Depending on factors like moisture and wood species, how long can the destructive larval stage of the OHB last?

Answer

$2$ to $10$ years

The larval feeding period is extensive, often lasting several years, sometimes spanning from two up to ten years before the larva pupates.

Depending on factors like moisture and wood species, how long can the destructive larval stage of the OHB last?
insectwoodpestborerhouse borer