Preliminary Note on Birds as Carriers of the Chestnut Blight Fungus

Heald, F. D.; Studhalter, R. A.

doi:10.1126/science.38.973.278

Cited by 21 publications

(19 citation statements)

References 1 publication

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“…Conidia are mainly splash dispersed by rain over short distances (a few metres), or washed down the stem and branches (Griffin, 1986). However, birds, insects, mites or windborne dust may also transport them over long distances (Heald and Studhalter, 1914;Russin et al, 1984;Wendt et al, 1983). If conidia reach the ground, they may remain viable in the soil for a long time (Heald and Gardner, 1914).…”

Section: Life Cycle and Reproductionmentioning

confidence: 99%

Cryphonectria parasitica, the causal agent of chestnut blight: invasion history, population biology and disease control

Rigling

Prospero

2017

Molecular Plant Pathology

358

295

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Summary Chestnut blight, caused by Cryphonectria parasitica, is a devastating disease infecting American and European chestnut trees. The pathogen is native to East Asia and was spread to other continents via infected chestnut plants. This review summarizes the current state of research on this pathogen with a special emphasis on its interaction with a hyperparasitic mycovirus that acts as a biological control agent of chestnut blight. Taxonomy Cryphonectria parasitica (Murr.) Barr. is a Sordariomycete (ascomycete) fungus in the family Cryphonectriaceae (Order Diaporthales). Closely related species that can also be found on chestnut include Cryphonectria radicalis, Cryphonectria naterciae and Cryphonectria japonica. Host range Major hosts are species in the genus Castanea (Family Fagaceae), particularly the American chestnut (C. dentata), the European chestnut (C. sativa), the Chinese chestnut (C. mollissima) and the Japanese chestnut (C. crenata). Minor incidental hosts include oaks (Quercus spp.), maples (Acer spp.), European hornbeam (Carpinus betulus) and American chinkapin (Castanea pumila). Disease symptoms Cryphonectria parasitica causes perennial necrotic lesions (so‐called cankers) on the bark of stems and branches of susceptible host trees, eventually leading to wilting of the plant part distal to the infection. Chestnut blight cankers are characterized by the presence of mycelial fans and fruiting bodies of the pathogen. Below the canker the tree may react by producing epicormic shoots. Non‐lethal, superficial or callusing cankers on susceptible host trees are usually associated with mycovirus‐induced hypovirulence. Disease control After the introduction of C. parasitica into a new area, eradication efforts by cutting and burning the infected plants/trees have mostly failed. In Europe, the mycovirus Cryphonectria hypovirus 1 (CHV‐1) acts as a successful biological control agent of chestnut blight by causing so‐called hypovirulence. CHV‐1 infects C. parasitica and reduces its parasitic growth and sporulation capacity. Individual cankers can be therapeutically treated with hypovirus‐infected C. parasitica strains. The hypovirus may subsequently spread to untreated cankers and become established in the C. parasitica population. Hypovirulence is present in many chestnut‐growing regions of Europe, either resulting naturally or after biological control treatments. In North America, disease management of chestnut blight is mainly focused on breeding with the goal to backcross the Chinese chestnut's blight resistance into the American chestnut genome.

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Section: Life Cycle and Reproductionmentioning

confidence: 99%

Cryphonectria parasitica, the causal agent of chestnut blight: invasion history, population biology and disease control

Rigling

Prospero

2017

Molecular Plant Pathology

358

295

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“…The conclusion has been reached that birds, and especially migratory birds (6,7), are capable of carrying large numbers of viable pycnospores of the blight fungus for considerable distances; and that insects (9, 10) may be important agents in the local dissemination of the blight. Birds were shown to be carrying pycnospores only; the same was true of nearly all of the insects from which positive results were obtained, although a very small number of ascospores were found on several beetles.…”

Section: Practical Bearing Of the Results On The Dissemination By Birmentioning

confidence: 99%

“…A study of the part taken by birds and insects in the dissemination of the chestnut blight fungus, Endothia parasitica (Murr.) And., has shown that both birds (6,7) and insects (9,10) can carry high numbers of pycnospores of this fungus. There are a number of possible sources from which these pycnospores may have been obtained, but it was thought that by far the greater number of them were brushed from both diseased and healthy chestnut bark during the normal movements of the birds and insects over these surfaces.…”

