Western Dwarf Mistletoe Parasitizing Colorado Blue Spruce and Norway Spruce in California

Western dwarf mistletoe (Arceuthobium campylopodum Engelm.), a common parasite of ponderosa pine (Pinus ponderosa Dougl. ex Laws.) and Jeffrey pine (Pinus jeffreyi Grev. & Balf.), was found parasitizing planted Colorado blue spruce (Picea pungens Engelm.) and Norway spruce (Picea abies (L.) H. Karsten) in Upper Cuddy Valley, CA (Kern County, T. 9 N., R. 21 W., Sec. 25). One tree greater than 6 m in height of each spruce species was infected and both trees were within 12 m of a Jeffrey pine severely infected with western dwarf mistletoe. Five to 10 branches were infected on each tree and a few of these had abundant mistletoe shoot production, which allowed identification of the parasite. This is the first report of western dwarf mistletoe on Colorado blue spruce. Although this is the first report of natural infection of Norway spruce in California, this mistletoe/host combination has been reported by Weir from artificial inoculation (2) and collected by Russell in central Washington (1). We recommend that these spruce species not be planted within 15 m of pines infected with western dwarf mistletoe. Specimens of western dwarf mistletoe on Colorado blue spruce and Norway spruce were collected and deposited at the Deaver Herbarium, Northern Arizona University, Flagstaff. References: (1) F. G. Hawksworth and D. Wiens. 1996. Dwarf Mistletoes: Biology, Pathology, and Systematics. USDA Agric. Handb. 709. (2) J. R. Weir. Bot. Gaz. 56:1, 1918.

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Southwestern Dwarf Mistletoe, Arceuthobium vaginatum subsp. cryptopodum, Found Parasitizing Picea pungens in Colorado

Plant Disease ◽

10.1094/pd-89-0106b ◽

2005 ◽

Vol 89 (1) ◽

pp. 106-106

Author(s):

R. Mathiasen ◽

N. Marcus

Keyword(s):

Pinus Ponderosa ◽

Ponderosa Pine ◽

Morphological Description ◽

Dwarf Mistletoe ◽

First Report ◽

Blue Spruce ◽

Northern Arizona ◽

Picea Pungens ◽

Voucher Specimens ◽

Pinus Spp

Southwestern dwarf mistletoe (Arceuthobium vaginatum (Willd.) Presl subsp. cryptopodum (Engelm.) Hawksw. & Wiens, Viscaceae) severely parasitizes several species of pines (Pinus spp., family Pinaceae) in Colorado, Utah, Arizona, New Mexico, and northern Mexico, but it has not been reported to parasitize any species of spruce (Picea, family Pinaceae) (1). However, in June 2004, this dwarf mistletoe was observed parasitizing blue spruce (Picea pungens Engelm.) in the Black Forest north of Colorado Springs, CO (39°02.118′N, 104°36.028′W, elevation 2,250 m). The infected blue spruce was planted as an ornamental approximately 4 m from a 16-m-high ponderosa pine (Pinus ponderosa Douglas ex Lawson & C. Lawson) severely infected with southwestern dwarf mistletoe. Mature dwarf mistletoe shoots were produced on five infected branches of the blue spruce. These shoots were compared with a morphological description of southwestern dwarf mistletoe (1) and this was sufficient for a positive identification of the dwarf mistletoe. The other dwarf mistletoes reported to infect blue spruce are Arceuthobium microcarpum (Engelm.) Hawksw. & Wiens, A. americanum Nutt. ex Engelm., and A. douglasii Engelm.; these are all morphologically distinct from southwestern dwarf mistletoe (1). Three of the infected branches formed small (less than 0.3 m in diameter), nonsystemic witches' brooms. All of the infections on the 6-m-high blue spruce were higher than 1 m on the tree. Thus, it is likely that the spruce was infected after it was transplanted. Three other blue spruces were also located within 4 m of the infected ponderosa pine, but these trees were not infected. To our knowledge, this is the first report of southwestern dwarf mistletoe parasitizing blue spruce and the first report of this dwarf mistletoe on Picea spp. Voucher specimens have been deposited in the Deaver Herbarium, Northern Arizona University, Flagstaff (Accession No. 73959). References: (1) F. Hawksworth and D. Wiens. Dwarf mistletoes: Biology, pathology, and systematics. USDA For. Serv. Agric. Handb. 709, 1996.

