Cicada Killer Wasp
Sphecius speciosus (Drury), Sphecidae, HYMENOPTERA


DESCRIPTION

Adult -- This large wasp has a rusty red head and thorax, russet colored wings, and a black and yellow striped abdomen. A length of 30 mm or more is not uncommon.

Egg -- The translucent, greenish-white egg is often described as "cigar-shaped." Its measurements range from 3 to 6 mm in length and from 1 to 1.5 mm in width.

Larva -- The larva may reach a maximum length of 28 to 32 mm. The mature, quiescent larva, however, is somewhat shrunken and leathery.

Pupa -- The pupa remains undescribed. The woven, spindle-shaped case which surrounds the pupa averages 32 mm long and 11 mm wide and has a narrow band of pores along its center. The case is often brown and stiffened.


BIOLOGY

Distribution -- The cicada killer wasp occurs in all states east of the Rocky Mountains. It abounds in areas of full sun, scant vegetation, and light textured, well drained soils.

Feeding Habits -- The cicada killer was is not phytophagous. The larva feeds primarily upon cicadas. The adult wasp feeds on the nectar of flowers.

Damage -- In spite of its formidable size and burrowing habit, this wasp is unusually docile and harmless. Although capable of inflicting a painful sting, the cicada killer wasp is usually difficult to provoke. Mating males, however, are aggressive and more easily disturbed.

An unsightly mound of soil surrounds the burrow of each cicada killer wasp. Since colonies of burrows are common, infested lawns usually contain several mounds that can smother the grass. However, since cicada killer wasps prefer to nest in areas of sparse vegetation, it is likely that an infested turf was already unthrifty when the wasps arrived. They rarely burrow in thick, vigorous turf.

Life History -- The cicada killer wasp overwinters as a larva within a cocoon 15 to 25 cm deep in well drained soil. Pupation occurs in the spring. The cicada killer wasp's life history has not been closely studied in North Carolina, but the wasp appears as early as the first week of June in Arkansas and rarely before July 1 in Ohio. Emergence continues throughout the summer. The female adult feeds, mates, and digs burrows for several weeks before preying on cicadas. A vertical or slightly angled burrow 15 to 25 cm deep and 1.2 cm in diameter with broadlfy oval cells perpendicular to the main tunnel is excavated. 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 wasp stings its 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. Two to 3 days later the egg hatches. Depending on the number of cicadas in its cell, the larva feeds for 4 to 10 days until only the cicada's outer shell remains. During the fall, the larva spins a silken case, shrinks, and prepares to overwinter. Only one generation occurs each year.


CONTROL

Cultural practices can prevent or eliminate the establishment of cicada killer wasp colonies. Adequate lime and fertilizer applications accompanied by frequent watering promote a thick growth of turf and can usually eliminate a cicada killer wasp infestation in one or two seasons. In case of severe infestation, chemical control may be necessary to prevent danger from stinging wasps. For recommendations, consult the state agricultural extension service.