Hexane extracts of spruce budworm, Choristoneura fumiferana, moth scales, applied at 0.04 moth-gram equivalents/branch and at 0.06 moth-gram equivalents/tree, failed to increase parasitism rates of Trichogramma spp. in two cutover spruce-fir stands in Maine. Releasing "Maine-strain" T. minutum apparently increased parasitism rates about 20-fold. However, application of kairomone extracts to whole branches and to upper crowns of small trees may have interfered with host-searching behaviors of Trichogramma parasitoids.
Jennings, Daniel T. and Jones, Richard L.
"Field Tests of Kairomones to Increase Parasitism of Spruce Budworm (Lepidoptera: Tortricidae) Eggs by Trichogramma Spp. (Hymenoptera: Trichogrammatidae),"
The Great Lakes Entomologist, vol 19
Available at: https://scholar.valpo.edu/tgle/vol19/iss3/9