Q: This summer, our Buckeyeturf email account received several pictures of dead or brown grass from turfgrass managers seeking advice on diagnosing the issue and making corrective measures.
A: Although we strive to accurately diagnose and answer these types of questions, it can be challenging – especially without a site visit. Like many turfgrass Extension programs throughout the country, our turf team is multi-disciplinary and includes a diagnostic lab where turf managers can send samples. However, diagnosing problems over email, text or social media presents challenges.
In summer especially, brown grass can result from various issues such as drought, heat stress, disease, insect attack or human error such as a fertilizer spill or incorrect PGR/pesticide application. It’s also common to see multiple problems simultaneously. For example, drought or heat-stressed grass is more susceptible to insect and disease attacks. I remember taking a turf sample to our pathologist Joe one summer, expecting one diagnosis and getting three. This underscores that turfgrasses are not sterile or static systems. The turfgrass system is a dynamic and diverse ecosystem of living organisms.
As the turfgrass pathologists at NC State recently stated in their timely post on disease diagnosis, “Turfgrass Disease Diagnosis: A Bit of Science and a Lot of Art,” 10^9 bacterial cells and 10^6 fungi can be found in 1 gram of soil in turfgrass systems. So, many pathogens are present at any time. Whether they cause a turf problem depends on the host species and current environmental conditions (think disease triangle). Often, the environmental conditions are not right, so even though the pathogen is present, there may not be any turf problems.
All of this is to say that diagnosing why turf is brown in summer is a complex-but-not-impossible challenge. It involves various turf management skills – using environmental data to predict problems, conducting agronomic testing, field scouting, accurate diagnostics, documenting, recording and monitoring. Each of these are excellent skills to possess and teach your crew. There are also some excellent resources to make the process easier to navigate. One of my favorite resources is Michigan State’s Growing Degree Day Tracker (gddtracker.msu.edu), which is used to estimate the growth and development of plants and insects and to schedule pesticide and PGR applications.
If a physical visit or phone call is not possible, here are some tips for digitally submitting pictures and questions to your local turf Extension team:
1. Identify the turfgrass species: Tell us which turfgrass species you are managing, as this will narrow down the possibilities. For example, I once visited a baseball outfield where the Kentucky bluegrass was dead and dying, but the other grasses like perennial ryegrass were alive. The culprit was bluegrass billbug larvae feeding on the bluegrass crowns, resulting in loss of roots and plant death. By quickly identifying the turf species, I was able to focus on problems unique to that species and carry out specific checks, such as the classic tug test.
2. Summarize recent chemical applications: Provide a brief summary of any recent chemical applications. Some herbicides, for example, can inhibit the germination of turfgrass seed and establishment.
3. Share history of seasonal problems: Include information about any recurring issues like grub infestations, damage from digging varmints, patches of rough bluegrass (Poa trivialis) going dormant or annual bluegrass (Poa annua) dying, disease damage and other anomalies. State when the problem typically occurs.
4. Provide supplemental documentation: Share any supplemental documentation you think might be helpful, such as soil and tissue tests, product labels, etc.
5. Send clear pictures: Send clear, wide-angle and close-up pictures. If you have bleachers or an elevated view, include that picture too. I once diagnosed an irrigation uniformity issue by walking up into the bleachers and recognizing the clear patterns. Include pictures of the affected leaf tissue or plant part. Take pictures of symptoms (e.g., leaf spots, discoloration, tissue collapse). If there are physical signs of a pathogen (fungal mycelium, fruiting bodies or other structures), take pictures of those as well. Signs are usually more visible first thing in the morning. Good pictures are imperative.
6. Act quickly for severe diseases: If you suspect one of the more devastating turf diseases and are losing turf quickly, call us and get a live sample to your local turfgrass diagnostic lab asap. Follow their turf sample submission process to the letter. They’ll have directions on how to drop off or mail live samples.
Pamela Sherratt is a sports turf extension specialist at The Ohio State University.
Questions?
Send them to Pamela Sherratt at 202D Kottman Hall, 2001 Coffey Road, Columbus, OH 43210 or sherratt.1@osu.edu
Or send your question to Dr. Grady Miller, North Carolina State University, Box 7620, Raleigh, NC 27695-7620, or grady_miller@ncsu.edu