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First Report of Arceuthobium vaginatum subsp. cryptopodum on Pinus mugo

Plant Disease ◽

10.1094/pdis.2003.87.11.1395c ◽

2003 ◽

Vol 87 (11) ◽

pp. 1395-1395

Author(s):

R. Mathiasen ◽

M. Haefeli ◽

D. Leatherman

Keyword(s):

Pinus Ponderosa ◽

Ponderosa Pine ◽

Pinus Mugo ◽

Black Forest ◽

Dwarf Mistletoe ◽

First Report ◽

Northern Mexico ◽

Northern Arizona ◽

Positive Identification ◽

Northern Arizona University

Southwestern dwarf mistletoe (Arceuthobium vaginatum (Willd.) Presl subsp. cryptopodum (Engelm.) Hawksw. & Wiens, family Viscaceae) is a serious and common pathogen of ponderosa pine (Pinus ponderosa Douglas ex Lawson & C. Lawson) in Colorado, Utah, Arizona, New Mexico, and northern Mexico (1). In July 2002, this dwarf mistletoe was observed parasitizing a 1.4-m tall mugo pine (P. mugo Turra) in the Black Forest north of Colorado Springs, CO (39°02.118′N, 104°36.028′W, elevation 2,250 m). The infected mugo pine was planted as an ornamental approximately 6 m from a ponderosa pine infected with A vaginatum subsp. cryptopodum. Dwarf mistletoe shoots were produced on the only infected branch observed but this was sufficient for a positive identification of the dwarf mistletoe. Although J. Weir successfully inoculated mugo pine with western dwarf mistletoe (A. campylopodum Engelm.) and lodgepole pine dwarf mistletoe (A. americanum Nutt. ex Engelm.) (2), to our knowledge, this is the first report of a dwarf mistletoe occurring naturally on P. mugo, as well as the first report of A vaginatum subsp. cryptopodum on P. mugo (1). Specimens of A vaginatum subsp. cryptopodum from P. mugo have been deposited in the Deaver Herbarium, Northern Arizona University, Flagstaff (Accession No. 73761). References: (1) F. Hawksworth and D. Wiens. Dwarf mistletoes: biology, pathology, and systematics. USDA Agric. Handb. 709, 1996. (2) J. Weir. Bot. Gaz. 56:1, 1918.

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First Report of Arceuthobium hondurense on Pinus tecunumannii

Plant Disease ◽

10.1094/pdis.2000.84.3.372c ◽

2000 ◽

Vol 84 (3) ◽

pp. 372-372

Author(s):

R. Mathiasen ◽

J. Beatty ◽

J. Melgar

Keyword(s):

National Park ◽

East Side ◽

Dwarf Mistletoe ◽

First Report ◽

Northern Arizona ◽

Shoot Production ◽

Northern Arizona University ◽

Pinus Oocarpa ◽

Celaque National Park

Honduran dwarf mistletoe (Arceuthobium hondurense Hawksw. & Wiens) is a rare dwarf mistletoe found only in Honduras (1,2). Thus far, it has been reported to parasitize only Pinus oocarpa Schiede (2). In October 1999, we observed infection by A. hondurense on P. tecunumannii (Schw.) Eguiluz et Perry along the trail to the summit of Montana del Celaque (elevation 1,750 to 1,800 m) on the east side of Celaque National Park, ≈5 km west of Gracias (Department Lempira), Honduras. Infected pines had witches′ brooms, and mistletoe shoot production was common on infected branches. This is the first report of A. hondurense on P. tecunumannii. Specimens of A. hondurense from P. tecunumannii were collected and have been deposited at the Herbario, Escuela Nacional de Ciencias Forestales, Siguatepeque, Honduras, and at the Deaver Herbarium, Northern Arizona University, Flagstaff. References: (1) F. G. Hawksworth and D. Wiens. 1996. Dwarf Mistletoes: Biology, Pathology, and Systematics. U.S. Dep. Agric. Agric. Handb. 709. (2) R. Mathiasen et al. Phytologia 36:211, 1998.

