A cloud of uncertainty

Updated August 28.

Three operators of an all-natural tick spray company donned khaki insect-shield pants and tucked the bottom hems into their socks. They wore shirts with their company name, ohDEER, like they do five or more days a week, readied their equipment, and pulled into a winding driveway in Oak Bluffs to the home of a year-round Island family. It was a Friday morning in mid-July.

The home, with a bright green front lawn and garden around the perimeter, was one of 100 others that the team at ohDEER treats for tick and deer mitigation each week, double the number of lawns they treated last year. The company also sprays at schools, daycares, and businesses. 

“We have five trucks going six, seven days a week. If weeks [had] eight days, [we’d] work eight days,” Elias Modesto, an ohDEER tick-spray operator for over a decade, said as he started the workday with two other operators, Isaac Pereira, a new employee this summer, and Álvaro Dalcin, ohDEER manager. 

The three workers rolled up their sleeves and started to pull a thin yellow hose, which stretches up to 400 feet from a work truck and is attached to a dispenser with a blend of castor oil, lemongrass, geraniol, sodium lauryl sulfate, and corn oil. Then, they each grabbed a spray nozzle and got to work.

They are one of many tick spray companies that have experienced a jump by the hundreds in their client lists this summer as anxieties about ticks continue to increase. But as the small arachnids and the conditions they can cause a human to develop become a major public health concern — getting the attention of both state and federal officials and repeatedly seen in coverage by national news outlets — there’s a smaller debate on the Island about what to do about them.

A new nonprofit, Tick Free MV, was launched over the winter to combat the spike in tick-borne conditions on the Island through an understanding and conversation about mitigating the population of deer, which are frequent carriers of ticks, while on-Island healthcare providers started tick-specific clinics and research centers to treat and study tick-borne conditions.

But in the meantime, tick spraying is becoming a more common way for Islanders and visitors alike to assuage immediate concerns about ticks, especially about developing the allergy to mammalian products called alpha-gal syndrome; it’s even been a common offering in short-term rental and Airbnb listings this summer.

Tick-spray workers are, for many homeowners, the first line of defense in the fight. And while some of them, like ohDEER, have operated for over a decade, the effects of all-natural tick sprays on the Island’s long-term ecology remain understudied.

And that lack of knowledge is giving conservationists and town health officials pause. 

What are tick sprays?

All-natural sprays are usually a blend of essential oils and occasionally mild soaps, and are used to deter ticks. All-natural sprays are exempt from federal, state, and local regulations, although on the Island, conservation commissions maintain some oversight on how closely spray is applied to wetlands and ponds. 

Synthetic sprays are primarily permethrin, and are used to kill ticks; permethrin is the treatment recommended by federal health agencies, and on the Island, it is usually used on clothes. 

Pesticides kill unwanted bugs, herbicides kill unwanted weeds, and insecticides kill unwanted insects. (Chemical tick sprays are broadly referred to as insecticides). All have been studied for their potential for human, animal, and ecological harm, and insecticides are known to have a negative long-term effect on the ecological balance of the land, though restrictions on use aren’t easily enforced. 

“The insect biodiversity of the Island is truly remarkable, so it is even more of a loss when it’s harmed by the broadcast spraying of insecticides,” Jeremy Houser, director of science and policy at the Vineyard Conservation Society, told The Times over email.

In the 1950s and ’60s, much of the country was sprayed from helicopters with an insecticide called DDT, which devastated insect biodiversity. Martha’s Vineyard was mostly spared from the insecticide, he said, though historical accounts show that there was some spraying then. 

Now Houser is concerned, along with local town officials and other conservationists, about the effect of spraying for ticks, even with all-natural components, on overall biodiversity, especially in regards to waterways. 

Education on all-natural tick sprays is lacking, aside from some firsthand knowledge by longer-running companies who use them and conservation groups aiming to tackle the issue. 

“Understandably, people are very interested in finding a way to spray their yard for ticks that’s less harmful to the environment. So we get a lot of questions, like ‘Is this spray better or worse than that one?’ ‘Are organic products and essential oils OK?’ People really do want to do the right thing, but they’re also scared,” Houser said.

The Times interviewed tick spray company operators and owners, conservationists, scientists, town officials, homeowners whose home was sprayed, and a Vermont ecologist, to try to answer those questions. 

