Proper turf care is absolutely critical for golf course superintendents across the globe. From the tee box to the fairway to the putting green, each section needs to be meticulously cared for and watched over. Superintendents face a constant battle with pests, weeds and disease.
One of the pests that many superintendents may not even know about is the billbug. An incredibly small nocturnal insect most active between midnight and 4 a.m., the billbug can cause major destruction.
It’s an insect that Xi Xiong, associate professor of plant sciences, and Bruce Barrett, professor of entomology, are working to learn more about. The two are principal investigators, along with Doug Richmond and Laramy Enders (Purdue University), and Ricardo Ramirez (Utah State University), on a $320,000 grant from the USDA National Institute of Food and Agriculture (NIFA) to develop innovative integrated pest management tactics for billbug control. The team is looking to control the billbugs through early detection and while using non-chemical approaches.
The grant is part of NIFA’s Crop Protection and Pest Management program.
“Billbug damage is becoming more and more of an urgent issue for us,” Xiong said. “This damage is obviously detrimental for superintendents. We’re hopeful that we can find ways to help control this pest and save superintendents money when it comes to caring for their courses.”
Billbug females bite off a small piece of the grass stem and lay their eggs in the stem. Once the egg hatches, the larvae turns the stem into their home, eating through the plant and causing devastating damage to the grass. As the billbug grows, it bores its way into the grass crown, feeding on the roots. That damage is oftentimes attributed to drought conditions or winterkill, due to the billbug’s small stature and nocturnal nature. The misdiagnosis can eventually lead to the death of the turf.
“It’s incredibly difficult to identify billbug damage,” Xiong said. “The adults are super small, about seven to 10 millimeters in length. The larvae are obviously even smaller. Oftentimes, a superintendent will think they just have drought or white grub, another group of root-feeding insects, damage and treat for those conditions. Those treatments can start to add up and become costly.”
There are multiple species of billbugs. The two most common species found in Missouri are the bluegrass billbug and the hunting billbug. They are two of the nine species that are problematic for turfgrass managers, with each of them being regionally specific. The bluegrass billbugs are most commonly found roaming in Kentucky bluegrass. Hunting billbugs are tougher to peg down. That species is generally associated with bermudagrass.
“Typically, the hunting billbug was thought to be most common down south, in Florida, Georgia and Texas,” Xiong said. “We never really considered it to be an issue for the zoysiagrass we have here. We’ve found that to not be true, however. The zoysiagrass cultivar ‘Meyer’, that is commonly used in this region, has a thick stem, making it easier for the hunting billbug to lay its eggs. The fairways in Missouri are dominated by zoysiagrass.”
To capture and study the two species of billbugs on golf courses, Xiong developed a device to catch the insect. Crafted out of PVC pipe and fitted with a filter, the devices were spaced out across a local golf course to collect the billbugs.
Once back on campus, the billbugs were separated according to species. Barrett set up an experiment to see if the hunting billbugs had a preference on which grass they preferred. The billbugs were exposed to tall fescue, Kentucky bluegrass and zoysiagrass. Those are the three primary turfgrasses used in fairways and roughs on Missouri golf courses.
Barrett and Xiong published a paper on their findings, which is one of the first to investigate some fundamental aspects of the chemical ecology of the hunting billbug.
The PVC collection method wasn’t a true way to control the billbug population, so Xiong began to brainstorm other possible methods of non-chemical control. Those thoughts led Xiong to seek how synthetic turf is treated and cared for.
A sweeper is used to collect the debris and trash that could end up in a synthetic turf. Xiong thought the same tool could be used on the golf course turf.
“We rented a sweeper from the Columbia Public Schools and did a quick trial,” Xiong said. “In a 45-second sweep, we picked up 50 billbugs. Right then I felt like we had a mechanical approach that could work for control.”
The sweeper features a rubber brush that doesn’t damage the natural turf. It picks up the billbugs and deposits them in a collection bin. It doesn’t harm the billbug, either.
“We can’t install the PVC traps across the entire fairway,” Xiong said. “We feel like the sweeper is a great alternative. There is still a lot of work to be done, but we’re on the right path.”
Xiong and the team are continuing to dig deeper on the billbug problem. They are currently working on seeing how long a billbug can live, as well as better ways to identify the larvae. Each of the adults is distinctive – the larvae are not.
“If you don’t know what species you have, you don’t know the proper way to control them,” Xiong said. “It’s almost impossible to find larvae in the soil. We had a student who worked on this for two years. Every month, we would take soil cones on the golf course, we found one larvae in the soil.”
Xiong is also working to identify the best times to run the sweeper. Xiong said previous research has shown that billbug adults are most active during a few weeks in the spring and fall. Finding the right season to sweep is key.
“For me, this is a problem and we’re doing our best to solve it,” Xiong said. “That is my approach. We’re excited with what we have found out and we’re focused on continuing this research.”