Bayer’s Jeff Einam shares his tips on how to treat fleas to ensure they’re gone for good.

Flea treatments are one of the most specialised pest management activities you will undertake because it involves the application of a fine mist of insecticide across all horizontal surfaces where fleas are present. Internally this will include many highly sensitive surfaces that must be treated and yet there is a high chance of unacceptable damage if it is not done correctly. The flea and its larvae do not discriminate as to which surface they will inhabit, so you must ensure complete coverage in order to bring about the destruction of the entire life-cycle.

The adult female flea finds a good feeding site on the host animal and feeds exclusively on the blood. She lays eggs and excretes small droplets of blood as food for her larvae from this secure feeding position so anywhere the animal moves, flea eggs and food continuously drop into the environment.

The eggs soon hatch into larvae, which are tiny caterpillar-like animals able to move freely across just about any surface in search of food. The larvae moult three times as they grow and feed on the organic matter they readily find in the pets environment.

After they have grown through to the third instar, the larvae will knit itself a cocoon in which it will completely transform into the adult flea. This cocoon is completely impregnable to insecticides and will protect the insect from any harm. The fully developed adult flea will remain in this protected cocoon right up until the point it emerges.

The flea can remain in this dormant stage for a very considerable time period, even as long as 12 months. The major stimuli for the adult to hatch are vibration and body temperature, both signals indicate a host is in range and the chances of getting an immediate blood meal on hatching are high.

Understanding this complete lifecycle is the key to effective control of this insect. In any one infestation over 85% of the fleas will exist in either the egg or larval form, so this stage is a very important target for your treatment.

An insect growth regulator (IGR), such as Bayer Starycide is ideal for the control of immature stages of fleas due to its long persistence and very low toxicity to mammals. The active ingredient is a chitin synthesis inhibitor (CSI), which kills juvenile insect forms as they moult – so with fleas you get three chances to control the insect as they grow, from each instar to the next.

Starycide from Bayer

Controlling fleas at this stage will mean that 85% of the infestation will never reach maturity and become a pest. This product, however, will have no effect on an adult insect as it no longer moults once fully grown.

So how do we kill the other 15% of the population? Let’s start with the adults, which normally are only about 5% of a given infestation. Synthetic pyrethroids, like Bayer Cislin 25, are excellent adulticide products and kill adult fleas very quickly.

Cislin 25 from Bayer

It is recommended to add a small drop of wetting agent to your spray to assist with adherence to the highly waxy body of an adult flea. Application is best when applied as a fine mist (i.e. very light spray) as it needs to contact all horizontal surfaces where the pet has visited.

Before carrying out a treatment, prepare the area appropriately:

  • Always do a walk-through of the area and cover sensitive surfaces (e.g. televisions, highly polished furniture, computers, food preparation surfaces, etc.)
  • Any exposed foodstuffs need to be put away
  • Remove pet food or cover feeding bowls
  • Cover fish tanks and pump. Turn off the air pump (remember to turn it back on after the treatment has settled)
  • In external areas insist the grass is cut short, sand areas need raking and dry areas should be pre-wet with water prior to the application
  • Animals need to be removed from treatment areas and should not return until the spray has dried!

So what about the 10% in the pupal stage? There is no product available to you that will penetrate the protective cocoon and kill this stage. You must therefore manage this shortfall by other means involving physical modification of the environment. As we mentioned before, the pupae are stimulated to hatch by vibration and body temperature, so we need to use these stimuli to hatch out the fleas during the period when our chemicals are most active. In many situations the presence of the homeowner and host animal is all that is needed to provide the stimuli.

However what happens if the animal is no longer there, as can often be the case in rentals or holiday homes? It is essential that if the animal is no longer present then someone else must provide the stimuli. A person needs to move slowly and methodically through the area stomping as often as possible to get the pupae to hatch. It’s often hard to find a volunteer for this but someone needs to do it. Your compressor running on the floor of the treatment area will certainly help. Once the flea emerges and contacts the active ingredient it will quickly die and the infestation is stopped in its tracks. The only thing left now is to treat the host animal.

Treatment of the dog or cat is not a pest management activity and none of our pest control products are registered for direct application to animals. There are, however, excellent pet products available for flea control on dogs and cats, which are administered by the owner. Advocate and Advantage are two such products produced by Bayer. The product is applied directly to the back of the neck and along the spine of your cat or dog. This application is repeated on a monthly basis and will keep your animal flea free, so long as you keep to the application schedule.

Jeff Einem, Technical and Regulatory Affairs Manager, Bayer Environmental Science