Root Pathogen Complexes in Pacific Northwest Forests

Goheen, Donald J.; Filip, Gregory M.

doi:10.1094/pd-64-793

Cited by 3 publications

(5 citation statements)

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“…For a concise survey of the most common diseases and insects affecting inland Pacific Northwest forests, we refer the reader to Goheen and Willhite (2006), and recommended references therein. Four tree-killing root diseases naturally occur in MMC forests: laminated root rot, caused by Phellinus weirii; Armillaria root disease, caused by Armillaria ostoyae; and both the P-and S-type annosum root diseases (formerly Heterobasidion annosum, now H. irregular and H. occidentale, respectively) (Filip 1990;Goheen 1982, 1984;Goheen and Filip 1980;Hadfield et al 1986). Root diseases were common (<5 to 10 percent of patches affected) but not dominant in most presettlement-era MMC forests, where they provided structural diversity within patches and enhanced heterogeneity in size of openings, amount and shape of edge, and size of patches.…”

Section: Diseases-mentioning

confidence: 99%

“…Refugia were found in shaded draws, on cool north slopes, in riparian areas and stream confluence zones (Camp et al 1997), and adjacent to rock outcroppings and talus slopes, where fires burned with difficulty. This pathogen also overwhelmed low-vigor, mature, weakened, and injured trees, and those stressed by drought or lightning strike, scorched by fire, or attacked by other root pathogens Goheen 1982, Goheen andFilip 1980). Thus, it is fairly common to find more than a single root pathogen colonizing trees.…”

Section: Diseases-mentioning

confidence: 99%

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Historical forest changes in the western United States

Loehle

2020

The Forestry Chronicle

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Changes in factors such as temperature, precipitation, fire regimes, ozone, atmospheric CO2, and nitrogen deposition may have altered forest growth over the past century. Determining changes in forest growth over long intervals is complicated by constantly changing growing conditions due to tree maturation, stand self-thinning, disturbance, and other factors. Because a comprehensive review is lacking, results from publications examining forest growth trends in the western United States over the past 100 years were evaluated. Across the region, upper elevational forest ecotones have been expanding upward in many but not all locations, possibly due to warming and reduced snowpack. Across most of the region, both growth increases and decreases are localized and spatially dispersed. For the inland West, historical photography and long-term inventory data show clear densification and expansion of ponderosa pine (Pinus ponderosa) and mixed conifer forest across the region, mostly due to reduced fire incidence. However, a recent drought, probably linked to ocean cycles and exacerbated by warming, has caused a growth setback and mortality, especially in the Southwest. Forest densification due to altered fire regimes does not equate to enhanced growth per se. Aspen (Populus tremuloides) dieback has been noted due to recent drought and local conifer mortality caused by drought has also been documented in several locations. Regeneration after recent fires appears to be inadequate in many localities. Except for local increased growth at some high elevation and coastal sites and possible periodic drought effects in the Southwest, it is difficult to detect any growth trends with available data.

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Section: Diseases-mentioning

confidence: 99%

Section: Diseases-mentioning

confidence: 99%

Historical forest changes in the western United States

Loehle

2020

The Forestry Chronicle

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“…It is considered one of the five most damaging root diseases in western forests (Hadfield et al 1986) and is widespread across much of the range of its hosts, but incidence and severity, and thus the importance to forest management, vary greatly (Ferguson 2009). Because L. wageneri is an insect-vectored pathogen and the vectors are generally attracted to weakened trees, this fungus often occurs in complexes with other root disease fungi (Filip and Goheen 1982b;Goheen and Filip 1980;Morrison and Hunt 1988). It has been found colonizing the same roots of Douglas-fir as Armillaria ostoyae (Byler et al 1983;Goheen and Hansen 1978;Morrison and Hunt 1988), Phellinus sulphurascens (Filip and Goheen 1982b;Goheen and Filip 1980;Morrison and Hunt 1988;Witcosky 1989), and a Heterobasidion species (Kelsey et al 1998).…”

Section: Biology and Ecologymentioning

confidence: 99%

“…Because L. wageneri is an insect-vectored pathogen and the vectors are generally attracted to weakened trees, this fungus often occurs in complexes with other root disease fungi (Filip and Goheen 1982b;Goheen and Filip 1980;Morrison and Hunt 1988). It has been found colonizing the same roots of Douglas-fir as Armillaria ostoyae (Byler et al 1983;Goheen and Hansen 1978;Morrison and Hunt 1988), Phellinus sulphurascens (Filip and Goheen 1982b;Goheen and Filip 1980;Morrison and Hunt 1988;Witcosky 1989), and a Heterobasidion species (Kelsey et al 1998). and Hylastes porculus Erichson, which feed on freshly cut stumps and the lower stems and roots of red pine and carry the fungi into the lower stem and root system (Erbilgin and Raffa 2002;Klepzig et al 1991).…”

Section: Biology and Ecologymentioning

confidence: 99%

Forest root diseases across the United States

Lockman¹,

Kearns²

2016

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“…In addition, the root system is reduced with the appearance of sores and rot sometimes making the roots appear brown and spongy, especially in the crown of some conifer species. These oomycetes are also involved in negative plant-soil feedback due to monoculture and replanting problems of apple orchards [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Phytopythium vexans Associated with Apple and Pear Decline in the Saïss Plain of Morocco

et al. 2021

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An extensive survey conducted in the Saïss plain of Morocco during the 2017–2018 growing season revealed that 35 out of 50 apple and pear orchards were infested with a pathogen that causes the decline disease. Morphological and phylogenetic tree analyses using the cox II gene allowed us to identify the pathogen as Phytopythium vexans. Interestingly, no Phytophthora and Pythium species were isolated. The occurrence and prevalence of the disease varied between locations; the most infested locations were Meknes (100%), Imouzzer (83%), and Sefrou (80%). To fulfill Koch’s postulate, a greenhouse pathogenicity test was performed on the stem and collar of one-year-old healthy seedlings of apple rootstock M115. Symptoms similar to those observed in the field were reproduced in less than 4 months post-inoculation with root rot disease severity ranging from 70 to 100%. The survey results evidenced that apple rootstocks, soil type, and irrigation procedure may contribute significantly to the occurrence of the disease. The disease was most prevalent in drip water irrigation and sandy-clay soil on wild apple rootstock. Accordingly, a rational drip advanced watering system and good sanitation practices could eliminate water stagnation and help prevent the onset of this disease. It was concluded that Pp. vexans occurrence may be strongly influenced by irrigation mode and type of soil. Therefore, the obtained findings of this study could help to better understand the recurrence of this disease and to develop a reliable integrated strategy for its management.

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Root Pathogen Complexes in Pacific Northwest Forests

Cited by 3 publications

References 0 publications

Historical forest changes in the western United States

Historical forest changes in the western United States

Forest root diseases across the United States

Phytopythium vexans Associated with Apple and Pear Decline in the Saïss Plain of Morocco

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