hyd.peroxide ,i used it in a promix/soil mix , just poured it all over on the soil. as far as using it in coco/peat , i dunno , maybe someone on here has but i don't think it'd be any different than my soil mix though.
food grade diatomaceous earth , sprinkle some lightly on top of soil and then wait , them effers slowly disappear. with a bad infestation outdoors i had to use hydrogen peroxide [kills larvae] at 50/50 water/hp. both methods have worked well for me so far , good luck !