The biology and pathology of dwarfmistletoe, Arceuthobium campylopodum F. abietinum, parasitizing true firs (Abies spp.) in California
| Authors: | R.F. Scharpf, J.R. Parmeter |
| Year: | 1967 |
| Type: | Technical Brief |
| Station: | Pacific Southwest Research Station |
| Source: | Tech. Bull. 1362. Washington, DC: U.S. Department of Agriculture, Forest Service. |
Abstract
Dwarfmistletoes (Arceuthobium spp.), considered the most important disease problem in California forests, cause extensive damage to coniferous timber species throughout the West. Reduction of the damage depends on adequate knowledge of the biology and pathology of these parasites. Much needed information is lacking, and many points of dispute remain concerning the behavior of dwarfmistletoes. Information about the parasites on true firs (Abies spp.) is particularly meager, for most studies of dwarfmistletoes have been made on other timber species.
Forest disease surveys conducted by the U.S. Forest Service have shown that about 30 percent of the white fir (Abies concolor (Gord. & Glend .) Lindi.) stands and about 40 percent of the red fir (A. magnifica A. Murr.) stands are infected with dwarfmistletoe (California Forest Pest Control Action Council 1961). Since true firs are heavily infected and constitute about one-fourth of the commercial timber volume in California information is urgently needed to provide a basis for controlling losses and directing future management of infected fir stands. Conequently, studies were undertaken to (a) collect information on the behavior of dwarfmistletoes on red fir and white fir, (b) compare this behavior with that of dwarfmistletoes on other hosts, (c) help clarify some of the disputed aspects of the biology and pathology of dwarfmistletoes, and (d) develop guidelines for use by forest managers in planning control projects.
In this report, the host-specialized members of Arceuthobium campylopodum Engelm. f. abietinum (Engelm.) Gill (Parmeter et al. 1960) are distinguished by referring to the particular host on which they occur; for example, red fir dwarfmistletoe, white fir dwarfmistletoe. This simplified naming system is used merely to eliminate any doubt as to hostparasite affinities.