Aug 01, 2022 - 09:06 AM
This type of wording on pesticide labels is becoming more and more common. Basically, the fear is that by applying to cement surfaces outdoors, rain can wash it into storm drains and therefore contaminate, pollute or "contribute" to high pesticide levels in lakes.
Pesticides, fertilizers, even grass clippings all contribute to lake and water supply pollution. Not only does it effect wildlife such as fish, these things can make a lake unsuitable for even swimming, much less being a source of drinking water. Individually, there may not be any issue, but over the broad range of a city of county, the effect on a lake can be tremendous.
Spraying directly on cement can also be a waste of product, as it needs to be applied directly where insects live and breed.
Hope this helps.