Beech bark disease occurs when beech trees, predisposed by infestation of the beech scale Cryptococcusfagisuga (Lindinger) (C. fagi (Baer.)), are infected by species of the fungal genus Nectria. Infestation patterns of C. fagisuga on individual trees and in forest stands were studied. Fagussylvatica L. was infested artificially with C. fagisuga. After 3 years, secondary colonization on individual trees was generally restricted to within 1 m from points of introduction. Cryptococcusfagisuga was associated positively with the bark lichen Lecanoraconizaeoides Nye ex Cromb. and negatively with the bark fungus Ascodichaenarugosa Butin. In a young plantation, patterns of scale infestation were related to distance from a large old relic tree and to wind-direction records for the insect's dispersal period. In another plantation the infestation patterns were associated with site topography. In North America, the pattern of continuous spread of C. fagisuga (and of associated disease development) since its introduction in 1890 strongly supports the sequential nature of the causal agent complex proposed by Ehrlich and suggests that susceptibility of F. grandifolia Ehrh. to infestation is so high, at least in the first encounter, that environmental factors which might influence this susceptibility are unimportant in the disease complex.

Sensibilite des jeunes rameaux de Peuplier au M. brunnea 199 Pustules tend to be crowded at the ba.ses of ttie shoots and they seem to be independent of late infection on foliage. Ttiis suggests that shoots have a characteristic pattern in the development of .susceptibility during development. ZusammenfassungDie Anfdlligkcit junger Pappeltriebe gegen Marssonina brunnea (Ell. et Ev.) P. magn. Registriert wurde die Anzahl von Marssonina brunnea-Pusteln an Trieben versehiedener Pappelklone. Eine diesbeziigliche Rangfolge unter den Klonen scheint sowohl zeitlich wie raumlich zu bestehen. Die Methode durfte eine grobe Absehatzung der Anfiilligkeit von Klonen zulassen, es kommen allerdings Unterschiede zwischen Klonen mit gleieher Intensitat des Btattbefalts vor. An der Triebbasis treten die Pusteln nieist gehiiuft auf; mit Spatinfektionen der Blatter scheinen sie nicht zusammenzuhangen. Das la(5t vermuten, da(! Triebe spezifische Auspragungen in der Anfiilligkeit wahrend ihrer Entwicklung durchlaufen. Bibliographie CASTELLANI, E., 1966: Influence des facteurs climatiques sur les infections des Peupliers euramericains par Marssonina brunnea (Ell. et Ev.) P. Magn. Phytopath. mediterr. 5, 41-52. CASTELLANI, E.; CELLERINO, G. P., 1964: Una pericolosa nialattia dei pioppi euroamericani determinata da Marssonina brunnea (Ell. et Ev.) P. Magn. Cellulosa e Carta 15, 8, 3-17. --1969: Cinque anni di osservazioni sul eomportamento di vari ctoni di pioppo verso la Marssonina brunnea. Cellulosa e Carta 10, 4, 3-16. CELLERINO, G. P.; ANSELMI, N.; PINON, J., 1978: Influence de l'age des feuilles de Peuplier sur la sensibilite a Marssonina brunnea. Eur. J. For. Path., 8, 273-279. PINON, J., 1974: Influence de la concentration de l'inoculum sur la sensibilite des peupliers cultives a Marssonina brunnea (Ell. et Ev.) P. Magn. Eur. J. For. Path. 4, 54-59. PINON, J.; POISSONNIER, M., 1975: Etude epidemiologique du Marssonina brunnea (Ell. et Ev.) P. Magn. Eur. J. For. Path. 5, 97-111.

No abstract

No abstract

A sequential sampling scheme is in operation to test the viability and wood decaying ability of commercially produced sachets of Peniophora giganitea suspension in the treatment of pine stumps against Heterobasidion annosum.

Nectria ascospores discharged from a Beech bark diseased tree were monitored by a spore trap, and prevailing meteorological'conditions were recorded. Forest and glasshouse experiments are described in which necrosis of beech bark followed wound inoculation with Nectria isolates during dormancy. Perithecia were produced in vitro and spore dimensions were measured. Linear growth rate of the fungus in culture was compared over a range of temperatures. AbstractAureohasidium pullulans was isolated from Alnus ruhra + Lactarius ohscuratus mycorrhizae in 50 "/o of cases. Antibiotic effects against the fine root pathogen, Fusarium oxysporum, were found.

No abstract

No abstract