Insect-Caused Cone and Seed Losses in Treated and Untreated Loblolly Pine Seed Orchards

摘要

Differences in strobilus survival and yields of viable seed were estimated between ramets of the same four clones of loblolly pine, Pinus taeda, in two differently managed seed orchards. One orchard had been treated with insecticides, fertilizers, and various cultural practices for a number of years, whereas the other orchard had not been treated with chemicals or cultural practices, other than mowing, for more than 8 years. During 1980, the webbing coneworm, Dioryctria disclusa, destroyed 33.5 percent of the second-year strobili in the treated orchard but not in the untreated orchard. The more intensive management practiced in the treated orchard resulted in increased strobilus production and survival as well as increased yields of viable seed per cone.