For the last two years my hibiscus (Painted Lady) has experienced 100% bud drop in mid summer. Last year I thought it was the climate but this year I started to have some doubts. Sure enough, I put several yellowing buds into a ziplock and it appears I have gall midge (small yellow larvae are present.)
Advice I've found so far calls for a ground-based offensive (e.g. Triazicide) as well as an arial defense of spraying the plant. Is Sevin effective for spraying? Their label says it is, but I've yet to see it (or its active ingredients) recommended in the context of a hibiscus. I already have Sevin concentrate and would prefer to use it if it will be effective, but will buy something else if not.