{"id":2086,"date":"2017-02-15T12:33:56","date_gmt":"2017-02-15T17:33:56","guid":{"rendered":"http:\/\/132.236.156.160\/cuccap\/?page_id=2086"},"modified":"2024-02-21T17:39:44","modified_gmt":"2024-02-21T22:39:44","slug":"downy-mildew","status":"publish","type":"page","link":"http:\/\/132.236.156.160\/cuccap\/disease-management\/cucumber\/downy-mildew\/","title":{"rendered":"Downy mildew on cucumber"},"content":{"rendered":"
\"disease<\/a>

Cucurbit Downy Mildew on a leaf. Image provided by Chris Smart, Cornell University.<\/p><\/div>\n

Pseudoperonospora cubensis<\/em><\/h2>\n

Downy mildew causes angular, yellow to brown lesions on top of the leaves that are restricted by leaf veins. When conditions are favorable, for example early in the morning when moisture is higher, lesions observed on the underside of the leaf may be covered in dark \u201cdown\u201d. This downy growth is masses of pathogen spores called sporangia, which can be seen in the field with a 20X hand lens. In the presence of water, sporangia can directly germinate or differentiate into swimming zoospores that infect leaves. Identification of downy mildew in cucumber can generally be done in a field setting due to the characteristic angular lesions and pathogen sporulation in the underside of the leaf. However, in crops such as watermelon and cantaloupe where lesions do not always have the characteristic angular shape, sporulation can be scarce\u00a0and diagnostics can be more difficult.\u00a0<\/span><\/p>\n

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\"cucumber<\/a>

Cucurbit Downy Mildew in a cucumber field. Image provided by Chris Smart, Cornell University.<\/p><\/div>\n

Diagnostic Resources<\/h2>\n