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

Abstract

Caliciopsis canker is an emerging problem in Pinus growing regions of Eastern North America. The fungal disease caused by Caliciopsis pinea is associated with overstocked stands and poor sites, but few quantitative data are available. The objective of this study, therefore, was to assess the extent and severity of Caliciopsis canker and to explore environmental variables associated with disease to identify areas at risk of damage. During 2014, 58 sites across New England with >75% P. strobus basal area in public lands were surveyed. Most sites (72%) had Caliciopsis canker signs or symptoms. Caliciopsis pinea was successfully identified with molecular techniques. In sites with Caliciopsis canker, 36% of the mature pines were symptomatic. Pole sized and suppressed trees were more likely to be damaged than larger trees with dominant crown positions OPEN ACCESSForests 2015, 6 4361 (p < 0.05). Pinus strobus density for sites with Caliciopsis canker was 311 trees/ha (mean P. strobus stand diameter = 40 cm) compared to 220 trees/ha (mean white pine stand diameter = 43 cm) for sites without Caliciopsis canker (p = 0.1). Caliciopsis canker symptoms tended to appear more frequently in stands with excessively drained, coarse textured soils derived from glacial outwash (86%) or stands with poorly drained soils and low fertility (78%) than in stands with well drained, more fertile soils (59%) (p = 0.1). The severity of symptoms varied among soil groups and was greater for excessively drained, nutrient poor soils than for well-drained, more fertile soils (p = 0.027).

Soil and Stocking Effects on Caliciopsis Canker of Pinus strobus L.

“…Wingf.) have been associated with white pine cankers [6,7]. The pathogenicity of C. pinea to eastern white pine was demonstrated by Ray in 1936 [8].…”

“…The sites visited during 2015 were sawtimber (mean stand diameter at breast height, 1.3 m from the ground: DBH > 23 cm) stands because most of the eastern white pine resource in New England is mature and these site were randomly selected. Previously, Caliciopsis canker symptoms were more frequently observed on pole-size trees (DBH = 11.5-22.9 cm) [6]. In addition, during 2015, Caliciopsis cankers and fruiting bodies were frequently observed on white pine regeneration ( Figure 1).…”

Detection and quantification of the air inoculum of Caliciopsis pinea in a plantation of Pinus radiata in Italy

“…Although C. pinea triggered damages on P. strobus in the 1930s and some epidemiological studies were conducted in North America (Ray 1936, McCormack 1936, it has arisen scientific attention only in 2009 as a result of unexpected serious damages on P. strobus forests throughout several north-eastern US states (Munck et al 2015(Munck et al , 2016. In Europe, it is even less studied since it was traditionally pointed as a secondary pathogen (Delatour 1969) related to stressed trees in poor plantations (Capretti 1980).…”

“…C. pinea has been reported in iForest 12: [193][194][195][196][197][198] 195 Italy since several years as the causal agent of necrosis and cankers on stems and branches on P. pinea, P. nigra and P. radiata (Capretti 1978, 1980, Luchi et al 2015. A possible reason for the lack of knowledge on this pathogen is that the identification of Caliciopsis canker symptoms become more challenging as tree size increases (Munck et al 2015(Munck et al , 2016. Moreover, C. pinea symptoms, such as pitching blackened, rough, resinosis and sunken bark, are similar to (and may be confused with) those caused by other important pine pathogens like Fusarium circinatum, Diplodia pinea or Diplodia scrobiculata.…”

“…It infects pine trees of all ages mainly in sandy and well-drained soils in North America (Munck et al 2016). In eastern USA C. pinea may affect Pinus echinata Mill, Pinus pungens Lamb, Pinus rigida Mill, Pinus virginiana Mill, Pinus taeda L. and Pinus strobus L., the white pine, which is suffering a severe damage over the last years (LaFlamme 2004, Munck et al 2015. C. pinea has been observed in Europe on exotic pine species, such as Pinus pumila (Pall.)…”