seen the disease infect all heights of turfgrass from roughs to putting greens. Last year the first report of white leaf was in late July, this first report is about a month early compared to last year. This will be something we will monitor as the growing season continues.
Crabgrass is being found on many playing surfaces across the state. This grassy weed can cause problems and take over fine turf areas if not controlled. Pre-emergent herbicides are strongly recommended for control partially because post-emergence control is more effective when the plant is young. Once crabgrass matures, control becomes more difficult. Monitoring areas where crabgrass is a problem should be noted for pre-emergence control next spring so that populations can be controlled. A popular product to control crabgrass as a post-emergence herbicide is quinclorac, however quinclorac does not control goosegrass which can be confused for crabgrass especially on closely mowed areas.
Beetle populations have been noticed across much of the Great Lakes region. Japanese beetles have been very noticeable here in Illinois, while further east masked chafers have been taking over putting greens. Taking the activity of the adult beetles into account many of our insecticides to control white grubs should be on the docket to go out in order to reduce their impact this fall.
Any questions or concerns don’t hesitate to contact me,
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