8/3/2023 - By Dr. Paul Giordano

As I write this, we are smack dab in the middle of the summer season. This year has already proven to be a unique one, with early droughts in the Midwest and Northeast and excessively wet weather affecting much of the Southeastern U.S. Whichever situation you found yourself in, a lot of turf went into the summer stressed out. Now that the heat and humidity have set in, there are plenty of diseases ramping up. Here, I touch on a few that have been active as of late and provide some quick BMP recommendations.

Take-All Patch

Early drought and cool temps had bentgrass slow to wake up. Slow growth and stress brought on symptoms of take-all patch, a “chronic” issue on bentgrass roots that rears its head when suboptimal growing conditions persist. Historically a disease of newly established creeping bentgrass greens, more and more take-all patch is being found on a wide variety of bentgrass stands. Getting fungicides far enough down to protect bentgrass roots 8-10” in the soil is nearly impossible, so infections can occur on deeper roots and bring about symptoms under heat, drought, or other abiotic stress.

In areas with a history of take-all patch, it’s important to start fungicide applications in the spring when soil temperatures are consistently above 55^o F. Watering applications in with at least 0.2” of post-application irrigation will help protect the crown and upper roots as the pathogen “wakes up” from dormancy inside previously infected plant tissue. Curative fungicide applications are only marginally effective but can help to protect new root growth and stop symptoms from getting worse. The best approach for addressing affected areas is to encourage new root growth via cultural practices, and using biostimulant products that can stimulate root growth and promote vigor and viability.

Harrell’s products like Seaweed A+E, EarthMAX® Organic, and Mycorrhizae Pro are proven solutions that can help achieve this.

Summer Patch

Like its close relative take-all patch, summer patch has ramped up on Poa annua root systems for similar reasons stated above. Because Poa roots are much more shallow than creeping bentgrass, even a little summer patch can be highly detrimental to the health of your turf, especially under summer stress. On high-value surfaces, bi-weekly or monthly applications of DMI’s, QoI’s, or combination products targeted to the root zone, are important to keep the roots clean and functional.

A dedicated focus on root health and growth is also key in helping the plant to grow through underlying levels of pathogen infection which tend to be abundant in most turfgrass systems. A few products to help control pathogens and allow your roots to grow safely are Harrell’s ProtectMAX® Azoxy, Tebuconazole, and T-Methyl. The all-new ProtectMAX Fluoxastrobin SC is an exciting addition to the portfolio that offers excellent control of summer patch, take-all patch, and a broad array of other diseases when incorporated into fungicide programs.

Pythium Blight

As heat and humidity have ramped up, so have foliar disease pressures. Pythium blight can be a common problem in the transition zone annually but only tends to rear its ugly head in the north once every few years. In general, when daytime temps and relative humidity add up to above 150, it’s time to start thinking about treating Pythium blight. Many turf managers can keep low-to-moderate levels of Pythium blight in check with regular applications of potassium phosphites like Title Phyte® Systemic Fungicide, but when pressure mounts as it has more recently, the heavy hitters need to be used.

Active ingredients like cyazofamid (Segway®), mefenoxam (Subdue Maxx®), picarbutrazox (Serata®), and propamocarb (Banol) are all great options to keep on deck for those sweaty, soupy periods. Often, targeting low-lying areas that stay wet like drainage swales can save time and money vs blanketing entire areas for Pythium control unnecessarily.

Contact Your Harrell’s Rep for More Info

As the Bon Jovi song says – “We’re halfway there.” Who knows what the rest of the summer will bring, but given the current outlook, we’ll need to remain vigilant with scouting, identification, and strategic prevention of diseases through late summer/early fall. Harrell’s can help with up-to-date information related to cultural, nutritional, and chemical recommendations that can help specifically target your primary issues of concern – As a partner in your success, we want to ensure you’re effectively winning the battle against diseases and not simply “Livin’ on a Prayer.”

As always, if you have any questions about products, applications, disease, or how Harrell’s can help you develop your Balanced Approach Program, reach out to your local Harrell's Rep. We’re always here to help however you need.