Here’s what we found:

• Natural, essential oil-based tick sprays are not overwhelmingly impacting the environment in the short-term because they dissipate rather quickly, according to ongoing studies, but do deter about 70 percent of ticks where spraying occurs, and impact around 30 percent of pollinators and other bugs. 
• Chemical and synthetic sprays are regulated but under-studied locally, and restrictions are difficult to enforce. Their use is rising.
• The impact of both chemical and all-natural tick sprays on the Island’s long-term ecology and water quality is not fully understood.

Tick sprays and the people who operate them

Business has never been better for companies that mitigate ticks. And ohDEER is just one operation that has doubled its clientele this summer. Brewer Insect and Animal Spraying is another. Plus, landscaping companies and insect spray companies from off-Island have started operating here to meet the ever-growing demand.

Matthew Brewer, the owner of Brewer Insect and Animal Spraying, told The Times that he primarily sprays all-natural treatments but offers synthetic and chemical blends as well. 

“Some people have requested synthetic, not because the all-natural hasn’t been effective for them, but they just they just don’t want to take a chance,” Brewer said. 

Both Mario (“Eddie”) Spindola, owner of ohDEER, and Brewer said they support unraveling some of the unknowns regarding all-natural sprays. They’re meeting a need that exists, and they’re trying to do so through transparent practices, long-term efficacy observations, and a desire to address a public health concern. Brewer has worked for a few years, and Spindola’s OhDEER, starting in 2014, is one of the longest-running all-natural tick and deer deterrent companies on the Island.

“I saw the need on the Island for a safer, more conscious approach to the pest control that we normally see with the chemical applications,” Spindola said. “So families, landscapers, all the above, could enjoy their yards without poisoning the environment.” 

The homeowners of the Oak Bluffs property that ohDEER sprayed in mid-July, Bill and Robin Davies, have a similar outlook. Bill Davies is the owner of Davies Landscaping and Tree Services, and Robin is a teacher at the Edgartown School. They have a big dog who rolls around in the grass and occasionally munches on the bright green stems, and they used to find tons of ticks on him. Over the years, the couple has seen an influx of deer on their property, eating their flowers and meandering through their yard.

All-natural spraying through ohDEER, they said, has had a noticeable effect on the tick and deer population, and they still see bees, butterflies, and dragonflies. Both were seeking more answers regarding the long-term environmental effects of sprays, but without direction from the town, state, and federal government, the concern about tick-borne conditions is too great to go without mitigation at all. 

Brewer is involved in an ongoing local study regarding sprays, and Spindola said he’s hoping for more studies over time. Both company owners said all-natural sprays are the ones that are less studied, but chemical and synthetic blends have measured environmental effects. Brewer said that synthetic blends do kill pollinators. “When we spray any synthetics, we are cautious about it. We don’t spray anything that’s flowering,” Brewer said. 

Both business owners said they don’t wear personal protective equipment when working with all-natural sprays. Spindola’s workers are provided with permethrin-treated pants as their work uniform, and Brewer is a one-man operation. 

“If I’m doing a synthetic treatment, I will wear a mask,” Brewer said. “I’m very upfront with clients about exactly what’s in the product. It’s very safe for humans, pets, [and] children. But we’ve had great results tick-wise with it, so it’s kind of a win-win.”

The three workers for ohDEER at the Oak Bluffs property in July said they haven’t noticed any decrease in pollinators from using essential oil blends. Still, they said they’re careful not to spray bees, butterflies, dragonflies, or other insects. They also scatter a powder on the outskirts of yards that deter deer, which includes garlic and egg shells. Deer are the primary host of adult ticks, and on the Island, the population is extremely overabundant, at an average of 53 deer per square mile. The state’s target is 12 to 18 per square mile. 

“I’ve been living on this Island for 30 some years. I’ve never seen so many deer,” Modesto said. “We’re trying to keep everything in control.”

But even as all-natural sprays rise in use, many want a treatment that effectively kills ticks, not just deters them, and Spindola’s seen clients drop their all-natural product this summer because it doesn’t include permethrin.

“I would say there’s a small percentage of people that simply don’t care about what’s happening ecologically. They just are so fearful that they don’t want ticks in their yard. But I think most people, the majority of people, still want to be sensitive to protect pollinators,” Brewer said. 

BiodiversityWorks, a local conservation organization, has set out to study the effects of all-natural tick sprays on the Island’s ecology as the use rises. They’ve partnered with Brewer, evaluating properties before and after spraying is conducted.

