Home Maintenance Guide

St. Louis Observer

Covering Greater St. Louis & Rural Missouri
Stinging Insect Guides  |  Wasp ID Guide  |  Summer Pest Guide
Missouri  •  Pest Control Guide

Missouri Wasp Nest Guide: Identifying What You Have and When It's Safe to Act

Not all wasp nests are the same situation. A paper wasp nest on an eave in March — small, queen alone, just getting started — is a different risk than a yellow jacket colony in August at 5,000 workers with a nest in the wall void of your house. Understanding what species you're dealing with, where the nest is, and what time of year it is determines the right response.

Three Nest Types Missouri Homeowners Encounter

Paper Wasp Nests

The open-comb umbrella-shaped nests attached to eaves, porch ceilings, and doorframes are paper wasp nests — the most commonly encountered nest type in Missouri. Paper wasp colonies are relatively small (20–75 workers at peak) and the wasps are not particularly aggressive unless the nest is directly disturbed. Nests attached to structures away from high-traffic areas can often be left until after the first hard frost, at which point the colony naturally dies and the nest can be knocked down and discarded. Nests over doorways, children's play areas, or other high-contact locations warrant treatment.

Yellow Jacket Nests

Yellow jackets are the high-risk wasp in Missouri — large colonies (up to 5,000 workers by late summer), aggressive defense of the nest, and a tendency to nest in concealed locations including wall voids, crawlspaces, attic spaces, and underground. Yellow jacket colonies peak in late July through September, which is when the most serious stinging incidents occur. A nest in a wall void requires professional treatment — attempting to seal the entry without treating the colony drives wasps further into the wall and creates interior access points. Yellow jackets in the ground or lawn are treated with dust insecticide injected into the entrance at night.

Bald-Faced Hornet Nests

The large gray paper-mache football-shaped nests in trees and shrubs are bald-faced hornet nests — technically a yellow jacket species. Colonies reach 400–700 workers by late summer. The nest is usually conspicuous by mid-summer once it has grown to visible size. Bald-faced hornets are aggressive within 3 feet of the nest; treatment requires a pyrethroid aerosol directed into the nest entrance at night. Professional treatment is the appropriate approach for nests near structures or high-traffic areas. Like all wasp species, the colony dies after the first hard frost and the nest is not reused the following year. D&D Pest Control treats stinging insect nests throughout Franklin County and rural Missouri — visit ddpestcontrolmo.com.

Seasonal Timing

Spring (Apr–May)

Queens founding new nests — small, low risk. Paper wasp nests just 4–6 cells. Yellow jacket queens underground. Easiest intervention window.

Summer (Jun–Aug)

Rapid colony growth. Yellow jacket colonies hit thousands. Bald-faced hornet nests become visible. Aggression increases as colonies mature.

Fall (Sep–Nov)

Peak colony size and aggression in September. Colonies decline in October. After first hard frost, all workers die and nests are abandoned permanently.