2/27/2023 - By Dr. Paul Giordano

Grass dies. It’s inevitable. Every year without fail some of our turfgrass areas will succumb to the various pressures of Mother Nature. Often, we look for concrete answers and want to point the finger at one guilty culprit like a movie murder mystery. But the reality is, grass dies – especially on highly maintained areas like putting greens, tees, or fairways. However, it’s more complicated than a single factor, which is where the phrase “death by a thousand cuts” really comes into play.

Diagnosing the Problem

Dr. Jim Kerns and Lee Butler have one of the most active and respected turfgrass diagnostic laboratories in the country. Each winter, they put out an annual review discussing the collective results of their sample submissions and diagnostic analyses. One of the biggest takeaways from this report is that regardless of the turf type and where the sample comes from, most of them end up with “no pathogen found.” Put another way, the dead/dying samples submitted for disease diagnosis are not primarily affected by a pathogen at all – they are suffering from an abiotic issue.

Pest Thresholds

So, what does this mean? To me, it means there’s always more to the story. I often think about pest “thresholds” and their relationship to turf health or survivability. Things like nematodes or the annual bluegrass weevil are often given population threshold ranges that are associated with turfgrass death or decline.

Overall Health or Condition of the Plant(s) in the Presence of Pests

This obviously matters –a healthy, high functioning plant with a robust root system will be much more capable of weathering some minor feeding or low levels of root infection verses a weak, shallow rooted plant. One good example - Every summer I get to visit dozens of golf courses and I often take small turf samples out of areas of concern for a better look under the microscope. If you observe Poa annua or creeping bentgrass roots closely during the summer months. Invariably, you will find some level of ectotrophic runner hyphae hanging around and inside these root systems.

These hyphae are associated with the fungal pathogens that cause summer patch and take-all patch. But how much is too much? At what point would we consider these to be a “primary” cause of turf decline? Well, that is where the bigger picture and a well-trained diagnostic eye is needed.

Plant Strength is Important, and so is Looking Ahead

Point being, A healthy, well rooted turfgrass plant can likely withstand a good amount of this type of infection and show no above ground symptoms of decline. Conversely, a stand of annual bluegrass with roots only 1.5 – 2 inches deep will likely show signs of wilt or even death, with only a minor compromise by the summer patch pathogen. Throw in other compounding factors such as Pythium diseases, nematodes, traffic, shade, drought…etc. and the weaker plants don’t stand a chance.

One of these root systems can tolerate much more disease, nematode, insect, and abiotic pressure than the other.

Spring is a great time to start thinking ahead. Most turf managers are already incorporating preventive measures for destructive diseases and insects like summer patch, fairy ring, ABW, and nematodes. We make applications that are specifically timed and targeted to protect above and below ground tissues from these pests. At the same time, we can help improve the efficacy of our fungicides/insecticides, encourage resilient growth and healthy development of new roots.

A Few Product Recommendations

Several products have been proven to aid in naturally stimulating root function, photosynthetic efficiency, and overall growth. Bio stimulants like Amino Pro V, EarthMax, BioMax 4-0-0, Seaweed A+E, and Mycorrhizae Pro are excellent tools to incorporate into soil-targeted applications. These scientifically proven products are included into the Harrell’s Balanced approach programs aimed at root growth and the promotion of turf health. Controlling the pests are the tip of the pyramid. The base or foundation to which a healthy stand is built comes from within the plant.

Controlling destructive diseases and insects is a necessary step in achieving “plant health” - but it’s only the tip of pyramid. The base or the foundation that plant health is built on includes:

·         Balanced nutrition

·         Stress mitigation

·         Photosynthetic efficiency

·         And optimizing root growth and function from the inside out

To learn more on how the Harrell’s Balanced Approach and full line of plant health offerings can help you, reach out to your Harrell’s Territory Representative.

Resources

·         https://www.youtube.com/watch?v=mi-Vu8G_3ws

·         https://www.youtube.com/watch?v=gFFcKjvOTMk&t=55s

·         https://www.youtube.com/watch?v=yzQ-gHvXaHQ&t=20s

·         https://www.youtube.com/watch?v=aXo6aI5uWdA&t=46s

·         https://www.youtube.com/watch?v=aNlAyYva6FM