Turfgrass Scouting Report: 4/22/18
Most of the golf courses in the area are beginning to turn the corner towards spring. This time of year, it is hard to keep the grass from greening up with the amount of sunlight that is becoming available. The sun angle this time of year is equivalent to the sun angle during the 3rd week of August. That being said, mother nature has done almost everything else possible to delay green-up in much of the state.
Near record cold temperatures to start the month of April has limited spring green-up. April 2018 was the 4th coldest start to April in Chicago history. Not to be outdone, but Rockford was able to clock at #1 with it being the coldest start to April for that city in history. The cold temperatures and recent snows have also kept many of our trees and shrubs from leafing out.
Something I have noticed (at least in areas from Chicago southward) is that the poa is gaining ground on creeping bentgrass. There is an unfortunate temperature sweet spot where annual bluegrass resumes functionality and growth before creeping bentgrass. This leads to a transition in the population dynamics.
At the Midwest golf house, we have a new putting green that is being established. We specifically reduced the seeding rate of creeping bentgrass in an effort to get natural populations of poa to germinate and colonize. This would allow us to conduct poa control research trials in the future. During this process, it has been interesting to see how much ground the poa has gained on creeping bentgrass this spring.
Many folks are using growth covers in an effort to kick start the creeping bentgrass. As much as I harp on the idea that tarps create a perfect nesting ground for fungi, there are many success stories using these covers. The covers help increase the air and soil temperatures underneath. Turfgrass roots and shoots grow much more efficiently as mean temperatures creep above 50 degrees F.
Insects
Purdue’s turfgrass entomologist Dr. Doug Richmond provided a nice reminder that, despite the cold temperatures this season, insect pests such as black cutworms can be problematic this year.
In addition to black cutworms, now is also a good time to scout for bluegrass billbugs.
Weeds
Controlling annual bluegrass seedheads will be on the minds of many superintendents this week.
I first observed annual bluegrass seedheads on April 13th, and I am seeing more and more in hot spot areas. Hot spot areas include poa grown in south facing slopes or in rough areas. I have not seen seedhead production yet on annual bluegrass putting greens.
According to GDDtracker.net, almost all of the northern half of the state is in the ‘target’ criteria to make applications for seedhead suppression. Looking at the long term weather forecasts, there should be less concern with cool-temperature induced discoloration when Primo is tank-mixed with Proxy.
Diseases
This is the time of year we should be checking soil temperatures closely to monitor our patch diseases as well as fairy ring. Soil temperatures in the southern half of the state are now in the lower 50’s. Northward, soil temperatures should creep above 50 by late next week. Those with a prior history of take-all patch and fairy should consider preventive applications to manage this diseases.
Fortunately, soils should have a chance to dry out. Saturated soils are conducive for take-all patch and Pythium root rot. Unfortunately, in other aspects, many folks have waited a long time to overseed certain areas and may have been counting on spring rains once the temperatures began to moderate.
I scouted the Sunshine course this week a noticed a familiar foe. Dollar spot. I am not seeing new dollar spot development, but rather, scars of old infection centers from the fall. New dollar spot development often occurs in close proximity to these old infection centers.
Now is a good time to start planning for season long dollar spot control. Fortunately, there are a number of outstanding products that can be used to combat this disease. In addition, there are new tools available to help time these fungicide applications. Most notably is the dollar spot prediction model developed by scientists at the University of Wisconsin.
The Smith-Kerns dollar spot prediction model uses 5-day average temperature and relative humidity measurements to predict the likelihood of dollar spot activity. This model has been validated in several locations throughout the United States. To use this model, superintendents can input onsite meteorological data such as temperature and relative humidity. After this input, the model will produce a risk index to alarm you of possible dollar spot activity. It is advisable to familiarize yourself with this model to determine which threshold works best for your location.
Twitter: CDGATurfgrassProgram
Email: jbenelli@CDGA.org
