Do you think wasps are eating your outdoor wooden furniture or structure? Technically they are not eating wood, but are using it as building material. Some wasps like paper wasps and yellowjackets will scrape wood with their mouthparts to make their paper nests. Some wasps nests in the holes of wood made from nails, drills, or emergence holes made by boring beetles. The powderpost beetle larvae food and live in wood until they pupate into adults and emerge out of the wood source to mate. These holes can be nesting sites for solitary wasps like potter and mason wasps.

Potter and mason wasps build mud pots in cervices or cavities in objects where they lay their eggs where they supply them with caterpillars or other insect larvae. Potter wasps are some of the smallest wasps in our area. The female is larger at 3/8” where the male is smaller, about 1/4”. Potter wasps like to nest in beetle holes about 1/8’ in diameter. Females will make a series of chambers with a wall of mud between each chamber. She will lay eggs in a chamber and hunt for tiny leaf beetle larvae and caterpillars. The female will sting her captured prey to immobilize it, but not kill it. She will put her captured prey in with one of her eggs and then seal each chamber. She will repeat this process until she had laid all of her eggs in that gallery. The female will cap off the entrance hole with more mud to give the offspring more protection and privacy to develop. Unfortunately for the potter wasps, there are tinier wasps that will parasitize her eggs if they find the chambers so the female will add mud over dummy holes to throw the parasitic wasps off their trail.
Most of the time potter and mason wasps are beneficial and do not eat wood. These wasps prey on other insects that eat plants, including garden pests. If the wasps are in wooden outdoor furniture, try to clean the item, remove any nesting sites, and seal any holes with wood putty or polyurethane. Then sit back and watch these wasps do their work.
For more information on wasps, please visit the Home and Garden Information Center website at hgic.clemson.edu. Tune in on Tuesday nights to watch “Making it Grow” at 7 p.m. on SCETV or mig.org. E-mail Outen at callenb@clemson.edu.
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