Several species of red or reddish bugs are common across Maryland, and what you’re seeing depends on the size, location, and time of year. The most likely culprits are clover mites (tiny, pinhead-sized specks on windowsills or siding), boxelder bug nymphs (pea-sized and clustered on trees or sunny walls), spotted lanternfly nymphs (red with white spots, found on plants in summer), or chiggers (invisible to the naked eye, known only by their itchy bites). Here’s how to tell them apart and what to do about each one.
Clover Mites: Tiny Red Specks Near Windows
Clover mites are the most common “tiny red bug” people find in and around Maryland homes. They’re smaller than a pinhead, with reddish-brown, globe-shaped bodies and eight yellowish legs. Their most distinctive feature is a pair of front legs roughly twice as long as the others, held straight out in front of the body like antennae. You’ll often notice them on windowsills, siding, or concrete surfaces, especially in spring and fall.
These mites live primarily in lawns, where they feed on grasses and other plants without causing noticeable damage. They migrate toward buildings when outdoor conditions become unfavorable, usually when hot summer weather arrives or cold weather sets in. Population pressure can also push them indoors in large numbers. If you’ve seen dozens or hundreds of nearly invisible red dots crawling across a sunny window frame, you’re almost certainly looking at clover mites.
Clover mites do not bite people, carry diseases, or damage food or furnishings. The only real problem they cause is a reddish stain if you crush them, so avoid wiping them off surfaces with pressure. Instead, vacuum them up or use a damp cloth gently. To keep them from entering your home, maintain an 18- to 24-inch strip of bare gravel or mulch between your lawn and your foundation. This plant-free buffer removes their food source right next to the building and discourages migration indoors.
Boxelder Bug Nymphs: Red and Black Clusters on Trees
If the red bugs you’re seeing are larger, roughly the size of a small pea, and clustered in groups on tree trunks, sunny walls, or porches, they’re likely boxelder bug nymphs. These immature bugs have bright red abdomens with black legs and short black wing pads. As they mature through the summer, their wings grow longer and eventually cover the red abdomen entirely, producing the familiar black-and-red-striped adult.
Boxelder bugs feed on the leaves, twigs, and seeds of boxelder trees and sometimes other maples. Female boxelder trees, which produce winged seed pods, tend to attract the largest populations. In October in central Maryland, nymphs and adults gather in large masses on tree trunks near the ground and on landscape mulch. They then seek sunny, light-colored surfaces, showing a particular preference for white siding on south-facing walls.
As temperatures drop, adults look for sheltered places to hibernate, including rock piles, leaf litter, and cracks in buildings. They can find their way indoors through small gaps and become a nuisance on warm winter days when they wake up and wander around the house. They don’t bite, don’t damage structures, and don’t reproduce indoors. Sealing cracks around windows, doors, and utility entry points is the most effective way to keep them out.
Spotted Lanternfly Nymphs: Red With White Spots
Maryland residents are increasingly encountering bright red bugs with black and white spots on trees and garden plants from July through September. These are fourth-instar spotted lanternfly nymphs, the final juvenile stage before the insect becomes a winged adult. They’re roughly half an inch long and unmistakable: vivid red bodies covered in distinct white spots and black patches.
Spotted lanternflies are an invasive species, and all 23 Maryland counties plus Baltimore City are currently under a quarantine order from the state Department of Agriculture. The insects have piercing, straw-like mouthparts and feed on sap from a wide range of plants, including grapes, hops, apples, stone fruits, maples, and walnuts. In residential gardens, though, they’re mainly a nuisance pest and haven’t been shown to significantly damage otherwise healthy ornamental plants.
If you spot them, the Maryland Department of Agriculture asks all residents to report sightings. Resist the urge to spray pesticides or home remedies. According to the University of Maryland Extension, spraying can do more harm than good in residential settings, killing beneficial insects without meaningfully reducing lanternfly populations. Squishing individual nymphs and scraping egg masses off trees (the gray, mud-like patches found on trunks and outdoor surfaces from fall through spring) are more targeted approaches.
Chiggers: The Red Bug You Can’t See
Chiggers are a different category entirely. You won’t spot these mites crawling around your home or garden because they’re nearly invisible. Larvae measure less than 0.4 millimeters across, far too small to notice on your skin. You’ll only know they were there when intensely itchy red welts appear hours later.
Only the larval stage bites humans. Contrary to popular belief, chiggers don’t burrow into your skin or suck blood. Instead, they attach at hair follicles and feed on digested skin cells for up to three days. They gravitate toward spots where clothing fits tightly: ankles, waistbands, armpits, and behind the knees. Itching typically begins 3 to 6 hours after attachment and can persist for up to two weeks. Scratching often removes the mite itself but can lead to secondary skin infections.
In Maryland, chiggers are most active from late spring through early fall. They prefer vegetation transition zones: the edges where forest meets grass, margins of swamps, brush thickets, and even well-maintained lawns and golf courses. If you spend time in these areas, wearing long pants tucked into socks and applying insect repellent to skin and clothing are the most reliable defenses. Showering soon after outdoor activity and washing clothes in hot water can also remove larvae before they attach.
Concrete Mites: Red Dots on Pavement
If you’re seeing small red bugs on sidewalks, patios, driveways, or the exterior walls of your home, you may be looking at concrete mites (sometimes called sidewalk mites). These are larger than clover mites, measuring 1 to 2 millimeters, and are bright red. They have a visible gap between the second and third pairs of legs and one or two pairs of eyes set far back on the body.
Concrete mites are predatory, feeding on other tiny invertebrates and their eggs rather than on plants. They’re harmless to people, pets, and structures. They tend to show up on warm, sunny days in spring and are most noticeable on light-colored surfaces like concrete and masonry. No treatment is needed; they typically disappear on their own as temperatures climb.
How to Tell Them Apart Quickly
- Smaller than a pinhead, near windows or on siding: Clover mite. Look for the extra-long front legs.
- 1-2 mm, on concrete or pavement: Concrete mite. Bright red, active on sunny days.
- Pea-sized, red and black, clustered on trees or walls: Boxelder bug nymph. Most visible in fall.
- Half-inch, red with white spots, on plants: Spotted lanternfly nymph. Report to Maryland Department of Agriculture.
- Invisible, but you have itchy welts at your ankles or waistline: Chigger bites. Itching starts hours after outdoor activity.
Of all these species, only chiggers bite. Clover mites, concrete mites, boxelder bug nymphs, and spotted lanternfly nymphs are harmless to people. The most important step for any of these bugs is correct identification, since each one has a different habitat, seasonal pattern, and set of management options.