Spruce budworms and relatives are a group of closely related insects in the genus Choristoneura. Most are serious pests of conifers. There are nearly a dozen Choristoneura species, subspecies, or forms, with a complexity of variation among populations found throughout much of the United States and Canada, and about again this number in Eurasia. Notable species are: Choristoneura fractivittana Eastern Spruce Budworm, Choristoneura fumiferana Mountain-ash tortricid, Choristoneura hebenstreitella… (More on Choristoneura)