In the movie "The universal antidote" it was reported that bees were fed with CDS and became healthier and produced up to 50% more sucrose (dosed accordingly to their size of course). I think giving beetles CDS will only make them healthier (but that's just my guess. Whether it's really like that would have to be tested/researched...). Of course the dose could make a poison in this case but I don't think CDS is useful or advisable as a pesticide.
I would look more into permaculture. There, the goal is to create a natural balance between beneficial insects and pests so that they regulate themselves.
But there are also many plants that help against various pests. A few examples (I hope the plant names are translated correctly from german to english):
The common tansy: good against ants.
Polei mint: a slug repellent.
Lemon balm: good against ants and flies.
Castor bean: keeps moles away.
Pelagonia: good against mosquitoes.
Savory: good against pests.
Lavender: effective against wasps.
So if you have a slug problem, for example, you should just plant a few polei-mint plants between the infested lettuces (or whatever) to keep them away from your plants.
Because in the earth are also many microorganisms and bacteria at work that you would kill by CDS then probably partly. So you would disturb the natural cycle or intervene in it.
