Forests pests cost national government millions and local governments billions of dollars annually. They cost homeowners millions of dollars in treatment (and tree removal) and negatively impacts property values by millions annually. While preventative treatment is expensive, it is more affordable than the aftermath of forest devastation.
National Economic Cost Estimates by Insect Feeding Guild
Annualized marginal damages
Adapted from: Aukema et al. 2011. PLoS One Vol. 6: 1-7