When the service technician vacuumed out the PVC condensate drain line for my heat pump, a lot of bugs and slugs came out. He told me this was not uncommon and that he's even found nakes in there. So I inserted a small wire-mesh sink-drain strainer into the wide end of a ¾-to-1-inch PVC adapter and held the strainer in place with silicone adhesive. The adapter's small end fits onto the drain line without glue, allowing the technician to pop it off and clean it. No more bugs, no more slugs.
Don Elgin, Belton, SC