Cool End of August
While temperatures are running a touch above normal for the month, it sure hasn't felt like it. Despite a few temperature spikes, averages have been kept near summer normal by the "high low" temperatures instead of scorching hot daytime temperatures. Particularly in the last five days, August has felt like late September/October football weather, which has been a rarity in the region in recent memory. Perhaps Mother Nature is feeling a bit poorly about the rough treatment last summer, and is providing an early chance to get cool season turfgrasses back on their feet (see below). A temperature spike is expected to round out this week, but cooler than normal temperatures are expected to return and greet September.
While temperatures may be mild, the storm clouds have been far from timid. Over the past month, the region has been the nation's bullseye for heavy rainfall, particularly eastern Kansas and Kansas City which has absorbed (or had run off) considerable precipitation. The drier conditions expected to start September will be welcome in these areas, whereas in most summers drought conditions are a constant companion and many are wishing for rain.
Too early to talk winter? The Old Farmer's Almanac has predicted a "snowy, icy, icky" winter for much of the region (https://www.almanac.com/old-farmers-almanac-2020-winter-forecast), with at least seven snowstorms sweeping the nation. For reference, last year's winter was forecasted as "teeth chattering cold with plentiful snow". While not strictly scientific and conflicting with other long range forecasts, the adjectives snowy, icy and icky from the old farmer don't instill confidence that winterkill pressure from 2019 won't recur in 2020.
Rain, Rain Set to Stay Away?
Foliar Diseases Explode on Putting Greens
Roots Love Air-ification
Not difficult to observe where tines plunged into this soil profile.
August Active Anthracnose
Augustus was the first emperor of the Roman Empire, and in honor of him the month of August bears his name. Like Augustus, anthracnose tends to rule over bentgrass putting greens in August when bentgrass is at its lowest point and unfortunately set for conquer. Several bentgrass samples over the past two weeks have had considerable basal rot anthracnose activity and decline. This pales to last year when Augustus Anthracnose reigned supreme and waged war all summer long, but now he's back to collect his taxes.
Cool and comfortable temperatures bring mostly good news for superintendents, but in my experience when mild temperatures first hit in fall, or during an unexpected cool down in summer, anthracnose normally strikes. From a physiological viewpoint, this makes sense. Bentgrass is beaten down by higher temperatures and the pathogen which is omnipresent on leaf blades sinks its teeth down to the base of the plant. The kicker here is that anthracnose is a low nitrogen disease. Temperatures cool off, bentgrass wants to grow, and spoonfeeding doesn't supply enough juice. To compound the issue in late summer, bentgrass roots have also been beaten back all summer long by high temperatures, so the plant can't take up soil available nitrogen efficiently. Reacting dynamically to early cool temperature treats by bumping up the nitrogen is suggested to mitigate anthracnose activity.
In the past two years, we have observed damaging basal rot anthracnose on 'Penn A-4' and 'T-1' bentgrass cultivars. This contrasts with the previous notion that the newer varieties are not susceptible to the disease, particularly when compared to consistent observations on 'Penncross', 'Pennlinks', 'SR1020', 'Providence', 'Seaside', etc. Looking back on limited NTEP observations of anthracnose susceptibility, some of the newer cultivars do get anthracnose and therefore monitoring and control of this disease should be considered even on newer bentgrass varieties.
In curative situations, a contact and systemic fungicide tank-mix is recommended. Resistance of the anthracnose pathogen to several fungicide classes has been reported in other areas of the country, but it's unclear how widespread resistance may be in this region. Therefore, and particularly at this point in the season after exposure to a number of applications may have already occurred, employing more than one effective active ingredient for both preventive and curative applications is recommended. Also don't forget employing proper cultural practices, which are summed up very nicely in this Feb 2018 GCM article by Drs. Murphy, Clarke, and Inguagiato.
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Extension Turfgrass Pathologist
University of Missouri