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Mortality Associated with a Bark Beetle Outbreak in Dwarf Mistletoe-Infested Ponderosa Pine Stands in Arizona

Western Journal of Applied Forestry ◽

10.1093/wjaf/23.2.113 ◽

2008 ◽

Vol 23 (2) ◽

pp. 113-120 ◽

Cited By ~ 3

Author(s):

Shawn Kenaley ◽

Robert Mathiasen ◽

E. James Harner

Keyword(s):

Bark Beetle ◽

Pinus Ponderosa ◽

Ponderosa Pine ◽

Bark Beetles ◽

Basal Area ◽

Strong Relationship ◽

Dwarf Mistletoe ◽

Northern Arizona ◽

Stand Attributes ◽

Study Sites

Abstract Ponderosa pine (Pinus ponderosa Douglas ex C. Lawson var. scopulorum Engelm.) mortality was evaluated from a 2002 bark beetle outbreak in areas infested with southwestern dwarf mistletoe (Arceuthobium vaginatum [Willd.] Presl subsp. cryptopodum [Engelm.] Hawksw. & Wiens) in a total of nine study sites in northern Arizona. Ponderosa pine mortality attributable to bark beetles (Ips and Dendroctonus spp., Scolytidae) was systematically sampled, and stand attributes, such as basal area, tree density, dwarf mistletoe severity, and site indices were recorded. Ponderosa pine mortality was predominately attributed to Ips spp. Although the prolonged drought likely was the inciting factor responsible for the Ips spp. outbreak, results suggested a strong relationship between ponderosa pine mortality and the interaction between crown class and dwarf mistletoe rating class. Ponderosa pines severely infected with dwarf mistletoe and in the intermediate crown class are at the greatest risk of Ips spp. attack during outbreak years in northern Arizona.

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Germination, Establishment, and Mortality of Naturally Seeded Southwestern Ponderosa Pine

Western Journal of Applied Forestry ◽

10.1093/wjaf/18.2.109 ◽

2003 ◽

Vol 18 (2) ◽

pp. 109-114 ◽

Cited By ~ 14

Author(s):

Steven J. Stein ◽

Diana N. Kimberling

Keyword(s):

Pinus Ponderosa ◽

Ponderosa Pine ◽

Mineral Soil ◽

Mortality Data ◽

Mortality Factors ◽

Seedling Mortality ◽

Prescribed Burns ◽

Factors Affecting ◽

Northern Arizona ◽

Lepidopteran Larvae

Abstract Information on the mortality factors affecting naturally seeded conifer seedlings is becoming increasingly important to forest managers for both economic and ecological reasons. Mortality factors affecting ponderosa pine (Pinus ponderosa) seedlings immediately following natural germination and through the following year were monitored in Northern Arizona. The four major mortality factors in temporal order included the failure of roots to establish in the soil (27%), herbivory by lepidopteran larvae (28%), desiccation (30%), and winterkill (10%). These mortality factors were compared among seedlings germinating in three different overstory densities and an experimental water treatment. Seedlings that were experimentally watered experienced greater mortality than natural seedlings due to herbivory (40%), nearly as much mortality due to the failure of roots to establish in the soil (20%), less mortality due to winterkill (5%), and no mortality due to desiccation. The seedling mortality data through time were summarized using survivorship curves and life tables. Our results suggest that managers should consider using prescribed burns to decrease the percentage of seedlings that die from failure of their roots to reach mineral soil and from attack by lepidopteran larvae. West. J. Appl. For. 18(2):109–114.

