1,720,985 research outputs found
Biological control of chestnut diseases in Italy: effectiveness of blight and ink disease management
No full textIn Italy, chestnut stands and orchards suffered from blight and ink disease. After severe damage caused by blight, a spontaneous re-growing of chestnut trees has been observed in relation to the natural spread of hypovirulence, which is caused by the hypovirulent isolates of Cryphonectria parasitica, the causal agent of blight. Field investigations on unmanaged chestnut stands and coppices have emphasised a widespread but variable presence of chestnut blight in the plots visited. Limited levels of mortality due to blight have been recorded on the study sites. Observations have highlighted the effectiveness of the natural spread of hypovirulence, with a clear prevalence of healed and healing cankers in almost all the stands surveyed. Inocula produced in healing cankers collected on the study sites were investigated by means of laboratory and field tests. Differing percentages of C. parasitica morphotypes (normal, intermediate, white, and pigmented) were detected. Artificial inoculations using these inocula produced healing cankers, while strains obtained from single conidia isolations produced different infections and cankers. Intermediate strains even without dsRNA produced non-lethal infections. Ink disease has been causing severe damage to Italian chestnut orchards and stands. Although the attacks of Phytophthora cambivora are limited, each year they still cause the death of trees in many areas. The antagonistic activity of Trichoderma viride and T. harzianum was assayed in laboratory tests, and proved of perspectives for biological control. This was achieved by using organic manure in orchards: the treatments were efficient, and suffering trees recovered. The use of natural and biological controls makes it possible to limit the damage caused to chestnut trees by these two main diseases
Diseases effects on sustainability and evolution of chestnut ecosystem in Italy
No full textThe two most destructive diseases of chestnut (Castanea sativa Miller) are chestnut blight and ink diseases which are spreading in Italy and through other European countries. These constrain factors play an important role in the evolution of chestnut stands and orchards, affecting their management. Predominance of hypovirulence was observed in the majority of European chestnut stands and orchards. Healing cankers arising from the action of hypovirulent strains of Cryphonectria parasitica were detected in the stands investigated. Factors involved in the natural spread and predominance of the hypovirulent strains are cited. New lines of the parasite spread, but the damages produced are undetectable for the effect of the natural mixed inoculum, which could buffer any variations in the genome lines. Management of chestnut stands and orchards and the spread of hypovirulent strains enhances the natural biological control of the disease. Ink disease attacks produce severe damage in chestnut stands and orchards and influence their evolution Treatments with integrated organic fertilisers have produced the re-growth of symptomatic chestnut trees
Phytosanitary criteria for the protection of chestnut orchards and stands against chestnut blight and ink disease
No full textLa difesa biologica dei castagneti: stabilità dell'ipovirulenza e prime indagini sugli antagonisti del Mal dell'inchiostro
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Investigation on natural spread of chestnut blight hypovirulence in Italy and other European countries
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