Grass Carrying Wasp

black wasp with thin waist resting on composite flower buds
Photo by Judy Gallagher

Scientific Name

Genus Isodontia

 

Size

3/4″

 

Key Features

  • Black with pale hairs on the thorax
  • Brown to black wings held apart at rest

Biology and Habits

Grass-carrying wasps are solitary wasps and are rarely aggressive, but can sting if disturbed. Females construct nests within cavities above ground and provision each cell with a paralyzed tree cricket and an egg. Each cell is lined with grass blades. Occasionally, a female will build her nest within the tracks of storm doors or windows, with dried grass seen sticking out of the openings. Adults may be seen visiting flowers in search of nectar or prey. 

 

Control

Although grass carrying wasps are beneficial insects and do not often come in contact with people, occasionally they may nest inside the tracks of storm windows and doors, leaving behind dried grass. In most cases, the grass can be simply cleaned up without any need for control. If wasps are a recurring problem, calking openings will prevent further reinfestation. Dust may be used inside of the tracks or other cavities to kill larvae. A liquid treatment around windows and doors can also eliminate adult wasps. 

Need help identifying or controlling this pest? Give Revolution Pest Defense a call or send an email for a free inspection.

Nate Walton, M. S. U. E. (2023, October 30). The grass-carrying wasp: A solitary wasp that builds an unusual nest. Michigan State University. https://www.canr.msu.edu/news/the_grass_carrying_wasp_a_solitary_wasp_that_builds_nests_in_unusual_places

 
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