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Verbenone Inhibits Attraction of Ips pini (Coleoptera: Curculionidae) to Pheromone-Baited Traps in Northern Arizona

Journal of Economic Entomology ◽

10.1093/jee/toaa192 ◽

2020 ◽

Vol 113 (6) ◽

pp. 3017-3020

Author(s):

Monica L Gaylord ◽

Stephen R McKelvey ◽

Christopher J Fettig ◽

Joel D McMillin

Keyword(s):

Aggregation Pheromone ◽

Pinus Ponderosa ◽

Ponderosa Pine ◽

Tree Mortality ◽

Treatment Options ◽

Current Treatment ◽

Northern Arizona ◽

Pine Engraver ◽

Baited Traps ◽

Significant Difference

Abstract Recent outbreaks of engraver beetles, Ips spp. De Geer (Coleoptera: Curculionidae; Scolytinae), in ponderosa pine, Pinus ponderosa var. scopulorum Engelm. (Pinales: Pinaceae), forests of northern Arizona have resulted in widespread tree mortality. Current treatment options, such as spraying individual P. ponderosa with insecticides or deep watering of P. ponderosa in urban and periurban settings, are limited in applicability and scale. Thinning stands to increase tree vigor is also recommended, but appropriate timing is crucial. Antiaggregation pheromones, widely used to protect high-value trees or areas against attacks by several species of Dendroctonus Erichson (Coleoptera: Curculionidae; Scolytinae), would provide a feasible alternative with less environmental impacts than current treatments. We evaluated the efficacy of the antiaggregation pheromone verbenone (4,6,6-trimethylbicyclo[3.1.1]hept-3-en-2-one) in reducing attraction of pine engraver, I. pini (Say), to funnel traps baited with their aggregation pheromone in two trapping assays. Treatments included 1) unbaited control, 2) aggregation pheromone (bait), 3) bait with verbenone deployed from a pouch, and 4) bait with verbenone deployed from a flowable and biodegradable formulation (SPLAT Verb, ISCA Technologies Inc., Riverside, CA). Unbaited traps caught no beetles. In both assays, baited traps caught significantly more I. pini than traps with either formulation of verbenone, and no significant difference was observed between the verbenone pouch and SPLAT Verb. In the second assay, we also examined responses of Temnochila chlorodia (Mannerheim) (Coleoptera: Trogositidae), a common bark beetle predator. Traps containing verbenone pouches caught significantly fewer T. chlorodia than the baited control and SPLAT Verb treatments. We conclude that verbenone shows promise for reducing tree mortality from I. pini.

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Stand density, drought, and herbivory constrain ponderosa pine regeneration pulse

Canadian Journal of Forest Research ◽

10.1139/cjfr-2019-0248 ◽

2020 ◽

Vol 50 (9) ◽

pp. 862-871 ◽

Cited By ~ 3

Author(s):

Thomas E. Kolb ◽

Kelsey Flathers ◽

John B. Bradford ◽

Caitlin Andrews ◽

Lance A. Asherin ◽

...

Keyword(s):

Pinus Ponderosa ◽

Ponderosa Pine ◽

Seedling Survival ◽

Stand Density ◽

Survival Duration ◽

Northern Arizona ◽

Growing Seasons ◽

Pine Regeneration ◽

Stand Thinning ◽

Survival And Growth

Trees in dry forests often regenerate in episodic pulses when wet periods coincide with ample seed production. Factors leading to success or failure of regeneration pulses are poorly understood. We investigated the impacts of stand thinning on survival and growth of the 2013 cohort of ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) seedlings in northern Arizona, United States. We measured seedling survival and growth over the first five growing seasons after germination in six stand basal areas (BAs; 0, 7, 14, 23, 34, and 66 (unthinned) m2·ha−1) produced by long-term experimental thinnings. Five-year survival averaged 2.5% and varied among BAs. Mean survival duration was longer in intermediate BAs (11 to 16 months) than in clearings and high BAs (5 months). The BAs of 7, 14, and 23 m2·ha−1 had >2600 5-year-old seedlings·ha−1. In contrast, regeneration was lower in the clearing (666 seedlings·ha−1) and failed completely in the 34 m2·ha−1 and unthinned treatments. Seedling survival was highest during wet years and lowest during drought years. Many surviving seedlings had no net height growth between years 4 and 5 because of stem browsing. Results indicate that natural regeneration of ponderosa pine is influenced by stand BA, drought, herbivory, and interactions between extreme climatic events.

