(1987). Chestnut Blight: The Classical Problem of an Introduced Pathogen. Mycologia: Vol. 79, No. 1, pp. 23-37.

http://www.stoppinginvasives.org/dotAsset/cb3cbc30-bdb7-4510-896f-c689a4739c4c.pdf

Chestnut blight: the classical problem of an introduced pathogen

Prospero, S., Conedera, M., Heiniger, U., and Rigling, D. 2006. Saprophytic activity and sporulation of Cryphonectria parasitica on dead chestnut wood in forests with naturally established hypovirulence. Phytopathology 96:1337-1344. Sustainable biological control of the chestnut blight fungus Cryphonectria parasitica with hypovirulence depends on the production and dissemination of hypovirus-infected propagules of the pathogen. We investigated the ability of C. parasitica to sporulate and produce hypovirus-infected spores on recently dead chestnut wood in coppice stands in southern Switzerland where hypovirulence has been naturally established. The number and type (active, inactive, or none) of cankers was assessed on experimentally cut and stacked stems, firewood stacks, and natural dead wood. Hypovirus-free and hypovirus-infected strains readily survived for more than 1 year in the chestnut blight cankers of the stacked stems. Sporulation of C. parasitica was observed on the surface of preexisting inactive and active cankers, as well as on newly colonized bark areas and was significantly more abundant than on comparable cankers on living stems. On all types of dead wood, we observed more stromata with perithecia than with pycnidia; however, a large proportion of the stromata was not differentiated. All perithecia examined yielded only hypovirus-free ascospores. The incidence of pycnidia that produced hypovirus-infected conidia ranged from 5% on natural dead wood to 41% on the experimental stacks. The mean virus transmission rate into conidia was 69%. Our study demonstrates a considerable saprophytic activity of C. parasitica on recently dead chestnut wood and supports the hypothesis of a role of this saprophytic phase in the epidemiology of hypovirulence. Additional keywords: Castanea sativa, Cryphonectria hypovirus, CHV-1, reproductive biology, sexual and asexual reproduction.

https://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO-96-1337

Saprophytic Activity and Sporulation of Cryphonectria parasitica on Dead Chestnut Wood in Forests with Naturally Established Hypovirulence

Chestnut Blight and its Control

Preface 1 The Origins of Urban Forestry J Koch 2 Understanding the Benefits and Costs of Urban Forest Ecosystems DJ Nowak, JF Dwyer 3 Laws and Ordinances VD Merullo, MVD Errico 4 Community Planning and the Natural Environment WF Elmendorf 5 Planning and Design S Strom 6 Tree Inventory and Systematic Management RS Wolowicz, M Gera 7 Urban and Community Forestry Financing and Budgeting RL Tate 8 Community Involvement in Urban Forestry Programs J Nichnadowicz 9 Soils: The Key to Successful Establishment of Urban Vegetation GA Hawver, NL Bassuk 10 Selecting Trees for Community Landscapes H Gerhold, W Porter 11 Guide to Selecting and Specifying Quality Nursery Stock J Sellmer, L Kuhns 12 Planting and Maintenance JW Consolloy 13 Pruning RM Argent 14 Trees, Utilities, and Municipalities RF Lee, RS Wolowicz 15 Tree Roots vs Sidewalks and Sewers WR Comery 16 Hazard Tree Inspection, Evaluation, and Management ET Smiley, et al 17 Integrated Pest Management of Diseases and Insects D Smith-Fiola 18 Tree Appraisal: The Goal is Equity JB Ingram 19 Leaf Composting PF Strom, MS Finstein 20 Urban Tree Removal DF Blair 21 Recycling Urban Tree Removals EA Lempicki, E Cesa 22 a Tree City, USA J Rosenow, M Yager A Case Study of Paramus, New Jersey -- A A Tree City, USA≅Community WR Comery 23 Attracting and Managing for Wildlife KE Clark 24 Managing Urban Ecosystems: A Look to the Future of Urban Forestry LR Neville

Handbook of urban and community forestry in the Northeast.

Publisher Summary The name “chestnut” refers to seven species of deciduous, nut-bearing trees found native and introduced throughout the world. In 1838, a root disease was reported on European chestnut in Portugal, and soon after this “ink disease” was found in several other parts of southern Europe. Ink disease is assumed to have entered the United States in the mid-l800s, and probably accounted for the recession of American chestnut from large areas in the Gulf and Mid-Atlantic states in the United States, and inland to the foothills and mountains of Mississippi, Alabama, Georgia, Tennessee, Maryland, Virginia, and the Carolinas. Chestnut blight, or chestnut bark disease is caused by the fungus Cryphonectria parasitica Barr, formerly called Endothia parasitica And. & And. The fungus enters wounds, grows in and under the bark, and eventually kills the cambium all the way around the twig, branch, or trunk. From 1982 through 1986, the 317 cankers that developed on American chestnut stems in 50 sprout clumps were treated with H strains. European chestnuts (C. sativa) were distributed throughout southern Europe from the Caucasus mountains, and the nuts have become an important food source, both cooked whole and ground into flour. Chestnuts are actually fruits, with shells enclosing cotyledons. Two species of weevils lay eggs in the nuts, and the developing larvae make the nuts unmarketable.

The pathogens and pests of chestnuts.

Slugs (Lchmannia marginata Muller) were observed moving and feeding on chestnut blight cankers in woods. Preliminary laboratory tests support the hypothesis that slugs are important vectors in the natural spreading of the blight, complementary to other physical and biological factors.

G. Chelazzi

Papers

Possible role of slugs as vectors of the chestnut blight fungus