Abstract

LAF, Jorge G  and  LINARDELLI, Clara E. Detection of Xanthomonas cucurbitae (Bryan) Vauterin et al. affecting fruits of winter squash in Mendoza and San Juan, Argentina. Rev. Fac. Cienc. Agrar., Univ. Nac. Cuyo [online]. 2011, vol.43, n.2, pp.245-253. ISSN 1853-8665.

During 2007/08 and 2008/09, in horticultural commercial farms in Mendoza and San Juan, numerous lesions on winter squash (Cucurbita moschata Duch) fruits surface were observed. They appeared as water-soaked, circular spots of about 3 to 6 mm in diameter, slightly depressed towards the center, where they presented a gummy amber exudate. Towards the interior of the tissues, when superficial lesions joined together, a gelatinous type of rot developed, which deepened to the seed cavity. As a final result, a dry and crusty type of rot covered the fruit, which caused it to be unmarketable. Symptoms of the disease were also observed on leaves, as chlorotic and angular spots of 2 to 3 mm, which could coalesce. The aim of this work was to determine the etiology of the disease. Samples of affected leaves and fruits were taken during both growing seasons, in order to isolate and study the causal agent. Morphobiochemical and pathogenic tests probed that the symptoms were caused by the bacteria Xanthomonas cucurbitae (Bryan) Vauterin et al. This is the first time the pathogen is cited affecting fruits in Argentina.

Keywords : Winter squash; Cucurbita moschata; Fruits; Bacterial disease; Xanthomonas.

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