Unless you have an aphid infestation, sadly your ladybugs are going to die of starvation.
Misting your plants twice a day is unnecessary, they will be getting enough nutrition from the roots.
Besides, the fertilizer misting is only needed if there needs to be a quick fix due to a health issue and misting healthy plants with fertilizer just burns the leaves as you have found out. It can, if done excessively, also clog the stomata/leaf pores and hinder transpiration, which will effect over all pant health.
There are no short cuts when growing, patience is your best friend when cultivating cannabis.
Hope this helps,..........
Organoman.