The Summer of 16

This article was written by Steve McDonald. He is one of the foremost consultants in the mid-atlantic region and is highly sought after for presentations at turf conferences around the country.

Relentless July and August Leads to Major Turfgrass Problems
16 August 2016

Turfgrass Disease Solutions, LLC

Over the past three weeks, I have visited more than 65 golf courses in Delaware, Maryland, New
Jersey, New York and Pennsylvania and there is one common theme, stressed turf due to the relentless
weather since mid to late July. The recent high day time temperatures, warm nights, humidity, intense
sunlight, wind and then spotty thunder storms have placed incredible stress to all cool season fine
turfgrass areas. The weather has not discriminated amongst private nor public clubs, high budget nor low
budget courses - every golf course is showing signs of stress in some regard. It has been a brutal season
to try to maintain green speeds, manage moisture and playing conditions. Due to the varying climates,
budgets, ages, and designs throughout the region, golf courses should not be compared to one another.
The growing season of 2016 is bringing chronic issues such as air movement, drainage, shade and weak
species to the fore front.
The most common problem I have encountered, especially in regions that are receiving rainfall, is
severe wet wilt to fairways, tees and greens. Wet wilt is a physical problem in which the soils are
saturated and the grass cannot transpire water to cool itself because of poor air movement and high
humidity levels. This has been most commonly observed in low lying areas of fairways, tees and greens.
Most commonly, it is complete decline or the only live grass is in aeration holes from this spring or last
fall. Wet wilt is very difficult to manage and can take up to 10 days to fully show up, especially on higher
cut tees and fairways. Typically, you will see that golf cart tire tracks wilt quickly and then decline even
when the soil moisture is adequate. If you are experiencing wet wilt, be conservative with mowing
heights and use solid front rollers. Rolling greens is a significant stress to thin turf. On fairways, in the
short term, limit cart traffic and restrict to roughs or paths. Don’t be afraid to preventively syringe turf
that is showing signs of wilt with adequate soil moisture. Long term, explore options to improve drainage
and air movement.
Dry wilt is also a problem for many golf courses not receiving rainfall in some regions. This
places an incredible load on the staff to manage moisture with hoses and overhead irrigation, which is
tough in the heat. If you are in a dry period, be sure to check that irrigation heads are properly
functioning. Far too often an irrigation problem shows up when the stress shows up and with the heat we
have experienced, it’s a slow road to recovery.
Beyond lack of water or too much water, is decline in the poorest growing environments. Air
movement is the most important growing environment consideration during warm, humid periods. Air
movement is needed for fine turf to be able to cool itself following light applications of water (i.e.
syringing). If there is no air movement, the turf in that environment can be 8-12ᵒF or more warmer than
turf receiving air movement naturally or through fans. Fans have completely changed greens
management in areas where trees and underbrush cannot be removed. Air movement is the key for
syringing to work. If the turf does not dry in between syringing, the effects are minimal and the turf will
begin to thin.
Mechanical stress is showing up throughout the region, especially in shaded areas. Mechanical
stress, although self-inflicted, is tough because superintendents are trying to produce a playable golf
course. The two most common mechanical issues I see are roller damage to the collars or mower stress
from turning or to the edges (clean ups) of greens. Be sure to watch staff turn mowers and use rollers to
be sure they are properly completing the task and adjust heights if mowing is skipped. Skipping mowing
may be needed during droughty or wet conditions but if skipping mowing, be sure to assess the height of
cut and not remove too much tissue in a single mow. You will be able to work the height back down in
time, but the initial scalp can cause issues under the current environment.
Disease pressure has been extremely high and every major turfgrass disease has been observed.
Brown patch and Pythium pressure has been high for the past three weeks. For those of you maintaining
perennial ryegrass, I have confirmed gray leaf spot over the past week- this disease can be incredibly
damaging under stress. In some of our trials, we are seeing tighter spray intervals and high rates work
best but nothing will provide 100% control in extreme conditions or saturated, humid conditions.
Preventive fungicides should be applied as needed. If curative control is attempted, be sure to have the
disease properly identified and use the best course of action.
Annual bluegrass weevils have been significantly damaging bentgrass fairways and tees for the
past 3 weeks. We have found early instar white grubs in some of the untreated plots in our research trials
so be sure to scout for them if you are seeing wilt or unthrifty turf. Be sure to scout for insect pest and
treat accordingly.
In a quick outline, these are just a few of the major observations I have had in my recent visits.
Other common themes include: elevated amounts of phytotoxicity (injury from commonly used plant
protection agents), elevated plant parasitic nematode levels, physical injury from aggressive golf shoes
and damage from venting or spiking greens and/or sand topdressing on weak and/or stressed turf. For
those of you considering aerification in the near future, please assess the health of the turf before aeration
or use a less aggressive technique. Aeration should not be looked upon as a tool to renovate weak turf,
but rather a tool to promote long term health. Aerification of weak turf in August can lead to weak turf in
September and October which are two of the most important golf months in the Mid-Atlantic region.