Wasps and Hornets Around a Maine House

Almost every stinging insect that builds a nest on a Maine house belongs to one family, the Vespidae, and UMaine Cooperative Extension sums up their year in two sentences: a single fertilized queen starts the colony each spring, and it keeps growing through the summer as workers hatch, peaking in mid to late summer. Everything practical about wasps follows from that cycle. A nest is smallest and easiest to deal with in May, largest and most defensive in August, and finished by the first hard frosts.

Telling them apart

The detail that saves most confusion: an enclosed gray paper ball is either a bald-faced hornet or an aerial yellowjacket, and the open comb you can see into is a paper wasp. A hole in the lawn with traffic in and out is almost always yellowjackets.

The Maine year, from queen to frost

Spring. Mated queens that spent the winter in sheltered spots come out early, according to the Maine State Apiarist’s yellowjacket fact sheet, and each one picks a site and builds a small starter nest on her own. Until her first daughters hatch, she is the only wasp in it.

Early summer. The first workers take over building and foraging, and the queen does nothing but lay eggs. Growth from here is fast.

Late summer. Colonies reach their peak, and by the Apiarist’s account the wasps are still increasing as autumn begins. Natural food runs short at the same time, which is why the late-August picnic table suddenly attracts them.

Autumn. The colony raises new queens, they mate and go off to overwinter, and the Apiarist notes that in a normal year the old colony dies after the first hard frost. The Maine School IPM Program’s fact sheet adds that nests are not reused the following season.

When a nest can be left alone

UMaine Extension’s management guidance begins with restraint: hornet, wasp and yellowjacket nests should not be disturbed unless they pose a risk. The Maine School IPM Program — writing about schoolyards, where children are about all day — reaches the same conclusion, that nests located where they can be avoided do not need to be treated. These insects take caterpillars and other pests off the garden, and a nest in a corner of the property nobody uses is doing more good than harm.

Our default with a low-risk nest is to say so. The nests that do need dealing with are the ones beside a door, over a deck, inside the wall of a bedroom, in a play area or in a lawn that gets mown — and any nest at all where someone in the household has a sting allergy.

Stings and allergy

For most people a sting is painful and nothing more. For some it is a medical emergency. The Maine School IPM Program’s fact sheet notes that as many as 40 allergic individuals die from stings in the U.S. every year, and UMaine Extension describes stings as potentially life-threatening to people with allergies. The CDC’s NIOSH guidance for outdoor workers says people with a known severe allergy should carry an epinephrine auto-injector and wear medical identification.

For an ordinary sting, NIOSH’s first-aid steps are simple: wash the site with soap and water, remove a stinger by wiping or scraping rather than squeezing, apply ice for the swelling, and do not scratch. The same guidance describes anaphylaxis as a severe, potentially life-threatening reaction that needs immediate emergency care, so any sign of it after a sting is a 911 call, not a wait-and-see.

What you can safely do yourself

Most of the useful work is prevention, and it is free.

• Look early. UMaine Extension notes that nuisance nests are most easily removed in early spring, before the colony has had a chance to grow. A walk round the eaves, the deck rail and the shed door once a week in May finds nests while they are tiny.
• Close the cavities. The Maine IPM Council’s yellowjacket tip sheet recommends sealing openings in outside walls, fences, pipes and meter boxes so wasps cannot nest inside them. The Maine School IPM Program adds the exception: never seal the entrance of an active nest until the colony is dead.
• Manage the food. Covered drinks, covered pet food, and bins with tight lids that are emptied and rinsed often cut the late-summer foraging pressure more than any spray.
• Leave ground and wall nests alone. The IPM Council’s tip sheet says removing underground or inaccessible nests is not practical for a homeowner, and that stings are likely while spraying — and possible the next day from wasps that were only partly knocked down.

Why ground nests are the dangerous ones

A yellowjacket colony in a bank or under a lawn reacts to vibration through the soil, so the first warning is usually the mower stalling in a cloud of wasps. The Maine School IPM fact sheet points out that ground nests often have bare earth around the entrance and can have secondary entrances some distance from the main one, which is exactly why a single blast of retail spray into one hole so often goes wrong. If you find one, flag it from a distance, keep children and dogs off that part of the yard, and leave it for after dark and for someone with the right equipment.

Honey bees and bumble bees are different

Not everything that stings is a pest. The Maine School IPM Program describes bees as generally mild-mannered and important pollinators, and recommends that a honey bee swarm be collected by a beekeeper rather than sprayed. If you are unsure what you have, send a photo by text before anyone treats anything.

What treatment involves

Location first: a nest is treated where it lives, not where the insects are seen. UMaine Extension advises treating at night, when the wasps are least active, with product going straight into the nest entrance whether it is above or below ground. Enclosed nests in wall voids are the exception that catches people out — Extension’s guidance is to treat the entrance but not plug it, so the product is carried into the nest and the wasps do not chew through into the house.

Afterwards the nest material comes down where it can be reached, and the entry point is closed once the colony is dead so the cavity is not adopted next spring. For carpenter bees the gallery is treated and then sealed, and the bare wood needs paint or stain to stop the next female choosing it. The wasp, hornet and carpenter bee service page covers how a visit runs and what customers have said about it.

Updated 2026-10-04.