Sorry, wrong pesticide. Permethrin is for tick protection sprayed on clothing, Pyrethrin is for the gus beetles.

I just hand pick and drop in bucket of soapy water. You can just wipe the eggs off the plants with your fingers. If its a really bad infestation I spray with Neem but it can kill beneficials too so its a last defense and rarely used. I never use Pyrethrin but I'd suspect that yes, you'd have to do a follow up spraying since it is a contact-only pesticide.

Dave

Thanks Dave

I did start to handpick and squash but when I picked one off several of the others on the same fern would bail off into the mulch. I guess now that I knocked out the adults I might be able to manage flicking them into soapy water if there are not so many.