Pruning Dwarf Mistletoe Brooms Reduces Stress on Jeffrey Pines , Cleveland National Forest , California

ROBERT F. SCHARPF is projecllcader, forest disease research, with headquarters in Berkeley. Calif. He earned a bachelor's degree in forestry (1953) at the University of Missouri. and a master's degree in forestry (1957) and a doctorate in plant pathology (1963) at the University of California, Berkeley. He joined the Forest Service in 1960 and has been with the Station's staff since then. RICHARD S. SMITH is pathology group leader, Forest Pest Management. State and Private Forestry. Pacific Southwest Region, San Francisco. He earned a bachelor's degree (1958) in forest management from Utah State University, and a Ph.D. in plant pathology from the University of California. Berkeley (1963). He joined the Forest Service in 1961. DETLEV VOGLER is plant pathologist, with headquarters in San Francisco. He earned bachelor's (1965) and master's (1972) degrees from San Francisco State University, and a master's degree (1979) in plant pathology from the University of California, Berkeley. He joined the Forest Service in [973. ROBERT It. SCHARPF is project leader. forest disease research, with headquarters in Berkeley, Calif. He earned a bachelor's degree in forestry (1953) at the University of Missouri. and a master's degree in forestry (1957) and a doctorate in plant pathology (1963) at the University of California, Berkeley. He joined the Forest Service in 1960 and has been with the Station's staff since then. RICHARD S. SMITH is pathology group leader, Forest Pest Management, State and Private Forestry, Pacific Southwest Region, San Francisco. He earned a bachelor's degree (1958) in forest management from Utah State University, and a Ph.D. in plant pathology from the University of California, Berkeley (1963). He joined the Forest Service in 1961. DETLEV VOGLER is plant pathologist, with headquarters in San Francisco. Heearned bachelor's (1965) and master's (1972) degrees from San Francisco State University, and a master's degree (1979) in plant pathology from the University of California, Berkeley. He joined the Forest Service in 197). Western dwarf mistletoe (ArceUlhobium campylopodum Engelm.) has been recognized for years as a damaging disease organism of Jeffrey pine (Pinus jeffreyi Grev. & Bale) in southern California. On Laguna Mountain, Cleveland National Forest, for example, heavy mortality associated with dwarf mistletoe and insects threatens high value recreational areas. In the southwestern United States, research has shown that pruning the brooms off dwarf mistletoe infected ponder-osa pines (P. ponderosa Dougl. ex Laws.) increases vigor and reduces mortality considerably (Lightle and Hawksworth 1973). We studied the …