{"id":2699,"date":"2017-03-21T23:14:42","date_gmt":"2017-03-22T03:14:42","guid":{"rendered":"http:\/\/132.236.156.160\/cuccap\/?page_id=2699"},"modified":"2024-02-21T17:44:19","modified_gmt":"2024-02-21T22:44:19","slug":"downy-mildew","status":"publish","type":"page","link":"http:\/\/132.236.156.160\/cuccap\/disease-management\/melon\/downy-mildew\/","title":{"rendered":"Downy mildew on melon"},"content":{"rendered":"<h2><em>Pseudoperonospora cubensis<\/em><\/h2>\n<p><span style=\"font-weight: 400\">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 and diagnostics can be more difficult.<\/span><\/p>\n<h2 id=\"diagnostic-resources\">Diagnostic Resources<\/h2>\n<ul>\n<li><a href=\"https:\/\/www.vegetables.cornell.edu\/pest-management\/keys-for-identifying-vegetable-diseases\/cucurbit-key\/melon-disease-key\/\" target=\"_blank\" rel=\"noopener\"><strong>Melon Disease Key<\/strong><\/a> &#8211; Smart and McGrath Labs at Cornell Vegetables<\/li>\n<li><a href=\"https:\/\/myipm.app\/vegetables\/\" target=\"_blank\" rel=\"noopener\"><strong>MyIPM for Vegetables<\/strong><\/a> &#8211; An App developed by the Southeastern Vegetable Extension Workers<\/li>\n<li><strong><a href=\"http:\/\/132.236.156.160\/cuccap\/disease-management\/plant-disease-clinics\/\">Plant Disease Clinics<\/a><\/strong><\/li>\n<\/ul>\n<h3>APS Diagnostic Guide<\/h3>\n<ul>\n<li><strong><a href=\"https:\/\/doi.org\/10.1094\/PHP-12-19-0095-DG\" target=\"_blank\" rel=\"noopener\">Diagnostic Guide for Cucurbit Downy Mildew<\/a><\/strong><br \/>\nby: Andres Salcedo, Mary Hausbeck, Stacey Pigg, and Lina M. Quesada-Ocampo<br \/>\nPlant Health Progress: <a class=\"article__tocHeading\" href=\"https:\/\/apsjournals.apsnet.org\/toc\/php\/21\/3\" target=\"_blank\" rel=\"noopener\">Vol. 21, No. 3<\/a><\/li>\n<\/ul>\n<h3>Plant Disease Management Reports<\/h3>\n<ul>\n<li><strong><a href=\"https:\/\/www.plantmanagementnetwork.org\/pub\/trial\/pdmr\/volume17\/abstracts\/v094.asp\" target=\"_blank\" rel=\"noopener\">Evaluation of fungicides for downy mildew management on cantaloupe, Goldsboro 2022.<\/a><\/strong><\/li>\n<\/ul>\n<h2 id=\"disease-control-information\">Disease Control Information<\/h2>\n<ul>\n<li><a href=\"https:\/\/cvp.cce.cornell.edu\/submission.php?id=465\" target=\"_blank\" rel=\"noopener noreferrer\"><strong>Better Know a Pest: Downy Mildew of Cucurbits<\/strong><\/a> &#8211; Smart Lab at Cornell Vegetables (video)<\/li>\n<li><a href=\"https:\/\/cvp.cce.cornell.edu\/submission.php?id=230&amp;crumb=crops|crops|cucumbers|crop*11\" target=\"_blank\" rel=\"noopener noreferrer\"><strong>Cornell Cucurbit Downy Mildew Management Guidelines<\/strong><\/a> &#8211; Cornell Vegetables (2017)<\/li>\n<li><strong><a href=\"https:\/\/veggies.msu.edu\/downy-mildew-news\/\" target=\"_blank\" rel=\"noopener noreferrer\">Downy Mildew News<\/a><\/strong> &#8211; Hausbeck Plant Pathology Research Lab at Michigan State University<br \/>\n<a href=\"http:\/\/132.236.156.160\/cuccap\/espanol\/monitoreo-y-manejo-del-anublo-lanoso-de-las-cucurbitaceas\/\" target=\"_blank\" rel=\"noopener noreferrer\"><strong>Monitoreo y Manejo del A\u00f1ublo Lanoso de las Cucurbit\u00e1ceas<\/strong><\/a> &#8211;\u00a0Spanish translation<\/li>\n<li><strong><a href=\"https:\/\/blogs.cornell.edu\/livegpath\/gallery\/cucurbits\/downy-mildew-o-cucurbits-early-symptoms\/\" target=\"_blank\" rel=\"noopener noreferrer\">Downy mildew on cucurbits: Early symptoms<\/a><\/strong> &#8211; McGrath Lab at Long Island Research and Extension Center, Cornell University<\/li>\n<li><a href=\"https:\/\/blogs.cornell.edu\/livegpath\/gallery\/cucurbits\/downy-mildew-on-cucurbits-other-symptoms-and-imitators\/\" target=\"_blank\" rel=\"noopener noreferrer\"><strong>Downy mildew on cucurbits: Other symptoms and imitators<\/strong><\/a> &#8211; McGrath Lab at Cornell Vegetables<\/li>\n<li><strong><a href=\"http:\/\/cdm.ipmpipe.