Section: Introductionmentioning

confidence: 99%

The Persistence of Viable Pycnospores of the Chestnut Blight Fungus on Normal Bark Below Lesions

Studhalter¹,

Heald²

1915

American J of Botany

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“…While C. chrysosperma spores can be wind and rain dispersed, sapsuckers also facilitate spore movement from aspen to willow during trips from nests to feeding sites. Migratory birds are known to carry spores on their feathers and feet (Warner and French 1970), and birds in the eastern United States carried chestnut blight spores in high numbers (Heald and Studhalter 1914).…”

Section: Fungal Infectionmentioning

confidence: 99%

Interactions of sapsuckers andCytosporacanker can facilitate decline of riparian willows

Kaczynski

Cooper

Jacobi

2014

Botany

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Drought has caused large-scale plant mortality in ecosystems around the globe. Most diebacks have affected upland forest species. In the past two decades, a large-scale decline of riparian willows (Salix L.) has occurred in Rocky Mountain National Park, Colorado. We examined whether climatic or biotic factors drive and maintain the willow community decline. We compared annual growth and dieback of willows inside and outside of 14-year-old ungulate exclosures and measured groundwater depth and predawn xylem pressures of stems as indicators of drought stress. We also performed an aerial photo analysis to determine the temporal dynamics of the decline. Aerial photo analysis indicated willow decline occurred between 2001 and 2005 and was best explained by an increase in moose population and a decrease in peak stream flows. A new mechanism for willow stem dieback was identified, initiated by red-naped sapsucker wounding willow bark. Wounds became infected with fungus that girdled the stem. DNA analyses confirmed Valsa sordida (Cytospora chrysosperma) as the lethal fungus. Captured sapsuckers had V. sordida spores on feet and beaks identifying them as one possible vector of spread. Predawn xylem pressure potentials remained high through the growing season on all study willows regardless of depth to ground water. Our results indicate that additional mechanisms may be involved in tall willow decline.Résumé : La sécheresse est une cause de mortalité des végétaux à grande échelle dans les écosystèmes sur toute la planète. La plupart de ces dépérissements terminaux ont affecté les espèces forestières des hautes terres. Au cours des deux dernières décennies, un déclin à grande échelle du saule ripisylve est survenu dans le Rocky Mountain National Park, au Colorado. Les auteurs ont examiné si des facteurs climatiques ou biotiques sont responsables et entretiennent le déclin de la communauté des saules. Ils ont comparé la croissance annuelle et le dépérissement terminal des saules à l'intérieur et à l'extérieur d'exclos d'ongulés de 14 ans, et mesuré la profondeur de la nappe phréatique et les pressions du xylème des tiges avant l'aube, comme indicateurs du stress de la sécheresse. Ils ont aussi procédé à une analyse de photos aériennes afin de déterminer la dynamique temporelle du déclin. L'analyse des photos aériennes a indiqué que le déclin des saules est survenu entre 2001 et 2005, et qu'il s'expliquait vraisemblablement par l'augmentation de la population d'orignaux et par la diminution des pics d'écoulement des eaux. Un nouveau mécanisme expliquant le dépérissement terminal des saules a été identifié, initié par des blessures causées à l'écorce des saules par le pic à nuque rouge. Les blessures étaient infectées par des champignons qui entouraient la tige. Les analyses d'ADN ont confirmé que Valsa sordida (Cytospora chrysosperma) constituait le champignon létal. Les pics à nuque rouge capturés étaient porteurs de spores de V. sordida au niveau des pattes et du bec, permettant ainsi de les identifier comme vecteurs possib...

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Preliminary Note on Birds as Carriers of the Chestnut Blight Fungus

Cited by 21 publications

References 1 publication

Cryphonectria parasitica, the causal agent of chestnut blight: invasion history, population biology and disease control

Cryphonectria parasitica, the causal agent of chestnut blight: invasion history, population biology and disease control

The Persistence of Viable Pycnospores of the Chestnut Blight Fungus on Normal Bark Below Lesions

Interactions of sapsuckers andCytosporacanker can facilitate decline of riparian willows

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