ISHS Acta Horticulturae 386: XVI International Symposium on Fruit Tree Virus diseases
ETIOLOGY OF A PEAR DECLINE DISEASE IN ITALY AND SUSCEPTIBILITY OF PEAR VARIETY AND ROOTSTOCK TO PHYTOPLASMA-ASSOCIATED PEAR DECLINE |
| Authors: | L. Giunchedi, C. Poggi Pollini, R. Bissani, A.R. Babini, V. Vicchi |
| Abstract:
A pear tree syndrome characterized mainly by premature leaf reddening and fall is common in orchards of central and northern Italy. It is mainly a problem in young orchards of the cultivars: Comice, Williams, Abate Fetel and Kaiser propagated on quince or seedling rootstocks. Decline symptoms have also been observed in trees of several cultivars growing on their own-rootstocks. Phytoplasmas detected by fluorescence microscopy were strongly associated with the leaf reddening condition. A preliminary survey indicated that Conference trees are only slightly affected, regardless of the type of rootstock, while Comice trees showed more intense leaf symptoms on seedlings of Pyrus communis than on quince rootstocks, and Abate Fetel, Kaiser and Williams trees showed about the same susceptibility on both rootstocks. Own-rooted Comice trees showed the stongest symptoms while there were no symptoms on own-rooted Conference trees even when heavily infected with phytoplasmas. Regarding the rootstocks, trees on P. communis seedlings, quince BA 29 and quince CTS 212 showed about the same symptom intensity which was less severe than that presented by trees on quince A, quince C or the clonal rootstock OHF 333. | |
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