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Identification and Biology
Adult fleas are small (1/8 inch) and laterally compressed, which allows it to easily maneuver through the hairs of its host. The strong hind legs are specially adapted for jumping. Adult fleas are black to reddish- brown, but young adults that haven’t had their first blood meal are quite small and black in color; after feeding they expand and appear lighter brown. The hairy, worm-like, white larvae, which are 1/16 to 3/16 inches long, have a distinct brown head.
Unlike many other flea species, adult cat fleas remain on their host. After mating and feeding, adult female fleas lay white eggs. These smooth eggs easily fall from the host into cracks, crevices, carpet, bedding, or lawn covering. A mature female flea can lay up to 25 eggs daily for three weeks.
Small, worm-like larvae (1⁄16 to 3⁄16 inches long) hatch from the eggs in 2 to 12 days. They have a distinct brown head and are eyeless, legless, and sparsely covered with hairs. The larval body is translucent white and a dark-colored gut can be seen through the flea’s skin. Flea larvae feed on dried blood excreted by adults. They will also eat dandruff, skin flakes, and grain particles. Larvae live in cracks and crevices or on the ground where eggs have fallen. Under favorable conditions, they take 8 to 21 days to develop, but they can take up to 200 days under unfavorable conditions.
Larval fleas metamorphose into adults within silken cocoons. The cocoons camouflage by attracting dirt and debris to their sticky exterior. New adults are ready to emerge from their pupal cocoons within two weeks under good conditions. They can, however, remain in their cocoons up to 12 months if no host is available or if climactic conditions are unfavorable. Vibrations and/or elevated temperature stimulate adults to emerge from their cocoon. Because of this ability to delay hatching, the presence of a host can result in a sudden increase of adult fleas when they emerge simultaneously from many cocoons.
As soon as the adult fleas emerge from the pupal case, they seek a host that will provide the first blood meal. Adults can live 1 to 2 months without a meal or 7 or 8 months with one. They are the only stage that lives on the host and feeds on fresh blood. The flea population builds up all year long in the form of eggs, larvae, and pupae, but rapid development into biting adults require correct temperature and humidity conditions and host signals for the adult to emerge from the cocoon.
Flea bites cause irritation to humans and animals, but also can cause serious allergies. Other more serious and less common problems are associated with the cat flea. Cat fleas (the most commonly found flea in schools and homes) can carry or transmit various organisms, such as Yersinia pestis, which causes bubonic plague; Rickettsia typhi, which causes murine typhus; and Dipylidium caninum, the double-pored dog tapeworm, which can live in dogs, cats, or humans. Tapeworms are transmitted to a vertebrate host when the vertebrate ingests an adult flea carrying a tapeworm cyst.
Detection and Monitoring
Fleas can be a problem in schools even if pets do not live in the buildings. Adult fleas can be brought in on the clothing of staff, students, or visitors. Other possible sources include urban wildlife such as rats, feral cats, raccoons, opossums, chipmunks, squirrels, or birds that may live undetected in unused parts of the buildings. Detection is as simple as finding fleas or noticing bites around the ankles of people in the building. Flea dirt, the adult flea fecal material that dries and falls off the host to serve as food for larvae, may be visible. Tapeworms, transmitted to a human via ingestion of an infected flea, would also signal a flea infestation.
Areas to Monitor
An integrated management program for fleas can be designed by selecting from the following strategies and tactics.
Insect-destroying nematodes (Steinernema carpocapsae) can be applied to the lawn as a spray. These microscopic, worm-like organisms live in the soil and kill insects by entering their bodies, feeding on their tissue, and releasing harmful bacteria. They do not affect people, pets, or plants. When the nematodes mature and reproduce, the nematode larvae leave to search for other hosts. They cannot move far (only 1 or 2 inches) and die if they fail to contact other insects. The nematodes sold for flea management are native to the United States and are found naturally in the soil nationwide. They will not adversely affect earthworms, but may attack insects other than fleas. Nematodes may not be effective in some situations, and may also require monthly applications.
If nonchemical methods alone are ineffective, or only partially effective, then integrating a pesticide into your management program may be warranted. Anyone making pesticide applications on school property must be licensed by the Board of Pesticides Control. See “Standards for Pesticide Applications and Public Notifications in Schools”.
Anyone making pesticide applications on school property must be
Information from this page can be found on the National School IPM "Fleas For Schools" web page. The page, with additional information, can be accessed at: http://schoolipm.ifas.ufl.edu/newtp5.htm
IPM For Fleas in Schools [PDF] (Pennsylvania)
Joseph Berger, Bugwood.org
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