Insect Infestation That Can Harm Your Ornamental Pacific Silver Fir

14 January 2016
 Categories: , Blog

The pacific silver fir is a beautiful ornamental evergreen that grows wild along the western coast of North America. Pacific silver firs have a gray, papery bark that becomes more furrowed over time and needle-like leaves that have a fresh scent. If you live on the west coast and want an ornamental alternative to a traditional fir, the pacific silver fir might be a good choice for you.

Part of responsible tree ownership is learning what insects could threaten your new tree. There are a few different pests that target the pacific silver fir and knowing the signs of infestation and calling in a tree service or pest control company could save the life of your tree.

Douglas-Fir Tussock Moth

Douglas-fir tussock moths are either multi-toned brown (males) or gray and flightless (female). The larvae are multi-colored caterpillars that emerge during the late spring season, which corresponds to the newer foliage appearing on the tree. The larvae will eat that foliage and create defoliation usually from the top of the tree downwards.

If you suspect a moth infestation, call in a pest control company for proper diagnosis and immediate pesticide treatment. Moths can continue to defoliate the tree and weaken the pacific silver fir so that it becomes vulnerable to more fatal types of infestations.

Balsam Woolly Adelgid

The balsam woolly adelgid is a fuzzy white insect that is largely immobile and simply sits in one spot sucking up tree nutrients. Pacific silver firs are relatively resistant to these pests, which means the tree can become infested, but the adelgids are unlikely to cause any major damage. The most likely symptom is some excessive shedding of needles.

A pest control or tree service can spray pesticides to kill off the adelgid population. Call immediately for spraying if you have any nearby Fraser firs as those trees can be killed by an adelgid infestation.   

Fir-Engraver Beetle

Fir-engraver beetles are small, black beetles that are fatal to pacific silver firs. The name comes from the fact that the female beetles bore a narrow trench in the bark into which the eggs are laid. Larvae then emerge a couple of weeks later and start snacking on the inner tree flesh and vital vascular system.

A fir-engraver beetle infestation will cause die-back to start at the top of the crown and move downward. The only way to protect other firs in the area is to hire a tree removal company to completely cut down the pacific silver fir. There aren't any insecticides that work on the fir-engraver.

If you have a new pacific silver fir, regular maintenance to prune away damaged branches and to keep soil well fertilized can prevent the infestation from happening in the first place. To learn more, speak with someone like B. Haney & Sons.