Hi,
Thanks for your question. Here's what I found on treating your trees for Mountain Pine Beetle.  
Certain formulations of carbaryl (Sevin and others) permethrin (Astro, Dragnet and others), and bifenthrin (Onyx) are registered for use to prevent attacks on individual trees. These sprays are applied to living green trees in early summer to kill or deter attacking beetles. This preventive spray is generally quite effective through one MPB flight (one year).

Without knowing what other pests you are trying to control I am unable to answer more than that. Insects will be treated and/or prevented based on their life cycle, some are treated in their egg stage, some as larvae and some as adults.

Here are a few general articles about insect control:
https://extension.colostate.edu/topic-areas/insects/insect-control-horticultural-oils-5-569/
https://extension.colostate.edu/topic-areas/insects/insect-control-soaps-and-detergents-5-547/
https://extension.colostate.edu/topic-areas/insects/insect-parasitic-nematodes-5-573/