A new review article looks at 40 years of research and development of a leading method for protecting Douglas-fir trees from infestations by Douglas-fir beetles (Dendroctonus pseudotsugae), using the pests’ antiaggregation pheromone against them—essentially putting up a “no vacancy” sign that sends the beetles elsewhere. (Photo by Lindsey Seastone, USDA APHIS PPQ, Bugwood.org)