How to Control Pests on Your Boat

We humans aren’t the only species that loves boating: Insects, spiders and even rodents do, too—and once they invite themselves aboard, getting rid of them can be a real challenge. Most bugs breed like rabbits: A few sneak aboard, and before you know it there’s a million of them crawling around in your boat’s deepest, darkest recesses. Mice and, in extreme invasions, rats are just as bad. And cockroaches have been around since the dinosaurs, so getting rid of them is never easy.

All these critters, like the rest of us, like being warm, well-fed and safe—and there are plenty of nooks on board that offer all three, spots so far beyond our reach in the bilge, the galley, behind joinery and in the engine room that we can only imagine what’s living there. Rousting out four-, six- or eight-legged squatters requires expertise, determination, and sometimes exotic weaponry. Last century’s toxic bug killers don’t make it; today there are better, safer, more environmentally friendly methods. If you’re lucky, you can DIY pest remove using off-the-shelf products, but in most cases a faster, surer path to a bug-free future is hiring a specialist who’s experienced with marine extermination.

If you want to find bugs, boats and people involved with both, where better to look than Florida The Sunshine State has critters of all types anxious to move aboard, and exterminators dedicated to getting rid of them. Todd Stebleton and his wife, Natalie, own Universal Pest Control in Ormond Beach. Pest control changes with your latitude, said Todd—boaters in the North have a different assortment of bugs to deal with than those down South. For example, “Palmetto bugs [big cockroaches] are on board boats all over the South. Boat owners usually reach for sprays and bug bombs to fight roaches, but they do more harm than good.” Sprays just send the roaches deeper into the boat, and foggers contaminate everything. Instead, said Stebleton, enclosed bait stations (roaches are tempted by the poison inside, return to their nest and die; other roaches cannibalize the corpse and die themselves) work a lot better on boats, and can be placed anywhere. But, he warned, “Commercial roach baits often have holes too small for a palmetto bug to fit into. So in the South, be sure to get bait stations with big holes.”

There’s also a termite problem in the South, said Stebleton, with large populations in Florida. They often infest wooden structures in historic areas, typically near the water. “Termites can swarm, get aboard a boat and set up a home in any wood on board.” (Even many fiberglass and metal boats have teak decks, wooden trim abovedecks, lots of wooden joinery belowdecks—plenty of opportunity for termites to set up a colony.) The only way to deal with termites, said Stebleton, is fumigation: Once the boat is covered with a tarp around the hull—it’s not as tight as shrink-wrapping; he uses a commercial tarp similar to the blue-poly tarps used by many boaters—gas is pumped under the tarp to kill the termites. (The same procedure is used for bedbugs, a growing problem aboard Florida boats.) Fumigation takes 24 hours, with another 24 hours for ventilation after the tent’s removed, so it’s at least a two-day process, or three-days depending on how long it takes to create the tent.

Respect the Protocols

Kevin Grindell is a pest-control expert at NozzleNolen, a family-owned company in West Palm Beach. Grindell often has to exterminate termites and bedbugs on larger yachts too big to cover. Instead, he seals all the deck openings to turn the boat itself into a “tent” before flooding the belowdecks with gas. But, warned Grindell, tenting doesn’t provide long-term protection: It only kills the bugs that are already there; another swarm of termites can fly onto your boat the next day, or a new family of bedbugs can come aboard with the next party of guests. “So get a renewable warranty in case the termites come back,” he advised.

Each variety of pest has its own method of treatment, said Grindell, but getting rid of any pests on board boats takes special skills, and can sometimes involve extreme measures. Working with an exterminator who knows his way around boats will make the process go smoother. “When you’re dealing with yachts, you’ve got to solve the problem fast,” said Grindell, especially aboard charter boats where down time costs big money. And the exterminator must be “mindful that the yacht might be someone’s home—there’s often crew living aboard.” An exterminator who can “respect the protocols,” who knows boats, and who knows the language can put the crew, and/or the owner, at ease. There may be other things going on, too—repairs, refitting, charter guests leaving and arriving, etc.—so find an exterminator who’s comfortable working in this environment.

And, added Stebleton, “Check that the pest control company you choose has insurance, and that they have all the required paperwork filed with the marina or boatyard office. Otherwise, they might not be allowed to work on your boat.”

Most infestations don’t require extreme remedies like fumigation, so you might want to try dealing with the pests using off-the-shelf products. The first step is to identify the invaders; here’s where a pro can really help. Stebleton said that once he knows the problem, he will teach his client how to solve it, and the best materials to use. If you can trap one of the critters and photograph it, or send it to the exterminator, he can often tell you what products and procedures to use.

You can buy effective products over the counter, said Grindell, but you have to use them properly, and place them where they’ll be most effective but least noticeable by crew and guests. Sometimes gel bait or pesticide dust squeezed into cracks and crevices around a countertop works better than bait stations, for example, but both can be negated when a crewmember cleans the countertop—the cleaning solution contaminates the bait. And some poison sprays will also cancel out baits. “Just slinging bug spray all over the place isn’t the thing to do,” Grindell said. “The only thing to spray openly is insect growth regulator; it’s birth control for bugs and makes baits more effective.”

Keep Them Ashore

Keeping the invaders ashore in the first place is your best defense. Some of them fly, so this can be problematic, but an ounce of prevention is worth way more than a pound of cure. Don’t let your boat become a spa for bugs. Keep everything clean, especially of organic material; insects aren’t picky eaters, and can survive on almost anything. Don’t leave the galley messy, clean up crumbs, dump the trash frequently, and keep all foodstuffs in sealed, non-edible containers. Scrub the cockpit after picnics to flush away bits of food and spilled soda and beer.

