Beautiful Biocontrol: The Scoliid Wasp
If, in late summer, you notice a cloud of wasps careening in arcs and figure eights across the surface of the grass, don’t be alarmed and don’t reach for the pesticides. Celebrate these native beneficials that consume grub larvae and pollinate flowers! They are scoliid wasps– likely Scolia dubia or a close relative.
Although scoliid wasps may look intimidating when they congregate, they will only sting humans if severely harassed. Green June beetle and Japanese beetle grubs, on the other hand, have plenty to fear. A scoliid wasp stings a grub to paralyze it, lays an egg on its surface, and provisions an underground cell with additional paralyzed grubs for its larva to eat as it matures. She then repeats this process, dooming additional grubs as live feed for her offspring in other chambers.
Your best chance to examine these attractive wasps is while they feed on nectar. They enjoy a wide variety of flowers, including white clover and mountain mint. They have lovely metallic blue wings and a pattern of yellow spots on the abdomen that varies with the species and gender. Their distinctively curved back is the origin of their scientific name– think “scoliosis.”
Scoliid wasps’ many common names, including flower wasps, scarab hunters, and scarab hawks, remind us of their multiple functions in our ecosystem and their extraordinary value for gardeners.
Drew Pegon
Posted at 10:32h, 10 OctoberThanks Nicole. I rarely see these beautiful wasps except when they’re feeding on flower nectar, especially Mountain Mint’s. There are often so many on the plants’ flowers I’ve often thought we should list their flower color as black and red!
I’ve been threatening to do a proper I.D. for far too long, am grateful for your informative posting, and appreciate them all the more now that I know the wasps’ taste for grubs.
Thomas
Posted at 22:46h, 26 DecemberThanks for sharing, Nicole. Scoliid wasps are parasitic upon larvae of soil-inhabiting scarab beetles. Check out the Campsomeris plumipes species page: http://www.marylandbiodiversity.com/viewSpecies.php?species=6436
Marsha Reid
Posted at 21:13h, 17 JuneHow do I get them out of this camper we have inherited, they have become aggressive when I was trying to clean, I haven’t found their nest?
Lars Rasmussen
Posted at 13:52h, 19 JuneHi Marsha, if you have wasps in your camper, it is probably not Scoliid ones. Scoliids are ground nesting.. You are probably dealing with a nest of Paper Wasps. You may want to look/go after them on a cool early morning when they are less active with a can of wasp/hornet spray and a flashlight. -Lars
Charles Ivey
Posted at 07:28h, 21 JuneI was stung by a blk with yellow on the legs I’m thinking it’s paper wasp they were under my dock,how long will my hand and wrist stay swollen an burn.
John Hille
Posted at 09:57h, 19 AugustHundreds were swarming over my lawn this morning but not seen in my neighbor’s lawns. I recently sprayed my lawn for June beetles that were swarming in our bushes. I have also had issues in controlling moles in the yard and assumed that grubs were plentiful and the spray would help get rid of the mole’s food source. Just recognized the Scoviid Wasps today. Could they be so plentiful due to my recent attempt at controlling grubs as food source for the moles possibly are forcing them out of the ground?
Lennox Castleberry
Posted at 15:36h, 20 AugustHow are they around dogs?
Lars Rasmussen
Posted at 09:01h, 27 AugustI had a report of wasps flying around my Aunt’s yard and I volunteered to check it out before she sprayed them. They were the Scoviid Wasps, so I told them the benefits and she agreed not to spray. She was afraid of being stung but you can walk through an area slowly and not have that happen. I later saw a large population flying in low arcs over a cemetary lawn. John. I doubt the wasps were flying in mass in your yard because you had sprayed earlier. Very possibly they know where the large June and other beetle grub populations are. Lennox, I don’t think your dog will have any issues. They tend to leave our dog alone. It mind depend on how much a dog digs in the lawn! These are such a beneficial wasp and I have planted Mountain Mint on the property to attract them. -Lars Rasmussen Assistant Supervisor for Plant Health
Robbie B. Cuellar
Posted at 15:52h, 05 JulyReally, it is a Beautiful Biocontrol….
I want to thank you for sharing this!!!
Thomas Miller
Posted at 15:23h, 17 AugustBeautiful wasps. They are no problem to work around. I was amazed!
Carol Imamura
Posted at 10:00h, 24 AugustThank you for helping me identify these wasps. They recently appeared en mass on my deck where I have large pots of spearmint and peppermint that are flowering. I’m glad to know they are beneficial especially since I had a bad outbreak of Japanese beetles this year I’m sure they’ll take care of them!