Tuesday, September 22, 2015

Pest Spotlight: Wasp Safety for Autumn

Paper wasp females seek nesting locations indoors as autumn
cool weather approaches and prefer cathedral or very high ceilings.
By Aimee Marshall
NC Cooperative Extension

Wasps are social insects that are attracted to sweet drinks and meat and are at their peak in late summer, just as families are enjoying comfortable evening weather outdoors: grilling, camping, doing yardwork, and gardening in preparation for fall. Hornets and yellow jackets will lay about 1,500 eggs throughout the season, while paper wasp queens will lay several hundred.

Yellow jackets, paper wasps, and European hornets occasionally interfere with outdoor activities when they nest in lawns, trees, and under the eaves of houses. Wasp nests have also been encountered under grills, at the base of shrubs, and in other sheltered spaces (such as under equipment or garden supplies).

While paper wasps tend to be less aggressive than yellow jackets and hornets, any wasp is capable of targeting a passerby and stinging multiple times—causing localized allergic reactions for most but potentially life threatening reactions to sensitive individuals.

Colonies survive well into fall but die out by winter. If control measures are needed before winter for health and safety reasons, treatment should be done at night when all workers have returned to the nest and are calm and resting. Typically wasp and hornet sprays that shoot 10 to 12 feet into an aboveground or below-ground nest are most successful, killing the colony within 24 hours. Be sure to remove what remains of the nest, including the brood cells so that emerging pupae do not recolonize the nest.

Despite the potential hazards, wasps are actually beneficial insects. They prey on many types of pests, particularly caterpillars, so they can be tremendous assets to gardeners.


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