The infected area of leaves turns yellow around the spots resulting in premature leaf fall. The spots may be round or may have asymmetrical or feathery ends. The disease symptoms first appear on older leaves present on lower area of plants, later the symptoms spreads upwards. rosae causes formation of purple to black spots on leaves and shoot of infected rose plants ( Figure 1). Almost all rose varieties are susceptible to black spot disease. This fungal disease is caused by Diplocarpon rosae, and prevails throughout the world. Among different leaf spot diseases, black spot disease of rose holds an important place. Leaf spot diseases caused by various fungi are a common pathological constraint of a number of plant species. Therefore fungal diseases cause a severe reduction in production and subsequently lower economic return to grower. More than 80% plants diseases are caused by nasty fungal pathogenic microbes. It is estimated that world faces nearly 13% losses in agriculture produce because of plant diseases caused by a number of pathogens. Diseases are an important reason for losses in agricultural crop commodities. The management of rose diseases requires frequent use of fungicides that adversely affect the environment and raise costs of production. Rose crop is subjected to a number of insect pest and fungal diseases. Nevertheless, a big gap between demand and supply of flowers and relevant products still exists. The increased utilization of cut flowers in hotels, restaurants and banquet halls business has resulted due to increased living standard of people. In case of Pakistan, area under flowering crops is estimated more than 17000 acres. Roses provide high revenue to farmers and increase employment opportunities. Rose cultivation is increasing in Pakistan because of its ornamental and medicinal values.
Its cultivation is performed in both open fields and protected greenhouses. Various parts of rose plants are being used in different types of medicinal formulations. It is also cultivated because of its medicinal importance.
Rose is an economically important horticulture crop cultivated throughout the world and is generally referred as king of flowers. Pakistan being an agricultural country with diverse agro climatic zones has a huge potential for the cultivation of roses. This trend has built up a pressure on the successful cultivation of healthy rose plants in the developing countries, like Pakistan. This is due to the increasing labour and energy costs in Europe. There is a shifting tendency towards sourcing floricultural products from developing countries like Bangladesh, India and Pakistan. There are over 200 species and more than 18000 cultivars of roses. Rose (Rosa sp.) belongs to family Rosaceae.
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