Characterization of Fungal Pathogens Associated with White Pine Needle Damage (WPND) in Northeastern North America

Abstract

Abstract:Eastern white pine is a crucial ecological and economic component of forests in the northern USA and eastern Canada, and is now facing an emerging problem in white pine needle damage (WPND). It is still unclear whether WPND results from one, or the combination of several fungal pathogens. Therefore, the first objective of this study was to characterize the fungi associated with WPND in the northeastern United States and document the damage being done to mature eastern white pine as a result of repeated defoliation. To date, 22 species of fungi, either cultured from diseased pine needles or formed fruiting bodies on pine needles were identified based on morphology and sequence data. Lecanosticta acicola and a putative new species of Septorioides were the species most frequently recovered from diseased needles, in addition to needle cast fungi Lophophacidium dooksii and Bifusella linearis, two obligate fungal pathogens that were frequently observed on pine needles in the northeast, but have not been known to cause excessive defoliation of eastern white pine. A second objective was to monitor yearly the health of 63 pairs of healthy and unhealthy trees in eight affected locations throughout New England. Since 2012, affected trees are increasingly and repeatedly chlorotic and defoliated every year. Trees that were initially healthy are now exhibiting symptoms. While L. acicola appears to be the primary pathogen causing WPND, several other common needle pathogens are being more frequently observed and the role of climate change may be important in the disease ecology of WPND. These defoliation events, while once a sporadic occurrence, have now become OPEN ACCESSForests 2015, 6 4089 more frequent as observed in continued crown deterioration of eastern white pine in long-term monitoring plots followed during the course of this three-year study.

Lecanosticta acicola: A growing threat to expanding global pine forests and plantations

“…These brown spots can also appear resin‐soaked depending on the host species (Skilling and Nicholls, ). In some cases, as has been reported in P. strobus , symptoms may only be displayed as chlorosis of the needles without banding (Broders et al ., ). Infected needles die from the apex to the base (Fig.…”

“…Here it can result in mortality reaching 50% and higher in the southeastern USA (Cordell et al, 1990). New reports of L. acicola causing damage on P. strobus have emerged since 2005 in the northeastern USA and Canada and these have been attributed to changes in pre cipitation and climate in the regions (Broders et al, 2015;Wyka et al, 2017Wyka et al, , 2018. Lecanosticta acicola is also recognized as a component of a complex of pathogens that cause white pine needle damage (WPND) in this region (Broders et al, 2015).…”

“…Lecanosticta acicola has been wellknown in the southeastern USA since the early 1900s, but is rapidly spreading in northern parts of the USA, Canada and in some parts of Europe (Broders et al, 2015). Its complete host range is not known but appears to be expanding (Mullett et al, 2018).…”

Isolation and identification of Sydowia polyspora and its pathogenicity on Pinus yunnanensis in Southwestern China

“…Moreover, this fungus can increase the severity of Dothistroma needle blight in Pinus ponderosa Laws. and may be associated with white pine needle damage (WPND) in Northeastern America (Broders, Munck, Wyka, Iriarte, & Beaudoin, ; Ridout & Newcombe, ). In China, S. polyspora reported as Sclerophoma pithyophila (Corda) Höhn.…”

Extent and Severity of Caliciopsis Canker in New England, USA: An Emerging Disease of Eastern White Pine (Pinus strobus L.)

“…Based on the morphological and ecological description of the type specimen we feel confident the isolates sequenced for this study represent C. pinea as described in the original investigation of the species as well as other early investigations on this fungus [4,12]. The ITS gene of six isolates of C. pinea were amplified using polymerase chain reaction and sequenced using primers ITS1F and ITS4 that amplify fungal DNA from the internal transcribed spacer (ITS) regions 1 and 2 according to methods developed previously for molecular identification of P. strobus pathogens [19], and were deposited in GenBank (Accession numbers still to come from GenBank). As there were no ITS sequences for C. pinea in GenBank, the ITS sequences for closely related species of Caliciopsis and Corynelia were imported from GenBank and included in a phylogenetic analysis to understand the relationship of C. pinea to other members of the Coryneliales.…”