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A Comparison of Wildlife Use in Broomed and Unbroomed Ponderosa Pine Trees in Northern Arizona

Western Journal of Applied Forestry ◽

10.1093/wjaf/19.1.42 ◽

2004 ◽

Vol 19 (1) ◽

pp. 42-46 ◽

Cited By ~ 7

Author(s):

Robert L. Mathiasen ◽

Gregg N. Garnett ◽

Carol L. Chambers

Keyword(s):

Ponderosa Pine ◽

Wildlife Habitat ◽

Passerine Birds ◽

Dwarf Mistletoe ◽

Erethizon Dorsatum ◽

Resting Sites ◽

Northern Arizona ◽

Wildlife Use ◽

Pine Trees

Abstract Dwarf mistletoe infections often induce structures known as witches' brooms that may provide an important wildlife habitat element. We compared evidence of wildlife use in broomed and unbroomed ponderosa pine trees at 12 mistletoe-infested sites in northern Arizona. We systematically sampled 12 broomed and unbroomed trees on each site (n = 144 broomed and 144 unbroomed trees) by climbing and inspecting each tree to document evidence of wildlife use. Broomed trees were used more frequently than unbroomed trees for wildlife activities including foraging/caching, nesting, and roosting/resting sites. We observed evidence of use by Abert squirrel (Sciurus aberti), porcupine (Erethizon dorsatum), and passerine birds in witches' brooms. Of the 226 brooms we examined, 23% (n = 52) contained evidence of wildlife use. Mammal use was found in 80% (n = 42) of the brooms and of these, 39 were used by Abert squirrel. We recommend that management agencies consider retaining some of these broomed trees to provide habitat for wildlife. West. J. Appl. For. 19(1):42–46.

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Dwarf mistletoe effects on fuel loadings in ponderosa pine forests in northern Arizona

Canadian Journal of Forest Research ◽

10.1139/x06-259 ◽

2007 ◽

Vol 37 (3) ◽

pp. 662-670 ◽

Cited By ~ 17

Author(s):

Chad Hoffman ◽

Robert Mathiasen ◽

Carolyn Hull Sieg

Keyword(s):

Ponderosa Pine ◽

Fire Behavior ◽

Fuel Loading ◽

Dwarf Mistletoe ◽

Forest Fuels ◽

Ponderosa Pine Forests ◽

Northern Arizona ◽

Basaltic Soils ◽

Four Levels ◽

Fuels Treatments

Southwestern dwarf mistletoe ( Arceuthobium vaginatum (Willd.) J. Presl ssp. cryptopodum ) infests about 0.9 million ha in the southwestern United States. Several studies suggest that dwarf mistletoes affect forest fuels and fire behavior; however, few studies have quantified these effects. We compared surface fuel loadings and predicted fire behavior among four levels of dwarf mistletoe infestation (none, light, moderate, and severe) in a total of 239 plots on 11 sites on basaltic soils in northern Arizona. In each plot we measured tree attributes, dwarf mistletoe rating and surface fuel loading. Stands severely infested by dwarf mistletoe had lower (P < 0.05) tree density and higher snag density, but higher (P < 0.05) total surface fuel loadings and total fuel loadings >7.62 cm and <7.62 cm, than non-infested stands. However, there were no statistical differences in any canopy fuel variables among infestation classes. Predicted fire behavior indicated that the wind speed required to promote the spread of a surface fire into the canopy was lower in severely infested stands than in non-infested stands. These results suggest that stands in northern Arizona that are severely infested with dwarf mistletoe should be priority areas for fuels treatments.

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