Armillaria Pathogenesis under Climate Changes

Abstract

Climate changes influencing forest ecosystems include increased air temperatures and CO 2 concentrations as well as droughts and decreased water availability. These changes in turn effect changes in species composition of both host plants and pathogens. In the case of Armillaria, climate changes cause an increase in the activity of individual species and modify the growth of rhizomorphs, increasing the susceptibility of trees. The relationship between climate changes and the biotic elements of Armillaria disease are discussed in overview.

Abiotic and Biotic Disturbances Affecting Forest Health in Poland over the Past 30 Years: Impacts of Climate and Forest Management

“…Potential increases in deciduous species (e.g., beech, oaks) may fail to materialize if trees are affected by disease, due to the occurrence of phytophthorosis of these species, as well as fungi of the genus Neonectria-causing bark damping and beetroot cracks, the activity of Armillaria spp., and wood boring beetles of the Agrilus genus, as recently observed in oak stands [60,65,[105][106][107][108][109][110]. On moist sites that are exposed to drought, hydric tree species (ash, alder, elm) will be exposed to adverse abiotic and biotic factors that may lead to a drastic decline in their condition or even large-scale dieback, for example due to Phytophthora spp.…”

“…In drought conditions, the negative impact of fungi that produce rhizomorphs (including Armillaria) will increase. Since rhizomorphs are capable of growing through the soil for long distances (many meters), they are better able to survive drought conditions by transporting water, carbohydrates, and minerals [105,[112][113][114]. In addition to changing tree species planted in such areas, activities should be undertaken to eliminate food sources of root pathogens (e.g., removing stumps and major roots of dead trees in affected areas).…”

“…As a result, there has been a high rate of spruce mortality, especially in the south of Poland. Bark beetles such as Ips typographus may be attracted to spruce trees whose roots are infected by Armillaria ostoyae, as the fungus can result in the foliage releasing certain chemical compounds [61,63,64,105]. In the coming years, biotic and abiotic factors affecting spruce forest health are likely to persist, and even greater rates of tree decline can be expected.…”

Responses of soil microarthropod taxon (Hexapoda: Protura) to natural disturbances and management practices in forest-dominated subalpine lake catchment areas

“…Considering the apparent importance of food resources, the high differences in proturan species abundances and their local distributions imply the existence of species-specific feeding preferences. In fact the dietary specialization can be more important driver of proturan distributions than the soil geochemistry and/or forest disturbances, which may act mostly as indirect drivers through their effects on ectomycorrhizal fungi and other decomposer rhizomorph producers 63 . Thus better knowledge of proturan feeding preferences might be the key to our understanding the importance of drivers underlying changes in distribution patterns of their assemblages.…”

Variability and Disturbances as Key Factors in Forest Pathology and Plant Health Studies

“…At the same time, emergent diseases are far from being in a stationary phase; climate change is currently affecting several pathosystems, especially where pathogens and/or hosts may be at the fringes of their natural or naturalized range [13]. For instance, Kubiak et al [14] point out that increasing temperatures will allow the root rot pathogens Armillaria spp. to grow all year round and to decay wood more effectively, thus significantly enhancing their spread rate and pathogenicity.…”