There are a few spots in siding where you can successfully introduce insecticides.
How to seal siding from bugs.
Seal small cracks and gaps in your siding under 1 4 inch wide using an acrylic latex caulk.
I take advantage of these tiny holes using pyrethrin aerosols and an injection straw.
I d use dusts but the ready made hole is far to small.
Simply apply this inexpensive filler into the cracks to seal.
Caulk is cheap easy to apply and can go a long way towards keeping bugs out.
First vinyl siding has tiny weep holes at the bottom of each course panel to allow moisture to escape.
Instead i d probably just let the siding thoroughly dry in the sun checking for signs of bugs during that time then go ahead and use it.
Paint works well over it.