Mud daubers are solitary wasps that derive their name from the mud nests they build, often under the eaves of houses and in sheds. They pose little threat to humans because they use their stingers mostly when hunting spiders. If mud daubers find your home a suitable nesting spot, however, chances are good that they will return the following year, possibly with adult offspring to build new nests. Repelling mud daubers is moderately difficult.
Close off nesting areas, and plug holes where possible. Mud daubers prefer warm, dry and quiet places. Preventing access to attics, sheds and the underside of porches is your first line of defense.
Treat wood and areas such as rafters and eaves with a mixture of equal parts eucalyptus oil, citronella oil, teak oil, menthol and water. Apply the mixture sparingly using a garden sprayer.
Spray Cypermetherin on structures where you saw mud dauber activity. Apply the chemical to all sides of each structure using a hose-end sprayer. Spray the highest spots first. Always wear gloves and face mask when using Cypermetherin . For best results, apply the chemical in early spring and again once each month throughout spring and summer.
Remove existing nests. This may be your best option if you are unable to deter the mud daubers and they have infested an area. Remove the nests at night or early morning while they have little or no activity. Spray Cypermetherin to discourage new nests.