The Issue
Tick-borne illnesses have long been a serious public health concern on Martha’s Vineyard, originally because of the high incidence of Lyme and other diseases carried by the deer tick, and more recently compounded by the expanding Lone Star tick population and its associated Alpha-gal syndrome. In response, the island is now experiencing a proliferation of businesses offering outdoor insecticide spraying for ticks and mosquitoes. Unfortunately, while these companies are addressing an understandable desire for safety among their clients, the broadcast spraying of insecticides imposes significant harms on the natural environment without providing any clear benefit to public health.
“Synthetic” vs. “All Natural”
VCS is very concerned about the rapid growth of outdoor spraying of “all natural” or “organic” products for tick and mosquito control. These services have become popular largely because of the mistaken belief that they are safe for the environment and human health. While spraying companies seek to contrast these products with synthetic pesticides, the truth is that they are still pesticides, both by state definition and by common language: they kill (not just repel or deter) a broad spectrum of insects, arachnids, and other invertebrates. Further, they are not harmless to human health; exposure to all-natural sprays causes skin and respiratory irritation and serious allergic reactions among sensitive individuals.
All tick spraying, whether naturally-derived or synthetic:
Kills beneficial invertebrates. Despite the claims of some companies, all sprays that are effective in controlling ticks are broad-spectrum insecticides that don’t discriminate between their target (ticks and/or mosquitoes) and beneficial insects, spiders, and other arthropods in the area sprayed. Arthropods are the largest and most important group of animals on Earth; locally, they are the foundation of most island ecosystems, playing essential roles as pollinators, decomposers, herbivores, predators, and prey.
Impairs water quality. Tick sprays impact groundwater, streams, and ponds, both due to the normal process of running off or through the area treated, especially following rain, and due to accidental drift or overspray into non-treated areas. It is well-established that Permethrin and other pyrethroid-based products are highly toxic to fish, amphibians, and aquatic invertebrates. The impact of “all-natural” sprays on aquatic organisms is not well studied, but there is some evidence they are also harmful.
Harms people and pets. Spraying for ticks can cause skin, eye, or respiratory irritation, as well as serious allergic reactions, both for people and pets on the property being sprayed and their neighbors. Health effects may result from contact or inhalation, both during or after application. Those with specific sensitivities are at greater risk, as are children and pets due to their smaller body size and spending more time on treated lawns.
Gives a false sense of security: While tick spraying may temporarily reduce the number of ticks in the treated area (by about 60%, according to the best available long-term field study of tick spraying), it will never eliminate the need to protect ourselves through the tried-and-true methods that actually work: using personal repellent sprays on skin and/or clothing, and most important of all, careful and thorough tick checks. If spraying around the house is accompanied by any reduction at all in these personal protection measures, it is quite possible that the net result will be an increased risk of tick-borne illness.
“On properties that are routinely sprayed, I consistently observe far fewer insects. An occasional bee or damselfly may still appear, but the abundance, diversity and constant movement that characterize a healthy landscape are often diminished. That should give us pause.”
Cathy Verost, Local MV Landscaper
(click to read full letter to the editor)
Q&A
What is the best way to protect ourselves while also protecting our environment?
The most effective approach to reducing the risk of tick-borne illness is to focus on personal protection. Wear light colored socks and pants and tuck everything into everything, use personal repellent sprays (DEET or picaridin) on exposed skin, and, most important of all, do a thorough tick check upon heading indoors.
For extra protection, permethrin-treated clothing is an excellent option. Pre-treated items (socks, pants, shirts, and even specialized gaiters to wrap around legs) can be purchased, some of which can be washed numerous times before losing effectiveness. A less expensive option is to make your own using 0.5% permethrin spray (available locally and online). Make sure to follow all product instructions exactly, including only using it outdoors (away from bodies of water), wearing gloves, and letting items dry completely before wearing. Never apply wet permethrin directly to skin or anywhere cats may be.
Is there any way to reduce ticks on my property without harming the environment?
In truth, no effort to alter the outside environment can be as effective as personal protection. That said, there are helpful interventions that have minimal, or even beneficial, environmental impact. Keeping lawn areas mowed to 3.5 inches or less, removing leaf litter and pine needles from the edges, and creating a 3-foot-wide buffer strip of gravel (or another inhospitable surface) will keep ticks away from the areas most frequented by humans. (There are tradeoffs here with the Vineyard Lawn ethos of supporting biodiversity, but better to remove a small bit of habitat than to poison all the beneficial insects living there.)
Recognizing that this option is not available to many residents, the most powerful long-term intervention to reduce ticks both on one’s own property and island-wide is to encourage increased deer hunting. This can be done by giving permission to hunt on your land and/or your neighbors’, and by supporting local efforts to increase hunting by sharing the harvest.
What types of tick sprays are being used locally?
While there are a large and growing number of companies doing tick (and mosquito) spraying, our research has found that there are generally two types of services offered on the Vineyard. The “all-natural” sprays are usually a mix of essential oils (including geraniol, cedarwood oil, lemongrass oil, and castor oil), soaps like sodium lauryl sulfate (SLS), and inactive ingredients to help disperse the product. The synthetic (or traditional) sprays are usually pyrethroids (synthetic chemicals based on pyrethrin, a naturally occurring insecticide found in the Chrysanthemum flower), in particular permethrin and bifenthrin. Pyrethroids are neurotoxins that block the ability of nerve cells to communicate with muscles, effectively paralyzing and killing a wide diversity of arthropods, including ticks.