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">The Cucurbit Downy Mildew Forecast ipmPIPE<\/a><\/strong> -USDA NIFA (2007 &#8211; 2019)<\/li>\n<li><strong><a href=\"https:\/\/www.vegetables.cornell.edu\/crops\/cucurbits\/downy-mildew\/\" target=\"_blank\" rel=\"noopener\">Resources for commercial growers: Downy Mildew<\/a><\/strong> &#8211;\u00a0Smart Lab at Cornell Vegetables<\/li>\n<li><a href=\"https:\/\/veggiepathology.wordpress.ncsu.edu\/for-growers\/disease-fact-sheets\/\" target=\"_blank\" rel=\"noopener\"><strong>Vegetable Pathology Lab Factsheets<\/strong><\/a> &#8211; Quesada-Ocampo Lab at North Carolina State University<br \/>\n<strong><a href=\"https:\/\/content.ces.ncsu.edu\/cucurbit-downy-mildew\" target=\"_blank\" rel=\"noopener noreferrer\">Cucurbit Downy Mildew<\/a> <\/strong>&#8211; NC State Vegetable Pathology Factsheets<br \/>\n<strong><a href=\"https:\/\/content.ces.ncsu.edu\/cucurbit-downy-mildew\/anublo-lanoso-en-cucurbitaceas\" target=\"_blank\" rel=\"noopener noreferrer\">A\u00f1ublo lanoso en cucurbit\u00e1ceas<\/a> <\/strong>&#8211; NC State Hoja informativa de pat\u00f3genos de vegetales<\/li>\n<\/ul>\n<h2>Images of Downy mildew on Melon<\/h2>\n<div style=\"width: 510px\" class=\"wp-caption alignnone\"><a href=\"http:\/\/www.hort.cornell.edu\/livegpath\/images\/cucurbit-downy-mildew18x500.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img decoding=\"async\" loading=\"lazy\" src=\"http:\/\/www.hort.cornell.edu\/livegpath\/images\/cucurbit-downy-mildew18x500.jpg\" alt=\"disease symptoms on a leaf\" width=\"500\" height=\"375\" \/><\/a><p class=\"wp-caption-text\">Figure 1. Initially spots are light yellow with a dark green border that appears water-soaked. The spots enlarge and become brown (necrotic). They are not angular like symptoms on cucumber and butternut squash. Image provided by Dr. Margaret McGrath, Vegetable Pathology, Cornell University.<\/p><\/div>\n<div style=\"width: 510px\" class=\"wp-caption alignnone\"><a href=\"http:\/\/www.hort.cornell.edu\/livegpath\/images\/cucurbit-downy-mildew5x500.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img decoding=\"async\" loading=\"lazy\" src=\"http:\/\/www.hort.cornell.edu\/livegpath\/images\/cucurbit-downy-mildew5x500.jpg\" alt=\"disease symptoms on leaf\" width=\"500\" height=\"667\" \/><\/a><p class=\"wp-caption-text\">Figure 2. The spots enlarge and become brown (necrotic). They are not angular like symptoms on cucumber and butternut squash. Image provided by Dr. Margaret McGrath, Vegetable Pathology, Cornell University.<\/p><\/div>\n<div style=\"width: 510px\" class=\"wp-caption alignnone\"><a href=\"http:\/\/www.hort.cornell.edu\/livegpath\/images\/cucurbit-downy-mildew4x500.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img decoding=\"async\" loading=\"lazy\" src=\"http:\/\/www.hort.cornell.edu\/livegpath\/images\/cucurbit-downy-mildew4x500.jpg\" alt=\"disease symptoms on leaf\" width=\"500\" height=\"457\" \/><\/a><p class=\"wp-caption-text\">Figure 3. Initially spots are light yellow with a dark green border that appears water-soaked. The spots enlarge and become brown (necrotic). They are not angular like symptoms on cucumber and butternut squash. Image provided by Dr. Margaret McGrath, Vegetable Pathology, Cornell University.<\/p><\/div>\n<div style=\"width: 510px\" class=\"wp-caption alignnone\"><a href=\"http:\/\/www.hort.cornell.edu\/livegpath\/images\/cucurbit-downy-mildew6x500.