1,721,007 research outputs found
First Report of Phytophthora acerina, P. Plurivora, and P. Pseudocryptogea Associated with Declining Common Alder Trees in Italy
Full text linkAttività antagonistica di Trichoderma endofiti nei confronti di Botryosphariaeae associate al deperimento della quercia da sughero
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Epidemiological aspects of Biscogniauxia mediterranea in declining cork oak forests in Sardinia (Italy).
No full textBiscogniauxia mediterranea is one of the most important fungal pathogens involved in oak
decline in the Mediterranean countries. In Sardinia, it has been found as endophyte in several tree and
bush species of the Mediterranean maquis, and in particular on Quercus suber. This work reports the
results of studies made in a declining cork oak forest in North Sardinia in order to establish the most
favourable period and the optimal climatic conditions for the endophytic infections of
B. mediterranea. This fungus is capable of infecting all of the plant organs throughout the whole year,
although its highest frequencies were found in wetter winter periods. On the contrary, in spring and
summer, when rainfall was limited or absent, the frequency was lower, even though the higher
temperatures should have encouraged its growth. Indeed, the results of in vitro tests have shown that
B. mediterranea is a mesophilic fungus, with marked eurythermal properties. It can grow even at
temperatures near to 40°C and its ascospores can germinate at over 35°C
Incidenza del deperimento della quercia da sughero nell’altopiano della Giara (Sardegna)
No full textFirst report of Phytophthora acerina and Phytophthora palmivora causing root rot, bleeding cankers and dieback of English walnut in Italy
Full text linkCourse of the decline incidence during 2002-2004 period in declining cork-oak stands in Sardinia
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Botryosphaeriaceae Species Associated with Stem Canker, Shoot Blight and Dieback of Fraxinus ornus in Italy
Full text linkA severe dieback of flowering ash (Fraxinus ornus L.) has been observed in north-central Italy in the last decades. Symptoms include typical sunken, light-brown cankers on the stem and branches; vascular discoloration; tip and shoot dieback; and foliage necroses. The disease was more evident at the beginning of the growing season, and more severe on young regeneration. Six Botryosphaeriaceae species were consistently isolated from symptomatic plant tissues: Botryosphaeria dothidea, Diplodia fraxini, Diplodia subglobosa, Dothiorella iberica, Dothiorella omnivora and Neofusicoccum parvum. B. dothidea and D. fraxini expressed higher aggressiveness and showed a widespread incidence, being the species most frequently associated with cankers; the other four species were less virulent and more erratic, occurring mainly on succulent branch tips and foliage. Isolates were characterized using morphological and molecular approaches (colony/conidial phenotyping and rDNA-ITS genotyping). Phylogenetic analysis provided congruent phylogenies depicting the relationships of the six taxa with the most closely related conspecifics. Pathogenicity tests on 2-year-old seedlings confirmed the higher virulence of B. dothidea and D. fraxini. Extensive, multi-year field surveys at different sites supported the hypothesis that climatic vagaries, mainly heat, water and drought stresses, impaired tree health and vigor, facilitating infection and pervasive colonization by these Botryosphaeriaceae species. Environmental stressors are thus the key factor bringing the six fungal pathogens together in a multitrophic interaction with F. ornus in a novel, lethal fashion
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