European pine shoot moth (Rhyacionia buoliana)
U.S. Department of Agriculture, Forest Service. 1979. A guide to common insects and diseases of forest trees in the northeastern United States. Northeast. Area State and Private Forestry, Forest Insect and Disease Management., Broomall, PA. p. 123, illus.(USDA Forest Service, Northeast Area State and Private Forestry Publication. NA-FR-4)
Red, mugho, Scots and Austrian pines are the preferred hosts of this shoot moth, but damage has been recorded on Japanese red, Japanese black, ponderosa, eastern white, jack, pitch, longleaf, and Virginia pines. Young, open-grown pines less than 25 feet tall are most susceptible to attact and damage. Crown closure controls infestations.
The most significant damage occurs in the spring, when larvae tunnel the shoots. Weakened shoots sometimes bend but continue growing, resulting in crooked stems and branches called "post horns." When buds are destroyed, dead or spike tops are produced. Adventitious buds often form below the dead portion, and dense, bushy top growth results the following season.
Moths emerge in June and July and lay eggs on new needles. Young larvae spin resin-coated webs between the needle sheaths and stems of the current year's growth. Early feeding occurs within the sheath at the base of needles. In midsummer, the larvae move to the buds; feeding ceases in August, and the larvae overwinter in resin-coated webs at the bases of buds. In spring, larvae move to undamaged buds or new shoots, where they complete their feeding. The mature larvae are light brown with no distinct lines or other markings. The head, prothoracic shield, and anal plate are black. Pupation takes place during summer in the dead buds and shoots. Adults emerge in about 14 days, leaving the empty pupal cases extending from pupal chambers in the hollowed-out buds. One generation occurs each year.