Cardboard boxes are gourmet fare for cockroaches, and they can live in corrugated materials, or lay their eggs there, so leave cardboard on the dock. Transfer the contents to plastic containers and take the boxes to the dumpster. Basically, remove from the boat whatever you think would make an insect happy. (FYI, bugs and insects aren’t the same; all bugs are insects, but not all insects are bugs. And spiders are something completely different.)

Clean up thoroughly after shoreside cookouts near your boat. Take uneaten food to the distant dumpster rather than leaving it in a nearby garbage can where rats, mice, and maybe raccoons will see it as a smorgasbord. A well-fed varmint looking for a place to sleep it off can scamper aboard and take up residence in a matter of minutes. And once Mr. Mouse discovers how comfortable your boat is, he’ll be loath to leave. Spraying your docklines, fenders, side decks and even the dock itself with environmentally safe rodent repellent might keep them off, but you have to renew it frequently. Peppermint oil is the anti-mouse choice of many pest-control experts—apparently mice can’t stand the smell. Some folks say dryer sheets work, too, as do mothballs—put them in perforated plastic bags and stash them in warm, dark places mice might want to homestead. (Think like a mouse.)

Mice and rats will also chew on anything available—chewing maintains their teeth, preventing them from growing too long. Because of this, rodents can quickly destroy wiring insulation, leading to short circuits and maybe fires. They’ve also been known to chew through hoses, causing leaks and worse. And don’t ask what they can do to fine wood joinery. Bottom line is, keep rodents ashore, and your boating life will be easier. Getting rid of mammals is a lot more complex than poisoning insects—in the first place, you don’t want them to die in the far reaches of the bilge, where their decomposing corpses will soon start to smell something awful. Call an expert if you discover them living aboard, before they do serious damage.

What About Spiders?

In my New England neck of the woods, spiders are frequent on board pests, and are seemingly impossible to get rid of: Shoo them away one day—some folks vacuum them up—and they’re back the next. Spiders aren’t insects, but arachnids, not that it makes much difference once a horde of them take up residence on your boat. However, unlike many insects (and I’m looking at you, cockroaches) most spiders aren’t harmful, but actually helpful critters: They eat annoying insects like gnats and mosquitoes, so there are better remedies than executing them en masse.

Spiders don’t take bait, said Todd Stebleton, so getting rid of them means constant spraying, not the best thing for the environment. If you can get rid of the bugs they feed on, you’ll ultimately get rid of the spiders. Yellow-tinted lights attract fewer bugs than blue-tinted, so changing dock lighting is a start too, he advised. Spiders have delicate senses of smell and can be chased away by spraying with a strong-smelling solution comprised of vinegar, citrus, or an essential oil; peppermint oil—the same solution you use to keep mice away—is a favorite of many pest-control experts. Starbrite makes a peppermint-oil-based spider repellent called Spider Away, that’s formulated for docks and boathouses. Or you can mix your own repellent using one of the thousand recipes available on the Internet.

If you go boating, eventually you’ll find stowaways on board, insect, mammal or arachnid. Who can blame them for enjoying time on boats, like we all do? Don’t let the critters ruin your seagoing fun: Bugs and rodents can be an annoyance, but getting rid of them isn’t rocket science. Pay a visit to the pest-control section of your hardware store, or call a local exterminator who knows his/her way around boats, and send the stowaways back where they belong.

The Admirable Cockroach

For most of us, the most repellent insect is the cockroach, and it’s also one of the potentially most harmful: Roaches carry germs that can spread disease and trigger allergic reactions in some folks. And they’re pretty disgusting to look at, especially when you see dozens of them huddled together in a wriggling mass. On the other hand, they’re interesting critters if you can get past their creepiness.

There are more than 4,000 species of cockroach, although the ones most common aboard are the German, Oriental, Brown-Banded and American varieties. (There’s one South American species that’s six inches long.) “Palmetto bug” is what most Southern folks call the American cockroach, which actually comes from Africa. They can grow to more than two inches long and can fly. Up north, where there are no palmettos, they’re often called “water bugs.” Down South, palmetto bugs can be found by the horrifying thousands at the sheltered spot where fronds sprout from the trunks of palmetto trees. So if you have them on your property, one great way to get rid of them is have a professional shave your trees. There’s also an Oriental cockroach that looks much the same to the non-expert, and is also called a palmetto bug. And just to make things more confusing, there’s the true water bug, which looks like a cockroach, but isn’t. It lives in fresh water, grows up to 4 inches long, and can give you a nasty bite. (Roaches don’t bite.) You need an entomologist to keep all this straight.

Fossils suggest cockroaches have been around for at least 100 million years, so they must be doing something right. They could be much older: Some experts think it’s more like 300 million years. Whatever, when the last T-Rex ate his/her last meal, roaches were there to feast on the leftovers—they survived the asteroid that finished the dinosaurs 66 million years ago. Roaches can live without food for a month but will die in a week or so without water, so eliminating their supply of water will eradicate them—not so easy to do aboard a boat, where there’s often plenty of good drinking in the bilge. Boats are generally pretty clean, so if you have roaches on board, chances are you brought them aboard inadvertently. Fortunately, they are suckers for poisonous roach baits. Power & Motoryacht’s Charleston-based Senior Editor Chris Dixon swears by a Syngenta bait called Advion that rid his camper, house and a friend’s motorsailer of palmetto bugs when nothing else would.

This article originally appeared in the March 2024 issue of Power & Motoryacht magazine.

Source: https://www.powerandmotoryacht.com/maintenance/how-to-control-pests-on-your-boat