i have a retaining wall built around my driveway which seems to attract wasps. i know for sure there are nests throughout the wall. the wall is built out of versa lock block . the wasps love to just congregate on the wall during the day which becomes a nuisance for friends and family. is there any type of product which i can spray over the entire wall to control and prevent. cypermethrin? and how often would the treatment need to be made since the wall is exposed to rain.
I use CYPERMETHRIN to effectively repel wasps and bees with residuals that last 3-4 weeks minimally. In some cases the results can be much better lasting 6-8 weeks. But this is when the climate is dry with no rain and little humidity. It’s also when I’m spraying on sealed surfaces (painted or plastic substrate) and from what I know of versa lock block, they tend to be quite porous.
If in fact they’re porous, I would say you could try the Cypermethrin but a better option for such surfaces would be something microencapsulated like the ONSLAUGHT. It can last a lot longer compared to any EC like Cypermethrin in general. But it’s also a lot less likely to get absorbed by porous surfaces like cement so that means you’ll end up with a lot more active ingredient where matters.