Most damage from white grubs is indirect through animal foraging. An insecticide applied once adults are seen is the most effective control.
© courtesy of bayer
Paul Giordano

Whether it’s a global pandemic, hurricanes, tornadoes or floods, disruption on the golf course is unfortunately becoming commonplace. Regardless of the cause of the disruption, there are some key practices to keep in mind when attempting to manage high-quality turf with limited resources. The following are some thoughts from an agronomic perspective.

Zac Reicher

As of this writing, golf course operations are highly varied across the country, from no golf and no maintenance, to no golf and limited maintenance, to open golf with limited maintenance. The one consistency is that staffs are typically limited in number of crew members. In addition, some crews consist of salaried staff from hospitality or the pro shop. Thus, superintendents must be selective and intentional about prioritizing tasks based on the current staff. Mowing is usually the first major change in maintenance, increasing mowing heights and decreasing mowing frequency. Aggressive growth regulators and/or topdressing are then employed to further limit the mowing requirements.

“An ounce of prevention is worth a pound of cure” has never been truer than it is now. With major staffing concerns and unpredictable budget constraints, preventative pest control is even more critical than in a typical year. Timely, preventive applications made now could save tremendous labor and money required to curatively control a biotic pest or worse yet, repair areas damaged by pests. Furthermore, most are relying heavily on growth regulators to manage mowing requirements, which could negatively impact damage recovery. Lastly, nobody can reasonably predict when play will fully resume with golfer expectations of mid-season conditioning.

Annual bluegrass weevil is difficult to manage but are best controlled by a multi-pronged approach early in the season.
© courtesy of bayer

Limiting root problems should be at the top of the priority list. Diseases like summer patch, fairy ring, Pythium root rot, mini ring, etc. are relatively easy to control when addressed preventatively. Delayed applications could allow infection levels to build, leading to irreversible root damage and eventual thinning turf. Applications of a labelled DMI fungicide (like Mirage® Stressgard®) at 2” soil temperatures of 55-65°F will control a multitude of root diseases like summer patch, take-all patch and fairy ring, plus this application will also control foliar/stem diseases like brown ring (Waitea) patch, anthracnose and dollar spot. Consider including a fungicide labelled for Pythium root rot (like Banol®, Signature® Xtra or Segway®) in this application to give added insurance against the always present oomycete pathogens that can wreak havoc if left unchecked.

Plant parasitic nematodes are also best addressed at this time of the year when soil temps reach the critical temperature of 55-65°F. If nematodes have been a historic problem on your course, consider an effective nematicide (like Indemnify®) in this tank mix. Two or three applications of this tank mix on a 28-day interval could provide long-term control of the most problematic diseases and nematodes deep into the summer. This tank mix may seem very complex, but could save tremendous long-term time and labor.

Most insects are best controlled preventatively and if left uncontrolled, can cause significant direct damage or cause indirect damage from animal foraging. Adults of the annual bluegrass weevil should be targeted in the spring as they migrate into fairways as well as first generation larvae to limit future generations throughout the year. Early applications for annual bluegrass weevil are critical to avoid long-term damage. Larvae (white grubs) are the damaging stage of many annual beetles, including Japanese beetles and masked chafers. Most effective and efficient insecticide applications are made when adults are first seen in June or July.

Mole crickets in the Southeast should be controlled early, during nymph hatch. A preventative, long-lasting insecticide (Chipco™ Choice™) application made by licensed contract applicators provides the most effective control of mole crickets. Curative “chase & spray” programs later in the year are difficult and can cause very unsightly conditions.

One of the best ways to stay ahead of problematic weeds is properly timed preemergence (PRE) herbicide applications. PRE herbicides applied in the spring when 4” soil temperatures reach 55°F effectively control annual grasses such as goosegrass, crabgrass and foxtails. In tougher climates, a second application is justified shortly after you start seeing weed seedlings in untreated hotspots. Being late or even missing PRE herbicide application requires more difficult rescue applications of postemergence (POST) herbicides and increases risk of turf injury. POST herbicides require accurate timing on juvenile weeds and possibly multiple applications for more mature plants. Goosegrass, in particular, is relatively easy to control with PRE herbicides (Ronstar® or Specticle®), but POST control is much more difficult. That being said, combinations of PRE/POST goosegrass products will be important for managing resistance in more typical years.

Fairy ring can be problematic in all turf types but can be controlled preventatively with DMI fungicides early in the season.
© courtesy of bayer

Avoid the temptation to tank mix products that don’t fit together in order to save time. Foliar fungicides or plant growth regulators should not be combined with wetting agents, nematicides or fungicides which are targeted to the root zone. Conversely, don’t be afraid to include multiple modes of action for the same pests such as a PRE and POST herbicide for annual grasses or a contact fungicide, plus a systemic for diseases like dollar spot. Resistance management may not be the No. 1 priority right now, but it should always be considered when applying pesticides.

If possible, take advantage of no/limited play with lower expectations. Assuming adequate labor, this may be a great time to catch up on aerification, vertical mowing and/or topdressing you’ve been unable to do in past years. If you’re in the Bermudagrass overseed market, a course closure may be an opportunity to transition ryegrass out early to maximize Bermudagrass growth and improve weak stands.

Please recognize that your manufacturers and distributors are keeping their distance during this time, but they are only a phone call, text or email away. Reach out if you have questions, need assistance or just want someone to bounce ideas around with. ?

Zac Reicher, Ph.D., and Paul Giordano, Ph.D., are members of the Bayer Green Solutions Team.