Egg -- The pearly white egg is ridged lengthwise and measures about 0.5 mm in length.
Larva -- The mature larva is white or opalescent in color and about 3 mm in length. Its body is maggot-like, the head being pointed.
Pupa -- The pupa develops within the skin of the last larval instar. This 2.25 mm long skin, known as the puarium, is straw-colored at first but gradually turns chestnut brown.
Feeding Habits -- Eye gnats are readily attracted to man and most animals. Eye gnats feed on mucous or sebaceous secretions, pus, and blood. These insects do not pierce the skin of the host.
Damage -- Eye gnats are very annoying and persistent pests. If brushed off, they quickly return. Though they are primarily an annoyance, eye gnats do spread disease organisms that cause conjunctivitis (pink eye), anaplasmosis and bovine mastitis. In North Carolina, the major economic damage they cause is to the recreation and tourist industry. Eye gnats can be extremely annoying on golf courses, particularly in the Sandhills area.
Life History -- Eye gnats may be present all year if the weather is mild; however, adults are most numerous from June to November. After mating among shrubs and brush, females deposit an average of 26 eggs over an 18-day period. Eggs laid on or below the surface of soil which is moist and which had fresh vegetation turned in hatch in about 3 days.
The small larvae burrow into the soil where they feed on decomposing organic matter. The larval stage lasts about 11 to 17 days under normal conditions but may require several months during cool weather. Mature larvae pupate near the surface of the soil. Adult eye gnats emerge 6 to 10 days later. Females begin depositing eggs within 5 to 8 days. A complete life cycle (from egg to egg) requires about 28 days under optimal conditions. Adult eye gnats are persistent fliers and have been carried by the wind more than a mile from their breeding site.