Biology and Habits

Great black wasps are solitary wasps and are rarely aggressive, but can sting if disturbed. Females dig branching tunnels up to a foot deep in sandy soils to construct cells. Each cell is provisioned with several paralyzed katydids and an egg. Great black wasps are a natural source of pest control for katydids and grasshoppers as well as pollinators of several plants including milkweed, carrot, and beans. 

Control

Great black wasps rarely become a nuisance and control is not recommended. In situations where populations become too large, individual nests can be treated to kill developing larvae and adults. However, as these wasps are beneficial insects, it is best to leave them alone.