Cicada Killer Wasps
These large wasps have a rusty red head and thorax, russet colored wings, and a black and yellow striped abdomen. A length of 1 1/2 inches is not uncommon. Larvae are white, legless grubs and are found in burrows in the soil.
The cicada killer wasp overwinters as a larva within a cocoon in a burrow in the soil. Pupation occurs in spring. Adults begin emerging in June and emergence continues throughout the summer. The adult female feeds, mates, and digs burrows for several weeks before preying on cicadas. A vertical or slightly angled burrow is excavated 6 to 10 inches deep and about 1/2 inch in diameter with broadly oval cells perpendicular to the main tunnel. The excess soil thrown out of the burrow forms a regular, U-shaped mound at the entrance.
Once cells have been constructed, the search for cicadas begins. Canvassing tree trunks and lower limbs, the female wasp stings her prey, turns the victim on its back, straddles it, and drags it or glides with it to the burrow. Each cell is furnished with at least one cicada (sometimes two or three) and a single egg before being sealed off. The egg hatches two or three days later and the larva feeds four to ten days, until only the cicada’s outer shell remains. During fall, the larva spins a silken case and prepares to overwinter. Only one generation occurs each year.
Cicada killers do not feed on plants. Larvae feed primarily on paralyzed cicadas, while adult wasps feed on flower nectar.
In spite of its formidable size and burrowing habit, this wasp is unusually docile and harmless. Although capable of inflicting a painful sting, the female cicada killer wasp is usually difficult to provoke. Mating males are aggressive and more easily disturbed, but cannot sting.
An unsightly mound of soil surrounds the burrow of each cicada killer. Since colonies of burrows are common, infested lawns usually contain several mounds that can smother the grass. However, since cicada killers prefer to nest in areas of sparse vegetation, it is likely that infested turf was already unthrifty when the wasps arrived. They rarely burrow in thick, vigorous turf. Burrows are most commonly found in ornamental beds or under trees or tall foliage plants where there are areas of bare soil. Wasps also preferentially construct burrows in sandy soils such as around playground equipment or in golf course bunkers.
Inspection & Control
Cultural controls can prevent or eliminate the establishment of cicada killer colonies. Adequate lime and fertilizer applications accompanied by frequent watering can usually eliminate an infestation in one or two seasons. In case of a severe infestation, chemical control may be necessary to prevent danger from stinging wasps.