First, please don’t confuse mixture rates with application rates. In this blog I want to address a common discussion with our new clients… application rate. There are 2 broad categories involved: direct spray and residual sprays. For residual applications, the most common industry standard is always 1 gallon of spray per 1000 square feet of surface (we do the math to break this down to our typical 4”x4” panels). For most indoor and perimeter spray applications, 1 gal/1000 sq ft is the best ‘go to’ plan for testing. However, when planning for applications to plant material, the most common application is ‘until wet’ which is obviously a little vague, but due to the difference in the wax layers on each plant species, this is typically the best plan possible. Another common term for many labels is ‘spray until runnoff’ which is similar to the concept of ‘until wet’ for plants, but ‘until runnoff’ is more commonly referred to for broadcast applications over large surfaces for indoor/outdoor spray products.
Another concern regarding the application rates for residual tests is the target equipment that is to be used. Ideally we want to use equipment that would be typical of the applicator for the product. In many cases we will recommend the use of compressed air sprayers with either a flat fan or full cone spray nozzle and apply the product for the equivalent of 1 gal/1000 sq ft. However, when the product is to be packaged in a trigger sprayer, it is more difficult, but not impossible, to calculate an exact application rate. Each trigger sprayer model is designed for a specific application rate that is typically 1.2 ml/pull or in that range. We will flow rate test your intended trigger sprayer if possible and then document the amount applied per panel (typically ‘1 pull’ or ‘2 pulls’, depending on your needs).
For direct/contact spray applications, we generally use the same principles as reviewed above. If the product will be applied in a compressed air sprayer, we will apply at a moving speed that will approximate a given application such as 1 gal/1000 sq ft. If the product will be used in a trigger sprayer, we generally use 1 or 2 trigger pulls.
And lastly is the question of how to calculate for fogs, vapors, and other treatments for cubic space. For such products there are few industry standards to draw from. We offer chambers from 5.5 cubic foot to 6000 cubic foot, which allows us to dial in whatever size chamber you need. It is a simple calculation of the output rate of the applicator compared to the target volumetric application rate. Devices can include manually actuated aerosols, time-release aerosols, total release aerosols, smoke applicators, refillable cold foggers, refillable thermal foggers, and several more. Whatever your product, we can help you dial in your most efficient application rate. From there we can work on direct applications (i.e pests inside the chamber at the time of application) as well as residual applications wherein we place the target panel types inside the chamber during application and allow them to dry for a given time before we expose the pests to the dry panels. Ultimately, whatever your needs, we can help guide you through the maze of options.