Environmental Flea Control

The Flea Colony

Many of our clients who are trying to control fleas on their pets do not understand that the fleas actually live in a “flea colony”, which takes one to two years to create in the typical pet owning household. This flea colony occurs after many generations of fleas are allowed to develop because of a constant source of food (blood) from the pet. The fleas that we see on our clients’ pets come from the immediate environment that the pets live in. These fleas are usually newly hatched, hungry fleas that are in search of their first blood meal. Following this meal they will breed and after subsequent blood meals, the female will lay eggs. If these fleas are killed while on the pet by a spray, dip or powder, other fleas from the same colony will replace them. Many colonies can produce thousands of fleas each day. The flea colony will only develop where there is a dependable source of food. A colony of fleas will develop in shaded, moist locations, around the food bowl, under the favorite bush, or on the rug where the pet frequents.

Figure 8. Fleas shown on top of grass blades to gain view of pet. An expedition is then undertaken to make their way to this new host. NOT!!!

Fleas from this colony will infest the pet for feeding purposes – to supply the necessary fuel to produce the large quantity of eggs that a female flea can generate (over twice her body weight per day). The eggs, which are laid on the pet, will roll off the pet into the colony and hatch to replenish the colony.
These newly hatched fleas will be in a location where they can acquire a rapid meal and complete the cycle again.

Many clients will use the excuse of “I cannot control our fleas if our neighbor will not control theirs”. This is not valid because the neighbor’s fleas are located in their “flea colony” in their yard, and fleas for this client’s pets are located in the habitats conducive for “flea colony” development in their yard. Furthermore, fleas are not travelers – they do not, for example, jump onto a tall blade of grass to “see” a pet in the next yard, then start an expedition to that yard to infest that pet. Fleas jump very well, but only in the “up” direction to “catch” a passing pet.

Fleas seem to have an innate knowledge of where their colony of origination is and will exit the pet when he arrives back in this location. Studies done on squirrel fleas have shown that a flea colony will exist in the squirrels den or nest and the squirrel will be infested with both male and female fleas. These fleas however will not jump off this squirrel while the squirrel is in transit across the treetops or on the forest floor. These fleas will wait until the squirrel reaches his den to lay eggs and to leave the body of the squirrel. The fleas will breed, lay eggs and reside within this “colony” until they need another blood meal. Certainly it would be difficult for a flea to jump off a squirrel in the forest and expect to see other fleas or to have another squirrel come by for a meal. This type of activity of flea mobility occurs with our domestic pets as well, and we can draw some conclusions from these studies.

  • Fleas are not transmitted to a pet in the back yard by passing wildlife or other domestic animals unless they frequent an area enough for a “flea colony” to develop there.
  • Flea colonies take some time to develop – at least one year and perhaps two to three years.
  • A household could not be infested with fleas by a pet leaving the Animal Hospital with fleas. The fleas on the pet would be adult fleas and would be easily killed by one application of pesticide. If there were more fleas seen after this application then there must already be a flea colony established.
  • Fleas use other methods to insure that a blood meal is present before they actually emerge from their cocoon.
  • The flea pupa hatches within one second! Upon sensing appropriate vibration, heat and carbon dioxide levels, fleas can hatch and jump onto a pet as it walks by. Carbon dioxide is exhaled close to the floor by a panting dog or child and the vibrations and heat are obviously caused by pets or humans moving.

A “flea colony”, may for example, be residing in a summer home. The clients leave the home unattended for some time returning again the next summer. Prior to their departure they might spray or bomb, which kills all the adult fleas and does not kill the pupas. Meanwhile, the eggs will hatch, and the larva stages will develop into pupa. Upon returning, the people and pets are attacked by tremendous numbers of fleas. This scenario is similar to what might happen when one of our clients might go on vacation as well. Upon arriving home from a vacation, the pet might have been boarded at the veterinary hospital and perhaps bathed there as well. The client might think that the pet came home with fleas from the hospital. This misconception can be prevented with the preceding knowledge and by showing the client that the pet is flea-free prior to departing from the hospital.

Flea Yard Control

Recent advances in the development of flea control products have greatly changed the recommendations for environmental control of fleas. The control of the yard as the ultimate source of fleas was a large part of the effort for many years. With today’s newer products, flea control can be successful without pesticide application to the yard. Nevertheless, in certain areas of the country where the environment is perfect for flea reproduction, every weapon is necessary for the flea battle. Your primary function is to educate our clients on effective use of products in the effort to control fleas. To assist our customers, it is important that we comprehend appropriate application justifications and methodologies. All forms of flea control should be used if the pet is in danger of serious disease such as flea anemia from the excessive flea burden.

The adult flea in the environment, or on the pet, is very easy to kill and almost any insecticide will work. However, the cocoon stages are very difficult to kill regardless of the insecticide used. Typically, new fleas will be hatching and noticed on the pet within four days after flea adulticide treatment. This fact will lead many clients into thinking the flea product was not powerful enough or did not work at all. These newly hatched fleas need to be killed before they lay new eggs (within ten days). The eggs may hatch anywhere from twelve days to six weeks depending on the environmental conditions. This allows for almost constant re-infestation of the environment. We must kill the fleas at the adult, egg and larval stages using the correct frequency of re-application to be effective. Killing fleas after hatching, but before laying new eggs, is an effective way to break the life cycle.

Organophosphate insecticide granules are recommended as a powerful and residual adult and larval flea killer. Either Dursban® (chlorpyrifos) or diazinon granules are effective for the yard. These products consist of a bait substance (corncob) to which the pesticide has been bonded that the developing flea larva will eat and die. The adult fleas will die when they come in close contact with the granules in the yard. The granules have a residual action resisting degradation by rain and dryness. The yard should be prepared by mowing the grass, picking up the debris, raking, and pre-wetting the yard. The granules should be applied from curb to curb and fence to fence especially on any moist or shaded area such as under shrubs and around the doghouse. The granules should then be blasted with water through the grass down to where the flea lives in the soil. The first application of flea granules should be used with a liquid form of insecticide spray that gives quick “knockdown”. This first application of the granules should be soaked with an application of a liquid insecticide such as diazinon or Dursban® which can be done with the water blast (hose-end sprayer) or after the water blast. This will give the combination of quick kill by the liquid and the residual action of the granules. During the flea season, apply granules every week for four treatments then monthly to maintain coverage. With this program, the flea population should be controlled and the colony eliminated. If Dursban® is used, fire ants and chinch bugs should also be killed.