Field plate · Ixodes scapularis
Blacklegged (deer) tick
Pinhead nymphs in late spring, sesame-seed adults in autumn — and the tick that carries Lyme disease in Erie County.
Plate 20 of 28. Drawn in profile to the identification marks named below; the scale rule is a drawing convention — sizes are given in the text.
Identification marks
Adults about 2–3 mm unfed, reddish-brown with a dark shield and dark legs; the female's shield covers only the front half. Nymphs in May–July are the size of a poppy seed. Engorged females swell grey and bean-like.
Look-alikes it is confused with
American dog tick (larger, with white markings on the shield, common on dogs and in grassy fields) and lone star tick (expanding in Pennsylvania; female has a single white spot). Save the tick, note the date — identification matters to a clinician.
Where it hides in a house
Not a house pest: leaf litter, woodland edges, stone walls, woodpiles, and the unmown margin where lawn meets woods — exactly the edge that Presque Isle, Asbury Woods, and most Erie yards provide. It quests on low vegetation and rides in on people, dogs, and deer.
Health & property risk, stated plainly
The most consequential pest on this page set. Blacklegged ticks in Pennsylvania transmit Lyme disease, and can also carry anaplasmosis, babesiosis, and Powassan virus. Risk management is personal and veterinary — tick checks, prompt removal, and medical advice for symptoms or a spreading rash — not a spraying question.
What actually works
Habitat first: mow, clear leaf litter, move woodpiles and play sets away from the woods edge, and consider a gravel or mulch barrier at the lawn margin. On people: repellent used as labeled, long socks in season, a full tick check and shower after woods and yard work, and clothes in a hot dryer. Dogs need a veterinary tick program.
What doesn't
Believing a yard treatment is either compulsory or a guarantee — blanket yard spraying is a choice with non-target costs, often aimed at the wrong month, and no treatment removes the need for tick checks.
Removing a tick, and the days after
Grasp it with fine-tipped tweezers as close to the skin as you can, and pull upward with steady pressure — no twisting, no burning, no oil or nail polish, which only delay removal. Clean the bite and your hands, then save the tick in a sealed container with the date on it: species identification is what makes any later illness conversation precise. In the following days and weeks, watch for the expanding bull’s-eye rash of Lyme disease, fever, or joint aches, and seek care promptly if they appear — early Lyme is treated far more easily than late. The desk repeats the plate’s caution: a skin lesion is a matter for a clinician, not for a field guide.
When to call a licensed pro
Call a pro — or rather, your clinician — for any tick bite followed by fever or an expanding rash, and a veterinarian for pets. Landscape-scale tick work is a separate, deliberate decision, not a reflex.