Flea larvae and adults can temporarily live in plants. Although female fleas lay eggs on the bodies of their hosts, the eggs fall off and lay in wait wherever the host goes, including lawns, gardens and yards. This is why it is important to include treating the lawn and yard if there is a flea problem in the home or on pets. Fleas usually do not live on house plants so these do not need treatment.
Lawns and yards need to be treated with insecticide sprays or granules to control fleas at the same time pets and inside of homes are being treated. Otherwise, the fleas will just go from a treated pet or home out into the yard and wait for a person or animal to walk by. The home or pets can be re-infested in this way. Insecticides often do not kill flea eggs and so another application in the home and in the yard needs to be done about 30 days later.
Flea adults and larvae live on the dirt or at the base of plants. Grass and other plants can act as a roof for fleas, getting in between insecticide and the fleas. Water the lawn or yard before applying any insecticide. The water weighs the grass and plants down so they are lying on the ground with the fleas. In order to keep away from the water, the fleas will climb on top of the plants. This is the ideal time to spray insecticide.
Insecticides that can be used on lawns or yards include permethrin or chlorpyrifos, best known as the brand name Dursban, according to the University of Kentucky Entomology Department. Insect growth regulators or IGRs can be added to liquid insecticides or they may already be mixed into the insecticide depending on the manufacturer. IGRs do not kill fleas but stop larvae from maturing into breeding adults. They types of IGRs that work best on fleas are methoprene and pyriproxyfen.
An entire back yard or lawn need not be treated. Concentrate on treating areas where pets or wild animals are known to congregate or sleep. Also treat along fences, in dog kennels or under decks. It is normal to still find fleas in the home and yard for about two weeks after the initial treatment because many insecticides do not kill flea pupae or eggs.