Penetration and infection of western larch seedlings by Botrytis cinerea

Abstract

1989. Penetration and infection of western larch seedlings by Botrytis cinerea. Can. J . Bot. 67: 2596 -2599.The fungus Botrytis cinerea Persoon (ex Fries) is an important pathogen of container-grown conifer seedlings. The examination of whole mounts and serial sections of diseased needles of western larch (Larix occidentalis Nuttall) seedlings with a light microscope confirmed that the development of fungal infection structures conforms to that observed in nonconiferous hosts. Both stomata1 and cuticular penetrations were evident. Infection hyphae displayed occasional taxis toward stomata on senescent needles but not on healthy needles. The treatment of seedlings with fungicides at levels corresponding to 1 and 10% normal application rates induced no consistent changes in fungal structures. DUGAN, F., et BLAKE, G. M. 1989. Penetration and infection of western larch seedlings by Botrytis cinerea. Can. J. Bot. 67 : 2596-2599.Le Botrytis cinerea Persoon (ex Fries) constitue une importante espkce fongique pathogkne pour les plants de conifire produits en recipients. L'examen en microscopie photonique de montages entiers et de sections serikes d'aiguilles prklevkes sur des plants de Larix occidentalis (Nuttall) confirme que le developpement des structures d'infection fongique se comporte de la m&me f a~o n que chez les espkces non coniferiennes observkes. On y retrouve la penetration par les stomates aussi bien qu'i travers la cuticule. Occasionnellement, l'hyphe d'infection montre un certain tactisme vers les stomates chez les feuilles sknescentes mais non quand elles sont bien vivantes. Le traitement des plantules avec des applications de fongicides i des concentrations de 1 et 10% des taux normaux d'application ne changent pas de f a~o n constante les structures fongiques.[Traduit par la revue]

Susceptibility of Norway spruce seedlings to grey mould in the greenhouse during the first growing season

“…In the current study the first symptoms were found on the seedlings on the first and second day after inoculation. Dugan & Blake (1989) reported penetration in larch seedlings within 24 Á/48 h, but the visible symptoms usually appeared within 72 h (more rapidly in senescent needles).…”

“…in Larix occidentalis Nutt.) (Dugan & Blake 1989), and also through wounds and dead tissue (Verhoeff 1980). Stress factors (e.g.…”

Effect of thawing duration and temperature on field performance of frozen-stored Norway spruce container seedlings

“…On the other hand, the mould observed in seedlings thawed for 16 days at 12 °C may be of greater concern during long thawing periods. Low light intensity, moderate temperature and high air relative humidity prevailing in seedling boxes during the thaw are all factors that have been reported to favour the growth of mould (Peterson et al 1988, Dugan and Blake 1989, Peterson and Sutherland 1990. This emphasizes the importance of adequate ventilation in seedling boxes during extended thawing periods.…”

Factors affecting the development of Botrytis cinerea (grey mould) on linseed (Linum usitatissimum) buds, flowers and capsules

“…Other hosts which are particularly susceptible to B. cinerea infection during flowering include pear (Sommer et al, 1985), sunflower , red raspberry (McNicol et al, 1985) and strawberry (Xu et al, 2000). Senescent needles of larch seedlings were more susceptible to B. cinerea than green needles (Dugan & Blake, 1989) and senescence increases susceptibility of many hosts, since B. cinerea is not a strong pathogen on undamaged living tissues (Van den Heuvel, 1987). Infections occurring at these two susceptible stages account for high proportions of the yield losses associated with grey mould on linseed (Mercer et al, 1994).…”