Mar 11, 2012 – Label Confusion

QUESTION:

I recently purchased a quart of Demand CS to do basic household pest control at a few of my accounts. The label does not come right out to say how much I should use for a given situation. It has a rate table with three different application rates. Could you please explain what these three rates mean and when I should use them? Also I heard from a friend in the pest industry that as a "rule of thumb" you use 2 ounces per gallon for initial perimeter sprays and 1 ounce per gallon for maintenance perimeter sprays. Please let me know if this would be a good rule to follow as it seems more than the recommended label application. Thank you so much!!

ANSWER:

Well, I will agree with you that pesticide labels can, at times, be a little confusing. And, just to keep in mind, all of the product labels of synthetic pyrethroids (like the lambda-cyhalothrin in Demand) will be adding new wording and restrictions on their uses this year, as manufacturers package new batches and ship them to suppliers like Univar. You can use the product according to the label on the container that you purchase, but please read the Label carefully each time you buy more material so you know when the new wording shows up and must be followed. 

I have long preached that it is important to read the full label of every product you use, and that means every single word on the label. You may not do this every time you use it, but now and then refresh your understanding of just what THAT label requires. Each product label may be slightly different and require slightly different procedures, and you must follow what that label tells you to do. These differences may be with respect to how the product can be used, how it must be mixed, what PPE you must wear, laundering instructions, etc. For example, on the Demand label it allows you to mix Demand with other insecticides, but you MUST add the Demand last, and if a regulatory inspector were watching you and reading the Label himself he would cite you if you did not follow this procedure. 

Many or most insecticide labels offer several use rates, such as the three choices on Demand CS of 0.015%, 0.03%, and 0.06%. If you scroll down the page a little you find some *** that explain these things, and here one asterisk tells us that the lowest concentration would be for "maintenance" uses for roaches, the 0.03% for "cleanout" uses, and the highest rate for "severe" infestations. What it is allowing you to do is to place higher levels of the active ingredient when roach populations are very high, leading perhaps to faster kill of those many roaches. This sort of leaves it up to you to decide which scenario you are facing. There are little numbers following some of the pests in the list, and these numbers are further explained below the rate table. For example, the number "4" following "Mosquitoes" tells you to use the high rate (0.06%) for outdoor use if you hope to leave a residual for barrier treatments for adult mosquitoes. 

So, the Demand CS label seems to do a pretty good job of explaining when and why to use any of those listed rates. However, I believe that your friend's suggestion of a cookie cutter approach to mixing is dangerous, and please do not do what he suggests. Even on the Demand CS label that "2 ounces per gallon" would be nearly 3 TIMES HIGHER than the label allows even at the highest rate of 0.06%. If he is doing that he is badly in violation of the label and would be cited if caught. For maintenance perimeter sprays the Demand CS label offers dilution rates for exterior use, and again they provide various scenarios that you can choose from - if you are using a 1 gallon sprayer it is assumed you might use that 1 gallon over about 1000 square feet of surface, and again the HIGHEST rate allowed is only 0.8 ounces of Demand CS in 1 gallon of water, or nearly 3X less than your friend suggests. 

I won't look at any other product labels because I think this already serves as a good example of why you need to read each label and recognize that every product may need to be mixed in a different manner. Another thing that is important for you to do is to "Calibrate" your application, and this means that you need to know approximately how much surface YOU spray with one gallon of liquid when you apply it in your normal manner. Some technicians might move more slowly and that gallon could only cover 500 square feet of surface, whereas others might move more quickly and cover 2000 square feet. There is nothing wrong with this, except the desire is to place the proper amount of the active ingredient over each square foot, and this will determine how much concentrate to add to your gallon of water. 

Take a clean 1 gallon sprayer with the tips and nozzles in good, clean condition and add exactly 1 gallon of water only. Then, mark off an area of maybe 250 square feet on a hard surface like a patio or driveway - 250 square feet would be 10 x 25 feet. At the speed you normally walk and spray you then evenly spray that 250 square feet and then empty your sprayer into a container to measure how much water remains. You then know exactly how much liquid you used to cover 250 square feet of surface. This might be a huge surprise for you. Since a "normal" rate of 1 gallon per 1000 square feet means you would use 1 quart of spray solution over 250 square feet, if you managed to empty your whole gallon on that 250 square feet, or perhaps used only a pint, you now can determine how much YOU would use over 1000 square feet. This is going to keep your applications within the allowable rates on the product label. 


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