ASSOCIATION OF SCOLYTUS VENTRALIS (COLEOPTERA: SCOLYTIDAE) AND PHORADENDRON BOLLEANUM SUBSPECIES PAUCIFLORUM ON ABIES CONCOLOR

1971 ◽  
Vol 103 (12) ◽  
pp. 1697-1703 ◽  
Author(s):  
L. S. Felix ◽  
B. Uhrenholdt ◽  
J. R. Parmeter

AbstractAttacks by Scolytus ventralis on white fir were correlated both with periods of low precipitation and with medium to heavy infestations of true mistletoe. Trees were seldom attacked when the "running mean precipitation" was above 54 in. Attacks were significantly more frequent and were often a year or more earlier on trees with substantial amounts of mistletoe. Broods were seldom produced, however.Data suggest that heavy mistletoe infestation rendered trees more susceptible to beetle infestation, possibly by creating moisture stress in infected trees.

1974 ◽  
Vol 106 (3) ◽  
pp. 315-318 ◽  
Author(s):  
George T. Ferrell

AbstractXylem sap tension, an indication of moisture stress, was compared in foliated twigs of white fir infected by the mistletoe, Phoradendron bolleanum subspecies pauciflorum, and in paired, uninfected fir at the lower, mid-, and upper crown level. The upper boles were examined for fir engraver attacks. Reproductively successful attacks containing little or no host oleoresin were found in the infected fir, while only a single unsuccessful attack filled with oleoresin was found in the uninfected trees. Mean moisture stress in the upper crowns of most of the infected fir exceeded that in uninfected trees in all paired comparisons except one with a light infection. No differences in mean moisture stress between infected and uninfected trees were found at the lower and mid-crown levels.


1977 ◽  
Vol 55 (10) ◽  
pp. 1345-1350 ◽  
Author(s):  
Isabel F. Alvarez ◽  
Fields W. Cobb Jr.

Nine different types of mycorrhizae were observed on naturally occurring white fir seedlings in the north central Sierra Nevada, including one formed by the ubiquitous Cenococcum graniforme. The macro- and micro-scopic characteristics and reactions to different chemical reagents are described for five types. Possible mycorrhizal fungi of white fir are listed. Nursery-grown seedlings examined were ectomycorrhizal; intracellular penetration was not observed. None of the naturally occurring mycorrhizal types were found on nursery seedlings.


2007 ◽  
Vol 244 (1-3) ◽  
pp. 50-59 ◽  
Author(s):  
Jianwei Zhang ◽  
William W. Oliver ◽  
Martin W. Ritchie

1983 ◽  
Vol 115 (9) ◽  
pp. 1119-1127 ◽  
Author(s):  
R. R. Mason ◽  
T. R. Torgersen

AbstractCohorts of instar I larvae of the Douglas-fir tussock moth, Orgyia pseudotsugata, were stocked on branches of white fir, Abies concolor. Branches were either exposed naturally over drop-trays or protected with cages of nylon netting. Only 8.7% of the larvae in exposed cohorts survived to pupate, compared with 68.0% survival in caged cohorts where dispersal and predation were prevented. Losses from the exposed cohorts were caused mostly by arthropod predation, disappearance, and non-replaced dispersal. Disappearance of early larvae was attributed primarily to predation by spiders and insects while disappearance of late larvae was suspected to be due mostly to bird predation. In an analysis of k-values, actual or suspected predation accounted for 47.2% and dispersal 40.5% of the total loss.


1970 ◽  
Vol 102 (2) ◽  
pp. 175-181 ◽  
Author(s):  
Donald L. Dahlsten ◽  
E. Alan Cameron ◽  
William A. Copper

AbstractDouglas-fir tussock moth cocoons were collected and their distribution recorded by crown level on white fir, Abies concolor, in northeastern California. Nine trees were sampled in two defoliation classes, light (20–30% defoliated) and moderate to heavy (50–80% defoliated). Cocoons were more abundant in the lower crown levels as defoliation became greater. The proportion of female cocoons increased toward the lower levels of the crown. An overall sex ratio of 1.2♂:1.0♀ was recorded. Significantly more male cocoons were parasitized than female. A list of the natural enemies of the tussock moth from the study area is given.


Plant Disease ◽  
2002 ◽  
Vol 86 (11) ◽  
pp. 1274-1274
Author(s):  
R. Mathiasen

White fir dwarf mistletoe (Arceuthobium abietinum Engelm. ex Munz f. sp. concoloris Hawksw. & Wiens) is a serious and common pathogen of white fir (Abies concolor (Gord. & Glend.) Hildebr.), grand fir (A. grandis (Dougl. ex D. Don) Lindl.), and Low's fir (A. lowiana (Gord.) A. Murr.) in the western United States (1). In August 2002, this dwarf mistletoe was observed parasitizing mountain hemlock (Tsuga mertensiana (Bong.) Carr.) growing among severely infected grand fir near the trailhead to Cabot Lake in the Mount Jefferson Wilderness Area, Oregon at 44°34′27″N, 121°43′43″W, elevation 1,340 m. Only 2 of 27 mountain hemlocks observed in this area were infected. One tree had four infections, and one tree had two infections. Several fully developed male plants were found on one of the infected branches of mountain hemlock and were morphologically similar to those growing on the nearby grand fir. Other dwarf mistletoes that commonly parasitize mountain hemlock (Arceuthobium tsugense subsp. mertensianae and Arceuthobium laricis) were not observed in the area. In addition, white fir dwarf mistletoe can be distinguished from these mistletoes by its larger, yellowish shoots (1). Specimens of the mistletoe from mountain hemlock have been deposited in the Deaver Herbarium, Northern Arizona University, Flagstaff. To my knowledge, this is the first report of white fir dwarf mistletoe on mountain hemlock (1). Reference: (1) F. Hawksworth, and D. Wiens. Dwarf mistletoes: biology, pathology, and systematics. USDA Agric. Handb. 709, 1996


2012 ◽  
Vol 42 (6) ◽  
pp. 1178-1183
Author(s):  
William J. Otrosina ◽  
Stanley J. Zarnoch

We inoculated the fir engraver ( Scolytus ventralis LeConte) associated fungus Trichosporium symbioticum Wright onto 56 white fir ( Abies concolor (Gordon & Glend.) Lindl. ex Hildebr.) trees planted in a common garden study near Camino, California, that represented five geographic provenances of this species. The objective was to determine if there is a differential lesion length response of white fir provenances with respect to provenance. We found a significant (P < 0.019) difference between the provenances from Arizona and those of eastern Nevada origins 28 days after inoculation. There was a significant interaction between the two T. symbioticum isolates and season of inoculation. Fall inoculations tended to have smaller lesions than those in the spring but this varied by isolate in that the one from eastern Nevada tended to produce longer lesions in the spring (P = 0.0001) whereas the isolate from the Camino plantation did not differ between spring and fall (P = 1.000). There is evidence for genetic variability relative to white fir provenance lesion length in response to T. symbioticum inoculation, and in future studies, isolate variability should also be taken into account.


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