Dieback and mortality of plantation Japanese larch (Larix kaempferi) associated with infection by Phytophthora ramorum

Abstract

The invasive pathogen Phytophthora ramorum is the cause of 'sudden oak death', a dieback and mortality of more than one million live-oak and tanoak trees along 1500 km of near-coastal native forest in California and Oregon since 1995 (Rizzo et al., 2002; Frankel, 2008 (Fig. 4)

Integrating natural and social science perspectives on plant disease risk, management and policy formulation

“…However, subsequent findings of P. ramorum on bilberry (Vaccinium myrtillus) in heathland and in Japanese larch (Larix kaempferi ) plantations in Britain in 2009 both heightened the threat and broadened the disease context. The findings on Japanese larch [61] were the first observations on a commercial tree species, where areas of mass infection and spread to neighbouring host plants had been observed. The experience with sudden oak death in the USA would suggest that such a source of infection may undermine attempts to eradicate the disease in nearby nursery holdings.…”

Sudden Oak Death: Interactions of the Exotic Oomycete Phytophthora ramorum with Naïve North American Hosts

“…Unlike many other forest phytophthoras (reviewed in reference 58), it is comprised not only of distinct populations but of multiple evolutionary phenotypically distinct lineages (8,36,66,67,117), which have evolved in isolation for hundreds of thousands of years (22,49,51,81,101). Lineages are not uniformly distributed in North America and Europe, and the pathogen is still adapting to new habitats and hosts, as evidenced by the emergence of sudden larch death (11,122). Furthermore, P. ramorum causes at least three types of disease (lethal cankers, leaf and branch dieback, leaf blotches or spots) on different hosts.…”

Tree disease and pest epidemics in the Anthropocene: A review of the drivers, impacts and policy responses in the UK

“…This included money for an extensive programme of clearance of rhododendron understorey in private woodland throughout the country in an attempt to remove one of the disease's main sporulating host species. It was at this point, in autumn 2009, that the outbreak entered a new and more critical phase following the discovery of the disease infecting a large number of Japanese larch (Larix kaempferi) trees in South West England, an important forestry tree which accounts for almost 10% of the conifer growing area of Britain Webber et al 2010). For the first time, the disease had been found killing a commercially important conifer species anywhere in the world and by July 2010 an estimated 1,900 ha of larch plantations (about half a million trees) were showing signs of infection .…”