Pest management consultants embrace an built-in method to battling rodents

A roof rat sniffs around a rodent bait station on Kiawah Island in August 2020.
Photo credit: Eric Benson, Clemson University

CLEMSON – Dogs may be man’s best friend, but rats have been his constant companions. For good or bad – more often the latter – rats have followed us wherever we go. Even luxury residential complexes are not immune.

Rodenticides – chemicals that kill rodents – are an important tool in the fight against rats. But pest control companies are trying to add additional weapons to their arsenal on Kiawah Island, South Carolina, where some of the community’s famous bobcats tested positive for the chemicals.

In an online training course from Clemson University on Aug. 20, pest control professionals who represent 85 percent of properties with pest control services on Kiawah and tens of thousands across the state examined ways to incorporate a variety of chemical dependency reduction methods, spokesman Donny Oswalt said : “Still offer a high level of control without harming the environment.”

The approach is known as Integrated Pest Management (IPM) and has been used in pest control for generations, especially on farms. President Nixon commissioned his teaching to be used in row crops in the 1970s. The process is particularly complicated in Kiawah, a rapidly growing living environment in what was once a swampy habitat for bobcats and the rodents and other wildlife they feed on.

Many homes on Kiawah Island are surrounded by thick vegetation, drawing a fine line between human and wildlife habitats.
Photo credit: Eric Benson, Clemson University

“Kiawah is a very sensitive environment, a complex environment. Basically there are thousands of structures in a jungle. Other vacation spots in South Carolina are similar, ”said Eric Benson, professor emeritus and Clemson Extension specialist, whose expertise is IPM on urban pests. “Fortunately, we can use a variety of tools – and we have a lot for rodent control – and reduce exposure to no target.”

The enemy on Kiawah is mainly the roof rat, so named because of the ease with which it climbs. The rodents, also known as ship rats, are common near ports and coastlines, but have become widespread in the United States. They’re also a treat for bobcats.

“Rooftop rats have displaced some of the most well-known pests in northeast Alabama, wherever we are and we are far from coastal cities or seaports,” said Oswalt, Ph.D. from Clemson University. Graduate and specialist in rodent IPM with more than 40 years of experience. He owns an Alabama pest control company, The Bug Doctor.

“They are agile climbers. You would certainly have no problem climbing the aboveground buildings on coastal islands, ”he said. “They deposit urine and / or feces and secretions in popular routes that use some kind of pheromone as a form of communication so that great-grandfather can tell future generations that he was here a few months ago.”

Oswalt is not exaggerating. With a lifespan of 5 months to 1.5 years, a female roof rat can have 4 to 8 pups per litter in 3 to 4 litters per year. Multiply that time by up to 180 pellets per day, and the need for rodent control is painfully clear.

“The list of diseases these rodents can transmit is mind-boggling. Roof rats eat our food, pollute our food, spread disease, ”said Benson. “According to the surveillance I carried out on Kiawah – just a couple of nights, so just anecdotal – the only rodents I saw were roof rats. It seems that mice are not a big problem as rats devastate other species. Understanding what rodents or rodents you have is very important as the control strategies can vary widely. “

It doesn’t take much access to food, water, or shelter to support rodents like roof rats. Small amounts of trash, like this one at a trading company on Kiawah Island, will attract pests.
Photo credit: Eric Benson, Clemson University

Pest control companies work with homeowners and business owners to determine the appropriate strategies for each individual case. Many do not contain any rodenticide at all. Proper hygiene is the first step. “Everyone has trash,” said Benson.

“Kiawah is a very unique living space with houses carved out of the natural landscape. You have a very small interface between the end of the natural vegetation and the start of the homeowner’s environment, ”Oswalt said.

“One of the techniques we use is to make the rooftop rat habitat inhospitable: reduce overgrowth of vegetation that can house rats, decrease clutter, eliminate artificial water sources and opportunities for rooftop rats to forage,” he said.

Grandpa’s old snap traps still work just fine, but they may not be able to inflict a bump on a rapidly growing rodent population.

Chemical agents are often used because they work quickly and can reach more rats at a time than mechanical traps.

After using various poisons to exterminate rats for centuries, humans developed a new type of chemical in the 20th century: anticoagulants. These rodenticides cause rats to bleed to death internally using a two-pronged approach: damaging blood vessels and preventing blood clotting, hence the name.

The first generation of these rodenticides like warfarin and chlorophacinone appeared in the 1950s. To be effective, these must be used in higher concentrations than more modern chemicals.

Faster, more toxic, second generation anticoagulants known as SGAs emerged in the 1970s and quickly became the preferred chemical control agent.

It is these SGAs that the biologists in the Kiawah Bobcats discovered, leading islanders, pest control companies, and Clemson experts to search for solutions.

“We are still collecting corporate customer information for the city, but we are confident that pest control companies have voluntarily removed at least 70 percent of city accounts from SGA usage,” said Steve Cole, director of Regulatory Services at Clemson, which houses the State Department of Pesticide Regulation and other government regulators.

Many have adopted IPM.

“We cannot think of this as a unique problem. We need to look at how to find balance, ”said Jim Wright, executive director of the South Carolina Pest Control Association. “Using rodenticides is one of the tools in your toolbox. You have to think a little outside the box. “

Construction continues on Kiawah Island and new plots are carved out of natural areas.
Photo credit: Eric Benson, Clemson University

When asked during his lecture whether a return to first-generation anticoagulants was preferable, Oswalt urged caution.

“All rodenticides have their own risks. In many cases I feel safer for my customers with SGAs. In my experience, pets who accidentally ingested SGAs came out better than non-SGAs, ”Oswalt said. “If a homeowner’s award-winning poodle has eaten a bait that you handed out, the homeowner is not going to care for a wild animal. She won’t come and thank you for protecting the wildlife and her dog died anyway. “

Everyone involved agrees on one thing: more research is needed to get to the bottom of the problem.

“We are pleased with the initial efforts and collaboration between Clemson and the pest control industry, but we also know that more work is needed to achieve our goal of 100 percent removal of SGAs from the island,” said Craig Weaver, Mayor the city of Kiawah. “Clemson’s initial research effort will help us determine the progress of these voluntary activities and can help the city identify other issues that may require attention.”

Jim Jordan, a city wildlife biologist, noted that the island’s bobcat population began to decline around 2017. “We’ve been tracking these animals for 20 years and haven’t seen this problem,” he said. “Of course something has changed, but we don’t know what it is.”

“It’s important for us to move forward and answer the question about the use of SGAs in the Kiawah ecosystem,” said Wright. “Ultimately, we can potentially reduce the use of SGAs in this ecosystem.

“We like the idea of ​​an integrated approach,” he said. “This naturally takes into account a lot of things that can influence the result. It’s not one-dimensional. “

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