Get a fanbased electric trap... They suck at flying, so will easily be caught up in it.
- For the larva, if you can get some diatomaceous earth and pour a tiny layer on top of the soil, it should take care of it, and pretty much any other pest landing on or burrowing into the soil. (diatomaceous earth is silica based rocks grinded into powder.. It's absolutely brilliant for pest control, as it enters every crack it can, and drains the insects of fluid. - I use it for everything pest related. lol.. Also, it's "food grade", and can essentially be eaten, but don't...)