Fall Is Peak Adult Tick Season in Connecticut

Most people in Connecticut think tick season ends around Labor Day. The kids go back to school, the shorts go in a drawer, and the tick checks quietly stop.

That's exactly backwards. October is when adult deer ticks come out.

The Connecticut Agricultural Experiment Station's own life-cycle chart puts adult blacklegged tick activity at October and November, with a second peak the following March and April. Dr. Goudarz Molaei, who runs the state's tick testing lab in New Haven, has described the two busiest stretches for tick submissions as May to June, or October to November.

So there are two tick seasons here, not one. You just hear about the summer one.

The fall one matters, because the October tick is a different proposition from the June one: bigger, easier to spot, and considerably more likely to be carrying something.

The Connecticut tick calendar

The blacklegged tick — the deer tick, the one that carries Lyme — takes two years to complete its life cycle. Each stage has its own season, and they don't overlap much.

Here's the schedule, from the CAES Tick Management Handbook (Bulletin 1010) by Dr. Kirby Stafford:

The detail that catches most people out is the line about winter. Adult blacklegged ticks do not hibernate. The CAES handbook is blunt about it: they stay active through the winter “during periods of warm weather.” The CDC puts the same point in terms of the thermometer — adults may be looking for a host any time winter temperatures are above freezing. UConn Extension sets a slightly more conservative bar, noting ticks can be active whenever temperatures are over roughly 50°F.

Connecticut gets plenty of 50-degree days in November. We get them in January some years. There's no date on the calendar where you can safely stop looking.

The fall ticks are the infected ones

This is the part worth sitting with.

In 2025, CAES dragged 40 sites across all eight Connecticut counties and tested a portion of what it collected. In the 2025 results, they screened 927 adult female blacklegged ticks and 733 nymphs. On the two numbers that matter most, the gap is wide:

Four out of five adult female deer ticks in Connecticut are carrying at least one pathogen. More than half carry the Lyme bacterium.

The reason is simple arithmetic. Molaei explained it in a CAES press release this spring: adult ticks “often have higher infection rates because they have had two chances to acquire disease agents during their juvenile stages.” A nymph has fed once. An adult has fed twice — usually on white-footed mice, which are the main reservoir for the Lyme bacterium in this state. Two meals, two lotteries.

One genuine piece of good news: adults are sesame-seed sized, not poppy-seed sized, so you have a real chance of finding one in time. The nymph that got you in June was the size of a comma in this sentence. The adult that tries in October is findable.

Worth knowing what the summer numbers look like too — our tick risk by county guide breaks the same survey down by where you live. CAES put New London County highest for adult density, at 81 per acre, and Fairfield County highest for Lyme in adult females, at 68%.

Where Connecticut homeowners actually meet them

Fall tick exposure doesn't look like summer tick exposure. In July you get bitten hiking at Sleeping Giant or Devil's Hopyard. In October you get bitten in your own yard, doing chores.

Raking and moving leaves. This is the big one. Leaf litter along the edge of your lawn is prime tick habitat — it holds the humidity they need. In October you handle all of it by hand, often kneeling in it, usually in a fleece ticks can grip. UConn Extension recommends removing leaves during the fall season, and that advice is sound. Just do it knowing what's in there.

The woodpile. If you burn wood, you're moving a stack that has sat at the treeline since spring. CAES recommends keeping woodpiles away from the house because of rodents — and the ticks follow the rodents.

Stone walls. Every old field wall in Connecticut is a mouse hotel, and mice are what make ticks infectious. The CAES control fact sheet recommends you clean up stone walls near the home that provide shelter for mice and chipmunks. Not demolish them — clear the brush and debris that pile up against them.

The dog. Dogs keep going out in November, straight through the edge habitat you're avoiding.

Hunting, and anyone walking state land. Connecticut's archery deer season runs Sept. 15 through Dec. 31 on private land, with firearms season Nov. 18 to Dec. 8 and muzzleloader through late December. Months of people sitting still in the woods exactly when adult ticks are questing — in the habitat of the white-tailed deer, which CAES calls “the principal host for the adult stage of the tick.”

Three things that cost nothing

None of this requires a contract, a technician, or a product.

1. Put your yard clothes straight in the dryer. Not the washer — the dryer. UConn Extension notes that drying clothes at high temperature, even without washing them first, is very effective. Ticks survive a wash cycle better than you'd think; they don't survive high heat. Twenty minutes on high after raking is the cheapest habit there is.

2. Keep the barrier, if you already have one. CAES recommends a dry wood chip, bark, mulch or gravel barrier between woods and lawn, plus keeping grass mowed — UConn Extension suggests no taller than three inches. A mulch bed along your treeline already is that barrier; it just needs to stay dry and clear. The same CAES fact sheet notes that removing Japanese barberry, which is all over Connecticut, measurably reduces tick abundance. Work, but not money.

3. Mail the tick to New Haven — the state tests it free. This is the most underused service in Connecticut. CAES runs a tick testing laboratory and states plainly that there is no cost for tick identification or testing. Keep the tick dry in a crush-proof container or sealed bag — no tape, no alcohol, no glass — fill out the CAES submission form, and mail it or drop it off at the Tick Testing Laboratory, Jenkins-Waggoner Building, 123 Huntington Street, New Haven, CT 06511.

Removal, per UConn Extension: clean tweezers, grasp close to the skin, pull straight up and out. No burning, no Vaseline. Then wash the bite and save the tick.

Is a fall treatment worth paying for?

Sometimes. The honest version:

There's real logic to a fall application, and pest control companies didn't invent it. The CAES tick control fact sheet describes fall applications as targeting adult ticks, with early spring as the substitute if no fall treatment happens. But the timing that fact sheet pushes hardest is mid-May to early June, aimed at nymphs — the application with the clearest rationale, because nymphs cause most Lyme cases.

So a fall spray is a legitimate second window, not the main event. It makes more sense if your property backs onto woods, you've had repeated finds on people or pets this year, or you're in a higher-density part of the state. Less sense if your lot is open and sunny, you rarely find ticks, or you've already done the free work above.

Two things nobody should promise you. No yard treatment eliminates ticks from a property — they arrive on deer and mice, which don't respect property lines, and reinfestation from the edge is normal. And no treatment prevents tick-borne illness; it reduces how many ticks are in a treated area. Tick checks and prompt removal do more of the work than any spray.

We have a fuller breakdown of that judgment call in are tick treatments worth it?, including when the free steps are genuinely enough.

To be clear about what we are: DuckTheBugs isn't a pest control company. We don't spray, inspect, treat, or hold a pesticide licence. If you want a pro, we'll match you with licensed local companies at no cost — and if you don't, that's a perfectly good outcome too.