Summer heat and the peak months of play are right around the corner. As a result, most courses are increasing the intensity of their spray programs to protect turf from injuries associated with disease activity, insect pests, localized dry spots and other stresses.
The sheer number of available plant protectants, wetting agents, growth regulators, fertilizers and biostimulants can boggle the mind. Unfortunately, some courses have learned the hard lesson that certain products, or combinations of products, can cause unanticipated and sometimes negative effects on turf quality. Some side effects are fairly obvious—e.g., foliar burn—while others can be far more subtle—e.g., wider leaf blades caused by certain growth regulators. However, it is difficult to document the positive or negative effects of a spray treatment when all the greens, tees or fairways are equally treated.
It should come as no surprise that turf injury on putting greens is far more serious than injury on tees, fairways or roughs. To avoid potential problems, many turf managers take the prudent step of testing new or unfamiliar products on part of a chipping or practice green before spraying all the greens on the course. Spraying only half of a small chipping green allows for comparison between treated and untreated areas, but the transition between the two can be fuzzy. The turf directly beneath the terminal spray nozzle receives the full rate of product, but the amount of applied product decreases as the distance away from the terminal nozzle increases because there is no overlap. The end result is a blurry transition zone between what is treated and what is not.
One simple solution is to place a small square of plywood or cardboard on the turf just before spraying. The turf under the plywood will not be exposed to the spray treatment, providing a well-defined “check area” to compare with the treated area. This comparison will help evaluate the positive or negative effects of the application. Be sure to mark the corners of the check area before removing the spray barrier for easy observation.
A small check area is ideal for evaluating the effects of new or unfamiliar products, whether they are applied alone or in combinations. However, a small check plot will not tell you which one of several combined products might be causing an issue.
When it comes to turf management, bad surprises seem more common than good surprises. If you are planning to try an unfamiliar product, be sure to “check” it out first.
Central Region Agronomists:
Bob Vavrek, regional director – email@example.com
John Daniels, agronomist – firstname.lastname@example.org
Zach Nicoludis, agronomist – email@example.com