Active (left) and hypovirulent (right) cankers on European chestnut.	Development of chestnut blight
	Ursula Heiniger (Project leader)

Deutsch

Contents: Rationale Project aims Methods Work plan Publications Further information Participants

Rationale All the chestnut forests south of the Alps are infected with chestnut blight (Cryphonectria parasitica). Canker development ceases with time and the hypovirulent form of the pathogen is spreading. However, the Forest Service is reporting an increase in the occurrence of chestnut blight. Project aims The development of chestnut blight will be observed over time. Disease severity, canker incidence and the development of active and hypovirulent cankers will be monitored. C. parasitica isolates will be characterized and the effect of hypovirulent strains on canker development will be assessed. The influence of site conditions (tree age, exposition, weather conditions etc.) on canker development will be estimated and compared to long-term study sites of the Phytopathology group. Methods The monitoring will be performed on the chestnuts (Castanea sativea) of the LTFER site Novaggio. All the chestnut blight cankers will be mapped and measured. C. parasitica will be isolated from selected cankers and their cultural type (white or orange, corresponding to hypovirulent or virulent forms, respectively; see Fig. 1a) and their vegetative compatibility (v-c; see Fig. 1b and 1c) group will be determined. Measurements and isolations will be repeated annually. Fig. 1a Fig. 1b Fig. 1c Back to contents Work plan The methods were developed at the study sites of Lumino and Gnosca (Bissegger, 1993). 1996-98: Annual measurements of the cankers, isolation and characterization of C. parasitica 1999: 4th annual measurement of the cankers, isolation and characterization of C. parasitica, evaluation of the data, publication. Back to contents Publications Bissegger M. 1993. Populationsstruktur und -dynamik von Cryphonectria parasitica in Schweizer Edelkastanienwäldern (Castanea sativa). Diss. ETH-Z. Nr. 10275. Bissegger M., Rigling D., Heiniger U. 1997. Population structure and disease development of Cryphonectria parasitica in European chestnut forests in the presence of natural hypovirulence. Phytopathology 87: 50-59. (abstract) Conedera M. 1991. La situazione del cancro corticale del castagno (Cryphonectria (Endothia) parasitica (Murr.) Barr.) al Sud delle Alpi (Svizzera meridionale). Schweiz. Z. Forstwes. 142: 283-298. Heiniger U., Bissegger M. 1994. Population structure of Cryphonectria parasitica in Swiss Chestnut stands. In: Proc. Am. Chestnut Symp. Mortgantown, V. W. 1992: 143-147. Heiniger U., Rigling D. 1994. Biological control of chestnut blight in Europe. Ann. Rev. Phytopathology 32: 581-599. Further information Additional projects on chestnut blight: WSL Projekt 3.95.976 Kastanienrindenkrebs in Weggis, Phytosanitäre Massnahmen und Bekämpfung mit Hypovirulenz. WSL-Projekt 3.96.1026: Die Bedeutung der Holzlagerung von Kastanie für die Epidemiologie der virusinduzierten Hypovirulenz beim Kastanienrindenkrebs (Cryphonectria parasitica). WSL-Projekt 3.96.1036: Ausbreitung und Stabilität des Cryphonectria Hypovirus (CHV) bei Cryphonectria parasitica. Participants Ursula Heiniger

Projekt 6.95.944 "Entwicklung des Kastanienrindenkrebses"

Back to contents