How Often To Apply?

Thursday May 31, 2007


Mr Pest Control


I would like to know how long you would say that a perimeter treatment with Talstar or Dragnet would last around a home, and the same thing for the non-repellent Premise 2. I know that it would depend a lot on the weather and that sunlight breaks down the treatment as well. But, in general, with fair to nice weather, how long would these general pest treatments be good for. I ask this because some folks want bi-monthly and quarterly treatments. I feel that 30 days would be the maximum residual and therefore I only offer monthly treatments. What are your thoughts, or do you know of any proven research concerning this? Thank you very much for any advice and help.

Richard W., TN

Mr Pest Control


My answer is going to be filled with personal opinions, and hopefully some insightful thoughts. First though, at a recent NPMA convention one speaker (a very well known university researcher) compared the effectiveness of various insecticides, and made the comment that 3 weeks was probably about as long as you could expect any of the pyrethroids to last around the exterior. While they are not nearly as susceptible to breakdown and degradation from UV light, water, heat, or soil alkalinity as their predescessors the organophosphates, their molecules still degrade fairly rapidly when exposed to the environment. Honestly, this is a GOOD thing. Those of us who remember chlordane will recall that one of the reasons it made anti-pesticide people nervous was because it was so stable in the environment. They don't like "toxic" things hanging around for very long.

How long a chemical molecule will last varies widely. The Dragnet (permethrin) placed in the soil under a concrete slab may continue to have an effective residual for many years. That same chemical applied to a sidewalk in the sun could degrade within days or a week or two. This becomes our double-edged sword. On the one hand, if we have products that last for months we can minimize our applications and still provide what many customers bugs even around the exterior of the home. On the other hand, if we use products that lose their effectiveness within just a couple of weeks we may need to resort to more frequent applications. I think part of the solution is in managing the EXPECTATIONS of the customers. The general public may be siding with the anti-pesticide people and demanding the increased restrictions on pesticide use, but by golly they still want you to keep all bugs from even passing the fenceline and entering their property. This has to change.

Most PMP's now provide the assurance to their customer that they will keep pests out of the home, not out of the yard. Ants on the back fence belong there and are a natural part of the environment. Ants in the home become an unacceptable nuisance. We should not pursue a scorched Earth approach to pest management, by overloading the exterior environment with pesticide in the effort to kill every bug that wanders onto it. There of course are exceptions to this rule. A colony of fire ants near the back fence still is too darned close, and black widow spiders in the shrubbery is too many black widow spiders. We must find that balance in our work where we preserve the beneficial insects and other predators in the outside environment while still meeting the needs of the customer. Selectively applying our products to the niche environment of the pest is better than power spraying the entire yard.

Pyrethroids applied against the foundation are going to be less affected by outside conditions than are products applied to lawns, fences, sidewalks, and other exposed surfaces. If you were to treat under the eaves for spiders you have removed exposure to UV light and the intense heat of the sun, so you might add a week or two to the effectiveness. If you treat within walls for ants you could get a month or two from a product. Premise (imidacloprid) probably will be in the same range as the pyrethroids. The active ingredients do not suddenly blink out of existence, but degrade slowly, more or less a molecule at a time, until you have too little of the active ingredient available for the passing pest to acquire a dose that will affect it.

On the subject of monthly vs bi-monthly or quarterly services, here is my unsubtantiated opinion, and again it goes back to Managing Customer Expectations. If you have a customer who, for whatever reason, is completely, absolutely, utterly intolerant of ANY bugs then you may need to give that monthly service. In essence, to satisfy this demand you may need to go to a higher level of pesticide application in order to maintain an effective residual around that home at all times. However, if you can explain to the receptive customer that your goal is to keep their home pest-free, but not to annihilate all living creatures on the property, then they may well understand that seeing ants and earwigs around the yard is appropriate (maybe even a good sign of a healthier yard). You will eliminate those present adjacent to the structure, and with another application 2 or 3 months later knock down any populations that have started to rebuild in those areas. You also can use very selective products, such as insect baits, to control specific pests without affecting any other animals that live in the area.

The customer can have a huge role in this process, and your inspection of their property should point out all the contributing conditions that are allowing pests to live there in the first place. Any piles of rubbish or yard debris sitting on the soil encourage pests by providing harborage. Excessively wet areas may breed mosquitoes, flies, encourage springtails or pillbugs. Obvious openings in the exterior of the home allow pests easy access to the inside. Shrubbery growing over the soil or thick groundcovers and mulch provide cool, damp harborage for many pests. If the customer truly wants a pest free yard and one that is not continually sprayed with insecticide, they will cooperate and do the important IPM steps in fixing the environment of the pest. If the customer is strange, and wants that constant layer of pesticide on everything then......well,......that has to be dealt with too.

Bottom line is I would definitely offer more than just monthly services, but TALK with the customer so they understand the reality of what is likely to happen as the insecticide around the home dissipates. You probably should charge more for the quarterly service with the expectation that you will spend a bit more time every 3 months than you would every month. If anything, the attacks on our industry from anti-pesticide groups are increasing, and they now have some very sympathetic ears running our federal government. We cannot give them anymore reason than we need to to go after what we do.

Mr. Pest Control

Register now for PestWeb to get instant access to all of Mr. Pest Control's in-depth answers!

Register Now Ask a Question Add to My Favorite Questions

Please note, Mr. Pest Control is answering questions supplied by PMP customers across North America. His answers are generated from industry and manufacturer-provided information. The answer may not be specific to the laws and regulations for your State, Province, Territory or Country. In addition, products mentioned may not be registered and or available in all areas. Always check with your local Univar office for specific information to your area. Always read and follow label directions.