Four types of spruce budworm pheromone lures were field-tested in sparse spruce budworm populations in Maine. BioLures® with constant pheromone emission rates less than 1.0, ca. 1.0-1.5, and ca. 15.0 micrograms of pheromone per day were compared to polyvinyl chloride (PVC) lures with rapidly decreasing pheromone emission rates. Mean trap catch was roughly proportional to lure emission rates. All lures continued to catch moths over the entire flight period but moth catches with the three lowest emission-rate lures were judged to be too low. BioLures with the highest emission rate (15.0 micrograms of pheromone per day) showed the lowest variability in trap catch and the fewest zero trap catches.
Grimble, David G.
"Pheromone Lures to Monitor Sparse Populations of Spruce Budworm, Choristoneura Fumiferana (Lepidoptera: Tortricidae),"
The Great Lakes Entomologist, vol 21
Available at: https://scholar.valpo.edu/tgle/vol21/iss4/1