UK turfgrass research targets the annual bluegrass weevil to help protect Kentucky’s golf courses

At the University of Kentucky Martin-Gatton College of Agriculture, Food and Environment (CAFE), the Department of Entomology is studying a newly arrived pest affecting turfgrasses commonly found at golf courses.

The annual bluegrass weevil (ABW), a small weevil (a type of beetle under 1/64th of an inch as an adult), is considered one of the largest threats to golf course turfgrass in the Northeastern United States. More recently, the ABW has made its way to the Southeast, causing golf course superintendents and managers to rethink how they protect their courses from damage caused by this very costly pest.

ABW adults and larvae feed on short mown turfgrasses commonly found in golf course fairways, collars, approaches and putting greens. Adults feed on individual leaf blades. However, larvae feed inside the stems of grasses, and when big enough, begin feeding on the crown of the plant, which is the growth point located at the base of grasses. If left unchecked, ABW can kill large swards of turfgrass. This is especially problematic on golf courses where turf is valued for its aesthetic appeal and used as the playing surface for the sport.

It is critical to first understand ABW’s seasonal activity here in Kentucky to better manage the pest, said Caleb Wilson, Ph.D., assistant professor of Urban Landscape Entomology at Martin-Gatton CAFE.

“We know a lot about the ABW’s biology and seasonal activity in the Northeast, but we don’t know when the different life stages are active here in Kentucky and when populations peak in abundance,” Wilson said. “A big part of this research project is to better understand the ABW’s seasonal activity in different parts of the Bluegrass region where this critter is established so that superintendents across Central Kentucky can manage it more effectively.”

The Kentuckiana Golf Course Superintendents Association (KGCSA) provided a gift to fund this project to help advance UK’s turfgrass research in the region. UK, in partnership with the KGCSA, wants to reduce pest management costs for golf course superintendents and managers — helping make better decisions to treat and produce healthier turfgrass in Kentucky.

“The findings from this project will help superintendents better determine the timing and frequency of insecticide applications,” said KGCSA president Matthew E. Shallock. “As the cost of turf management products continues to rise, reducing unnecessary treatments is increasingly important. By identifying when and where control measures are truly needed, this research will help golf course managers make more informed decisions, improve resource efficiency and enhance turf health across golf courses throughout the Kentuckiana region.”

Syngenta has also supported UK’s turfgrass and ABW research.

“Supporting graduate research at the University of Kentucky allows us to combine academic expertise with real-world industry challenges,” said Matt Giese, Midwest technical service representative at Syngenta Professional Solutions. “The annual bluegrass weevil is a destructive, complex pest requiring precise application timing to target the right life stages at the right moment. This collaboration advances our understanding of ABW behavior, helping superintendents maximize control, protect turf quality and make more targeted, sustainable management decisions.”

Sampling and lab analysis process

This funding directly supports UK entomology graduate student Grace Ferry’s turfgrass research while pursuing her master’s degree in entomology at Martin-Gatton CAFE.

Under Wilson’s mentorship, Ferry has been visiting several sampling sites each week to measure ABW’s annual activity in Kentucky’s golf courses. One of those sites is in Jessamine County, the location of the Champion’s Trace course at Keene Trace Golf Club.

Using a turf plugger, a tool designed to cut 6-centimeter cylindrical soil plugs from turfgrass, Ferry and her fellow researchers collect ABW larvae from the collars surrounding putting greens. The team also uses data loggers to record temperatures every two hours seasonally, which will be used to create growing degree day models to better track the ABW’s activity peak during emergence. The team also poured soapy water on the surface of ABW-infested turfgrass to get weevils to crawl upward so they can be counted.

For Carl Gray, superintendent at Keene Trace Golf Club, working with Martin-Gatton CAFE allows their team to be more proactive with their turfgrass management.

“The University of Kentucky continues to lead the way in the turfgrass industry,” Gray said. “Having the opportunity to work closely with Caleb and his team gives us an inside look at emerging practices, research and technology. Their partnership helps us evaluate what we're doing, identify opportunities for improvement and stay at the forefront of the industry.”

After her fieldwork, Ferry returns to Wilson’s lab on the UK campus where the larvae are extracted from turf plugs using heat lamps called “Tullgren funnels.” Larvae are counted and measured to determine how old they are. The data are then shared each week with golf course superintendents — providing a real-time update on how numerous ABW are and what life stage is most common, which allows superintendents to time treatments or determine how effective previous treatments were.

Ferry, who aspires to work in Extension one day, like the UK Cooperative Extension Service, appreciates the mentorship she’s receiving as a graduate student.

“They’ve been really amazing to work with,” Ferry said. “I really value the hands-on experience and doing fun research projects like this.”

Kenneth Clayton, senior agriculture Extension associate at Martin-Gatton CAFE, considers himself the middleman between the research and the golf course superintendents.

“They [Wilson and Ferry] are spending more time in the lab, and I’m spending more time traveling and providing education to assist the superintendents and managers where they are,” Clayton said. “With a newer pest like this, there are huge learning gaps, so it’s important that we are translating that science from our research to the golf course superintendents and managers so they can make timely applications and do their jobs well.”

Visit the Department of Entomology website to learn more.