Prominent diseases of gray pine include western gall rust (Periderium harknessii) and dwarf-mistletoe (Arceuthobium occidentale and A. campylopodum). Western gall rust forms galls on gray pine throughout its range but rarely causes serious damage. Dwarf-mistletoe is a particularly damaging and widespread disease. It infects trees of all ages, causing reduced tree vigor or death...Gray pine is the specific host for Ips spinifer. This bark beetle generally attacks fire- or drought-weakened trees. Heavy resin production by healthy trees provides a strong defense against most species of bark beetles.

Gray pine growing in hardpan is susceptible to windthrow under waterlogged soil conditions.

Fire effects: Gray pine is increasing in blue oak-gray pine communities due to fire suppression and lack of blue oak regeneration...Gray pine is highly flammable. The needles contain ether extracts. It is a heavy resin producer, with the wood, bark, cones, and needle sheaths all containing pitch. Congealed flows of resin that have dripped from wounds are common on gray pine. Consequently, it is susceptible to fire damage. Gray pine has two adaptations which enable it to survive fire. First, some large trees will withstand moderate-severity fire. Mature trees with thick bark and self-pruned trunks are best able to avoid fatal scorching. Secondly, seed regeneration is favored following fire. Fire creates a favorable bare mineral soil seedbed, and heat scarification of the woody seedcoat increases germination rates.