“There really is a serious discussion to be had here with very, very high stakes. The more information that people have, the better off we’re going to be as a community as we try to sort these things out in a balanced way that maintains a diverse and resilient environment, while also affording people the protection that they need.”

Matt Pelikan, BiodiversityWorks

The organization is also looking into whether all-natural sprays kill pollinators, which are necessary to the environment, farming, and food production. Matthew Pelikan, community naturalist at BiodiversityWorks who is overseeing the project, said 80 properties are being surveyed. Their methodology is modeled after the first-ever study on the environmental effects of tick-sprays in New England by the Vermont Center for Ecostudies. 

Pelikan told The Times that the results from 2025 are analyzed, and the results suggest that all-natural “tick sprays are successful in reducing the number of ticks” but don’t eliminate them. 

Pelikan said insects, like ants, were seemingly unaffected by the spray, but spiders and hemiptera, which are insects like stinkbugs and cicadas, did seem to be impacted. 

“We also have a fair amount of anecdotal evidence of beating the bushes right after a treatment, and having moribund or dead insects fall out on bushes, which had been sprayed, and that did not happen with the control, untreated properties,” he said. Pelikan estimated that 30 to 40 percent of the insects within the immediate habitat on sprayed lawns were affected. 

The study by the Vermont Center for Ecostudies that Pelikan was inspired by had similar results. All-natural sprays were found to be less effective at reducing tick densities but were still found to affect pollinators. 

“A lot of the companies here say, ‘Hey, this essential oil-based stuff we’re spraying is better for the environment and less harmful to you, but it doesn’t work as effectively as synthetic pesticides, so we need to spray more often.’ And the ticks come back,” Jason Hill, a conservation biologist at the Vermont Center for Eco-Studies, said. “But our data line up with what the tick companies tell their customers around [in Vermont and New Hampshire] — that the spraying is temporary at reducing tick densities.”

Through the study, Hill found that all-natural sprays had an around 70 percent efficacy rate at reducing tick populations in the short term and with continued spraying, and pollinators were reduced by about 30 percent on properties that were treated.

Town officials look to the future

Tisbury board of health agent Drew Belsky, who is also on the Chilmark board of health, said all-natural tick sprays operate in a “gray area.” The sprays, which are usually a blend of essential oils and soap, are categorized by the Environmental Protection Agency (EPA) as FIFRA Section 25(b) products, which are exempt from federal regulations. “There’s currently no real oversight for this in any way, shape, or form that I’m aware of,” Belsky said.

But even though the EPA doesn’t regulate the all-natural blends, their effect on the environment and people is not necessarily harmless. For instance, one Chilmark resident submitted a complaint to the Chilmark board of health in June after the essential oil blend in an all-natural tick spray from ohDEER wafted from her neighbor’s property to her own, and she had an allergic reaction. And the possibility of tick sprays — chemical, synthetic blends, or all-natural — getting into private wells, soil, or the town water supply is another top concern. 

Chilmark board of health agent Anna McCaffrey said she’s looking into the possibility of regulating all-natural tick sprays as a result of this complaint and others like it that have come to her attention since. 

“We had a lot of phone calls from residents,” McCaffrey said. “It’s a problem. It’s a gap; 25b substances should be regulated.”

Companies that spray chemical and synthetic blends have to go through a permitting and regulatory process and require different certifications. McCaffrey submitted a letter to the Massachusetts Department of Agricultural Resources asking for guidance on all-natural spray enforcement, and Belsky drafted a regulation that could be used in the town going forward. 

“Commercial application of minimum-risk pesticide products in residential and environmentally sensitive areas may create odors, airborne particulates, drift, or chemical exposure conditions affecting neighboring residents,” the findings section of the proposed regulation for Chilmark states. 

While the town of Chilmark waits on a response from the state, tick spraying across the Island continues. 

“There really is a serious discussion to be had here with very, very high stakes,” Pelikan said. “The more information that people have, the better off we’re going to be as a community as we try to sort these things out in a balanced way that maintains a diverse and resilient environment, while also affording people the protection that they need.”

Editor’s note: Updated with a factual correction; Jeremy Houser said the Vineyard was mostly spared from a widespread insecticide spray called DDT many years ago. An abbreviated version of this story was published in print August 27. This is the full online version.