It’s Raining, It’s Pouring, the Old Fungus is Not Snoring!
The current wet weather pattern across much of the east coast will have an effect on disease pressure over the next few weeks on all turfgrasses. Fungi love water and when conditions are not favorable for turfgrass growth, the little buggers take advantage of this situation and wage war against our well-manicured turf stands. If you haven’t learned this during your journey, you soon will. Don’t fret too much though, if you are a wise turfgrass manager you have deployed preventative measures in the form of fungicide applications. Remember, fungicides actually do work and work quite well when applied correctly at the right time. The primary diseases to be concerned with in the Carolina’s right now will be Pythium diseases (all turf), leaf spots (bermudagrass), and large patch (warm-season turf).
As mentioned in a tweet we sent out last week, the current weather conditions are ideal for Pythium blight on bermudagrass putting greens. Any decent Pythium fungicide such as Subdue, Segway, Banol, Stellar, Appear, or Signature (in no particular order) should do a nice job of preventing this disease. You will likely have to make repeat applications every couple of weeks until the weather changes. Rotate through the different chemistries to help with resistance management.
In addition to bermudagrass, we may observe an increase in Pythium blight diagnoses on multiple turfgrass species depending on location and growing conditions. If you are managing high-end turf, go ahead and protect yourself with a fungicide application.
Finally, we may observe Pythium root rot on creeping bentgrass putting greens. This will likely occur in areas with poor drainage first or follow drainage patterns, however don’t rule this disease out in well drained areas because we have observed it there many times also. Remember, there are dozens and dozens of Pythium species that attack turf and they all have different temperature ranges … don’t believe the old wives tale that Pythium only attacks during hot weather.
We know through tracking samples in our database that leaf spot diseases on bermudagrass primarily occur between the months of July and October, especially during rainy/cloudy periods. Since this does tend to coincide with Pythium blight, it’s best to tank mix your leaf spot fungicide with your Pythium blight product for best turfgrass quality during these yucky weather periods.
Finally, there will most likely be an increase in large patch incidence with all the wet weather. This disease attacks all warm-season turfgrasses, however it tends to be most severe on centipedegrass, St. Augustinegrass, and zoysiagrass. Once infections occur, fungicide applications may stop further spread however don’t expect a miracle recovery now that these turfgrasses are slowing their growth down significantly due to shorter day length and cooler soil temperatures.