Title: Forest insect and disease conditions in the United States 1979
Identifier: CAT31125142 (find matches)
Year: 1981 (1980s)
Authors: United States. Forest Service; Pronos, John, 1944-; Hoffard, Bill
Subjects: Insect pests United States
Publisher: (Washington, D. C. ?) : U. S. Dept. of Agriculture, Forest Service
Contributing Library: U.S. Department of Agriculture, National Agricultural Library
Digitizing Sponsor: U.S. Department of Agriculture, National Agricultural Library

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proximately 87 million cubic feet of volume loss. Fungi responsible for damage to commercial conifers in- cluded Phellinns weirii(Must.) Gilbertson, Armillariella mellea (Vahl ex Fr.) Karst., and Phaeoliis schweinitzii (Fr.) Pat. Needle casts. Lodgepole pine nee- dle cast, Lophodermella concolor (Dearn.) Darker, although locally severe in northern Idaho, was generally of light intensity in lodgepole pine in the remainder of the Region. Another needle cast, Lophoder- mella ara/«fa (Darker) Darker, caused severe defoliation of white bark pine on east side forests, par- ticularly in the King's Hall area of the Lewis and Clark National Forest. Discoloration of conifers caused by other needle pathogens remained static or declined. Most notable in the decline category was Meria nee- dle cast, Meria laricis Vuill., on western larch and Dothistroma nee- dle blight, Scirrhia pini Funk& A. K. Parker, on ponderosa pine. Douglas-fir needle blight, Rhab- docline weirrii, Parker & Reid. A needle pathogen occurred on Douglas-fir in the Libby and Colum- bia Falls areas of northwestern Mon- tana. Symptom development was similar to that of the common Christmas tree blight, which is nor- mally seen in the spring and early summer on the previous year's nee- dles. In this case, several age classes of needles were affected, and the symptoms were not seen until mid- fall. The pathogen is closely related to the Christmas tree blight fungus, Rhabdocline pseudotsugae Syd. Snow mold, Phacidium infestans Karst., on Douglas-fir was locally prevalent throught the Region for the first time. Initial symptoms were a bright yellowing or browning of older needles in the lower crown in March and April. Affected needles re- mained on trees throughout the sum- mer and turned brown or almost gray with several rows of small, dark brown fruiting bodies. Young trees In Region I, the dwurj mistletoes reduce growth by nearly 93 million cubic feet each year. with lower branches that had been covered by snow were most severely affected. Some growth loss, but little mortality, will result from infection. Winter damage to conifers was widespread in northern Idaho and western Montana. Areas with severe damage included Priest Lake, Bull Lake, Libby, upper Lochsa River, and lower Blackfoot River. Dis- coloration frequency and severity varied by area, microsite, and species. In order of decreasing susceptibility, trees affected were: western hemlock, western white pine, western red cedar, grand fir, pon- derosa pine, and Douglas-fir. Lodgepole pine, subalpine fir, and Engelmann spruce were seldom affected. Small trees in openings were most severely affected. Injury varied from a loss of a few needles to reddening of the entire crown. Unless other stress factors are imposed, most defoliated trees should recover the following sum- mer. Nursery diseases. At the Coeur d'Alene nursery, gray mold, Botrytis cinerea Pers. ex. Fr., caused widespread and nearly complete defoliation of 2-0 western larch. In most instances seedlings were not killed, but put on new foliage and developed normally. Loss estimates were unavailable. At the Coeur d'Alene nursery greenhouse and in other greenhouse operations in the Region, gray mold could be found causing defoliation, but apparently conditions necessary for serious losses were not reached. The most commonly affected species was western larch but a few 2 to 3 needle pines occasionally had girdled stems. Animal damage. Rodents girdled sapling-size western larch in thinned and unthinned stands on the Eureka Ranger Dis- trict, Kootenai National Forest, Mont. As many as 25 percent of the residual stems in thinned areas had dead tops.
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