Tree Trouble, USGA Central Region Update

Posted on September 29th, 2021
By: Paul Jacobs, agronomist, Central Region

Trees can be a wonderful asset to any golf course, but when they begin to negatively impact turf health or playability, they become a detriment.

The growing environment that turf occupies is the most influential factor on turf health and reliability – bar none. There are differences in light requirements and “ideal” growing environments depending on whether cool-season or warm-season grasses are grown but, for the most part, providing full-day sunlight is the most desirable situation.

For warm-season grasses, winter shade can be particularly troublesome. This past winter caused significant winterkill and, not surprisingly, areas that received heavy shade during the winter were often the most severely damaged. Warm-season grasses also need plentiful sunlight during the summer months to perform well. It is important to keep in mind that the sun’s path changes significantly from winter to summer when evaluating growing environments. The sun rises more than 60 degrees farther south during the winter months than it does during the summer and how high it travels also varies significantly.

During recent Course Consulting Service visits it has also become apparent that several insect pests and parasites have been causing significant damage to trees in the central U.S.

  • The emerald ash borer (EAB) has been spreading from the Upper Midwest for the past 20 years and has been identified in most states in the region. For those not familiar with the EAB, it infects and kills ash trees within a couple of years. Facilities in areas with high populations of the EAB have been preemptively removing ash trees because they become brittle and unsafe once they decline. There are options for treatment, but most courses have only been treating if there are a handful of important ash trees on the property.
  • Oak gall wasps have been causing horned and gouty oak galls on oak trees – primarily pin oaks – in Missouri. Typically, this is not a major concern but several courses have seen a surge in the level of damage and quantity of galls on pin oaks. The best course of action is to prune the infected branches to prevent the issue from spreading.
  • Mistletoe is another pest that may require management to keep trees healthy. Although not as damaging as other pests, it acts as a parasite and can spread throughout a tree population as seeds are deposited from tree to tree. Pruning branches where mistletoe is growing is the best management method.

Removing trees that have a direct negative impact on turf health and playability should be the top priority, but it is important to keep in mind that other trees need to be managed to remain healthy. For this reason, it can be beneficial to reduce the overall population so that resources can be allocated to keep the remaining trees as healthy as possible. If you would like help developing a tree management plan for your golf course, do not hesitate to contact your regional USGA agronomist.

Central Region Agronomists:

Paul Jacobs, agronomist –

Zach Nicoludis, agronomist –

Information on the USGA’s Course Consulting Service

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