When defoliator outbreaks cover extensive areas, direct control should generally target large, continuous blocks for optimal results rather than small discrete blocks. Treatment of larger areas is more effective because it minimizes the risk of moth re-invasion and repeated egg deposition. The success of foliage protection tactics is measured by comparing the retention of foliage in treated and untreated areas. Long-term strategies to minimize damage caused by defoliators are accomplished through silviculture and treatment prescriptions. Long-term management tactics which can be implemented at the silviculture or treatment prescription stage are listed below.
Treatments followed by an asterisk are experimental in nature.
Where alternate species are not an option due to ecological constraints, difficulties in establishment, or economic factors, consider monitoring and modifications to stand tending and harvesting practices. Partial harvesting, thinning, or other similar treatments, should be carefully reviewed before any prescriptions are submitted or approved. These treatments may be appropriate for managing specific defoliators, but may compromise the integrity of the stand if root disease or other damaging agents are present. Long-term strategies should be considered for stands located in high and moderate hazard ecosystems. In Douglas-fir stands, patch infestations up to 250 hectares are characteristic.