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img decoding=\"async\" loading=\"lazy\" src=\"http:\/\/www.hort.cornell.edu\/livegpath\/images\/cucurbit-downy-mildew6x500.jpg\" alt=\"disease symptoms on leaf\" width=\"500\" height=\"475\" \/><\/a><p class=\"wp-caption-text\">Figure 4. Upon close examination of some spots on the underside of leaves, it can be seen that major veins in the leaf form a barrier to expansion of downy mildew in this type of cucurbit as in others. Image provided by Dr. Margaret McGrath, Vegetable Pathology, Cornell University.<\/p><\/div>\n<div style=\"width: 510px\" class=\"wp-caption alignnone\"><a href=\"http:\/\/www.hort.cornell.edu\/livegpath\/images\/cucurbit-downy-mildew7x500.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img decoding=\"async\" loading=\"lazy\" src=\"http:\/\/www.hort.cornell.edu\/livegpath\/images\/cucurbit-downy-mildew7x500.jpg\" alt=\"disease symptoms on leaf\" width=\"500\" height=\"375\" \/><\/a><p class=\"wp-caption-text\">Figure 5. Upon close examination of some spots on the underside of leaves, it can be seen that major veins in the leaf form a barrier to expansion of downy mildew in this type of cucurbit as in others. The downy mildew pathogen does not produce many spores on cantaloupe leaves, thus the dark fuzzy (downy) fungal growth that commonly occurs on the underside of spots on cucumber and butternut squash leaves will not develop on these spots. Image provided by Dr. Margaret McGrath, Vegetable Pathology, Cornell University.<\/p><\/div>\n<div style=\"width: 510px\" class=\"wp-caption alignnone\"><a href=\"http:\/\/www.hort.cornell.edu\/livegpath\/images\/cucurbit-downy-mildew8x500.jpg\" target=\"_blank\" rel=\"noopener noreferrer\"><img decoding=\"async\" loading=\"lazy\" src=\"http:\/\/www.hort.cornell.edu\/livegpath\/images\/cucurbit-downy-mildew8x500.jpg\" alt=\"disease symptoms on leaf\" width=\"500\" height=\"375\" \/><\/a><p class=\"wp-caption-text\">Figure 6. Upon close examination of some spots on the underside of leaves, it can be seen that major veins in the leaf form a barrier to expansion of downy mildew in this type of cucurbit as in others (see arrows). The downy mildew pathogen does not produce many spores on cantaloupe leaves, thus the dark fuzzy (downy) fungal growth that commonly occurs on the underside of spots on cucumber and butternut squash leaves will not develop on these spots. Image provided by Dr. Margaret McGrath, Vegetable Pathology, Cornell University.<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Pseudoperonospora cubensis 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 [&hellip;]<\/p>\n","protected":false},"author":8,"featured_media":0,"parent":1272,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"page-fullwidth.php","meta":{"footnotes":""},"tags":[497],"_links":{"self":[{"href":"http:\/\/132.236.156.160\/cuccap\/wp-json\/wp\/v2\/pages\/2699"}],"collection":[{"href":"http:\/\/132.236.156.160\/cuccap\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/132.236.156.160\/cuccap\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/132.236.156.160\/cuccap\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"http:\/\/132.236.156.160\/cuccap\/wp-json\/wp\/v2\/comments?post=2699"}],"version-history":[{"count":24,"href":"http:\/\/132.236.156.160\/cuccap\/wp-json\/wp\/v2\/pages\/2699\/revisions"}],"predecessor-version":[{"id":15715,"href":"http:\/\/132.236.156.160\/cuccap\/wp-json\/wp\/v2\/pages\/2699\/revisions\/15715"}],"up":[{"embeddable":true,"href":"http:\/\/132.236.156.160\/cuccap\/wp-json\/wp\/v2\/pages\/1272"}],"wp:attachment":[{"href":"http:\/\/132.236.156.160\/cuccap\/wp-json\/wp\/v2\/media?parent=2699"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/132.236.156.160\/cuccap\/wp-json\/wp\/v2\/tags?post=2699"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}