What about natural sprays that specifically target ticks? Are those safe for pollinators and other beneficial insects?
In short, broadcast spraying of any product, whether synthetic or naturally derived, that actually works to control ticks will kill significant numbers of nontarget insects, arachnids, and other invertebrates. Field studies of the impacts of yard spraying are beginning to explore the extent of the harm at the level of local populations. More fundamentally, there are no existing sprays that selectively target ticks (and there probably never will be) because of basic biology and chemistry, i.e. how the products work on a mechanistic level to achieve their effect. All sprays, synthetic or natural, target biochemical pathways that are broadly shared across diverse groups of arthropods
While spraying companies market their services as being targeted at ticks and/or mosquitoes and safe for pollinators, they are in fact using products labeled by the manufacturer as broad-spectrum insecticides. For example, the label of one of the most popular natural sprays being used on island announces that it effectively “eradicates” a wide variety of targeted pests, from mosquitoes and ticks to aphids, whiteflies, roaches, ants, and others. Scientifically, there are two stark contradictions between this and the claim that the product is safe for pollinators. First, this is an incredibly diverse group taxonomically, encompassing a wide range of anatomy, physiology, life history and behavior. Ticks and mosquitoes are far less similar to each other than they are to spiders and bees, respectively. Second, the list of targeted pests actually includes ants – close relatives of bees, but also vitally important pollinators in their own right.
What about sprays that repel ticks instead of killing them?
While there is some evidence that certain essential oils used in natural tick sprays may have some repellent properties on ticks (and other invertebrates), the primary effect of any product used to control ticks is lethal. The most common killing mechanism of natural oils and soaps is suffocation through blocking spiracles, a breathing apparatus widely shared across insects and arachnids. Depending on the specific oil used, other mechanisms of action may also contribute to the overall effectiveness; for example, cedar oil shows some ability to dissolve insect exoskeletons.
Are these products regulated?
The responsibility for regulating pesticides was granted to the EPA through the 1996 Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). Like other traditional pesticides, pyrethroids must go through EPA’s rigorous registration process (testing, labeling, review, etc.) before being marketed. This is part of why the mechanisms of action, and the environmental risks associated with them, are so well understood.
In contrast, many natural oils, including those used in natural tick sprays, have been exempted from these registration requirements by the EPA under FIFRA Section 25(b). These products have been classified as “minimum risk pesticides” by the EPA because of their presumed low toxicity to humans and other mammals; however, they remain non-selective insecticides and may cause allergic and other reactions in humans and pets.
Are the spraying companies themselves regulated? Is there any licensing required?
The state Pesticide Board, operating under the Mass Department of Agricultural Resources (MDAR), oversees statewide regulation of pesticide use. State law requires anyone who applies pesticides in public areas or private places used for human habitation must be licensed following passage of a written exam administered by MDAR.
What about local regulation? Can towns do anything to limit spraying?
The rapid increase in spraying has led to calls on towns to do something to limit the impacts on neighbors and the environment. Massachusetts law grants the authority to regulate pesticides to MDAR, and crucially, it preempts (i.e. prohibits) in most circumstances any additional regulation by localities.
Notably, in 2026 the town of Chilmark, in response to residents’ complaints regarding health impacts caused by repeated “natural” spraying in their neighborhood, developed a draft “nuisance regulation” to address the issue. Deliberately crafted to avoid the areas of authority preempted by MDAR (e.g., what can be sprayed, how much, and how often), the new rules merely called for advance notification of neighbors, better record-keeping, and taking efforts to reduce drift and runoff into sensitive areas. Surprisingly, when the Board of Health shared the draft with MDAR for comment, the state agency responded that the Town had no authority to do any of it. Worse, the response from MDAR contained within it a startling Catch-22 regarding natural sprays: 25(b) products are not regulated because of the EPA’s decision to not register them; however, because 25(b) products are still classified as pesticides, MDAR has the sole authority to regulate them within Massachusetts. By simultaneously claiming sole authority to regulate and an inability to do so, MDAR has decided it is impossible for anyone to regulate this large class of products.
Another possible avenue for local limits on spraying may be for town Conservation Commissions to add spraying to the list of modifications to the environment that need approval if done within a wetland buffer zone. Check back for updates on this and/or any other local efforts to limit the impacts of outdoor spraying.
Does tick spraying actually reduce the risk of tick-borne illness?
There are limited comprehensive studies into the effectiveness of pesticides in controlling ticks or reducing the risk of tick-borne illness. Two that stand out are the ongoing “Backyard Tick Project” by the Vermont Center for Ecostudies, and the five-year neighborhood tick study conducted by the Cary Institute of Ecosystem Studies.
The Vermont Center for Ecostudies project found that pesticide sprays reduced numbers of ticks and non-target invertebrates, including pollinators and other beneficial insects. The effects on tick density were short-lived, lasting for a few weeks, and there was no relationship between a property’s history of spraying and its current tick density.
The Cary Institute’s tick project focused on the effectiveness of two pesticide treatments on reducing tick-borne illness across five years and 24 neighborhoods in New York. The study determined that “Tick Control System” mammal traps (baited boxes treated with fipronil, an idea similar to tick tubes) were effective in reducing tick numbers, while the broadcast spraying of Met52 (a relatively new fungus-based insecticide) was not. More important, neither treatment had any effect on reducing tick-borne illness in the community.
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