The Douglas-fir beetle (Dendroctonus pseudotsugae Hopkins) can kill large numbers of Douglas-fir trees (Pseudotsuga menziesii (Mirbel) Franco) across a landscape during periods of population outbreaks. High-value individual trees and small stands can be protected from Douglas-fir beetle infestation during outbreaks by applying the anti-aggregation pheromone, MCH (3-methylcyclohex-2-en-1-one). MCH treatments are...