7/31/2023 0 Comments Mosaic virus![]() Foliar and flower symptom intensity varies with species and cultivar: symptoms are most severe in summer squash, some pumpkins, and many melons and less severe in cucumber, winter squash, and watermelon. Flowers develop abnormalities and have greenish petals. When the virus becomes systemic, leaves prominently curl downward, develop a mosaic pattern, and remain small. ![]() Symptoms of CMV in cucurbits generally manifest as severe stunting, prominent yellow foliar mosaic, plant and leaf malformation, and stunting due to drastic reduction of leaf size and stem internodes. Plants that are infected with CMV when they are young may develop elongated brown to translucent sunken spots on their petioles. ![]() Symptoms are often transient, becoming more and less obvious as the season and weather progress. Leaves may develop vein-clearing and mosaic, and interveinal areas may become dark green and thick, making leaves look crinkled. The most easily identified symptom of CMV in celery is a downward curling of young petioles, which gives plants and opened or flattened look. Symptoms of CMV vary with viral strain, crop host and genotype, crop maturity stage, and environmental conditions. Many woody and non-woody ornamentals are also hosts. Vegetable hosts include carrot, celery, cucurbits, legumes, lettuce, onion, pepper, spinach, tomato, and rarely potato. It has a host range of more than 1,200 species, and is transmitted by many species of aphids, as well as cucumber beetles. The virus is distributed worldwide but is particularly prevalent in temperate regions. Despite the uncertainty concerning the potential impact on bean and soybean crops in the EU, CPMV satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.Cucumber Mosaic Virus (CMV) can cause severe losses in vegetables, legumes, and ornamentals. There is high uncertainty on the potential impact that CPMV would cause on other natural hosts cultivated in the EU due to the lack of information from the areas of CPMV's current distribution. Should the pest establish in the EU, an impact is expected on cowpea crops at local scale. The cultivated area and production of cowpea in the EU territory are mainly limited to local varieties cultivated at a small scale in Mediterranean EU Member States. Seeds for sowing of cowpea are identified as the major entry pathway. CPMV is also transmitted by several beetle species, one of which, Diabrotica virgifera virgifera, is present in the EU. There is uncertainty on seed transmission by other Fabaceae host species due to lack of information. CPMV is transmitted by cowpea seeds, with uncertainty on the transmission rate. The virus has been reported sporadically on some other cultivated species of the family Fabaceae, including soybean and some common bean varieties. CPMV is considered a major pathogen of cowpea on which it causes symptoms ranging from mild to severe mosaic, chlorosis and necrosis. ![]() It has been reported from the Americas, and several countries in Africa and Asia and it is not known to be present in the EU in natural conditions. The pathogen is not included in the Commission Implementing Regulation (EU) 2019/2072. The identity of CPMV, a member of the genus Comovirus (family Secoviridae), is established and detection and identification methods are available. The EFSA Panel on Plant Health conducted a pest categorisation of cowpea mosaic virus (CPMV) for the EU territory. Competent organisations in Member States. ![]()
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