{"id":1871,"date":"2017-02-01T13:25:26","date_gmt":"2017-02-01T18:25:26","guid":{"rendered":"http:\/\/132.236.156.160\/cuccap\/?page_id=1871"},"modified":"2024-02-21T17:57:06","modified_gmt":"2024-02-21T22:57:06","slug":"downy-mildew","status":"publish","type":"page","link":"http:\/\/132.236.156.160\/cuccap\/disease-management\/squash\/downy-mildew\/","title":{"rendered":"Downy mildew on Squash and Pumpkin"},"content":{"rendered":"<h2><i>Pseudoperonospora cubensis<\/i><\/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><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<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<h3>Plant Disease Management Reports<\/h3>\n<ul>\n<li><strong><a href=\"https:\/\/veggiepathology.wordpress.ncsu.edu\/files\/2022\/09\/V181.pdf\" target=\"_blank\" rel=\"noopener\">Evaluation of fungicides for management of winter squash downy mildew, Kinston 2021.<\/a><\/strong><\/li>\n<li><strong><a href=\"https:\/\/www.plantmanagementnetwork.org\/pub\/trial\/pdmr\/reports\/2021\/V167.pdf\" target=\"_blank\" rel=\"noopener\">Evaluation of fungicides for control of downy mildew of winter squash, Kinston 2020.<\/a><\/strong><\/li>\n<li><strong><a href=\"https:\/\/veggiepathology.wordpress.ncsu.edu\/files\/2019\/08\/V124.pdf\" target=\"_blank\" rel=\"noopener noreferrer\">Evaluation of cultivars for control of downy mildew on squash, Kinston 2018<\/a>.<\/strong><\/li>\n<li><strong><a href=\"https:\/\/veggiepathology.wordpress.ncsu.edu\/files\/2018\/08\/V148.pdf\" target=\"_blank\" rel=\"noopener noreferrer\">Evaluation of fungicides for control of downy mildew of winter squash, Kinston 2017<\/a>.<\/strong><\/li>\n<li><strong><a href=\"https:\/\/veggiepathology.wordpress.ncsu.edu\/files\/2018\/08\/V151.pdf\" target=\"_blank\" rel=\"noopener noreferrer\">Evaluation of cultivars for control of downy mildew on squash, Kinston 2017.<\/a><\/strong><\/li>\n<\/ul>\n<h2>Images of Downy mildew on Pumpkin (<em>Cucurbita maxima)<\/em><\/h2>\n<div style=\"width: 1210px\" class=\"wp-caption alignnone\"><a href=\"https:\/\/blogs.cornell.edu\/livegpath\/files\/2021\/02\/cucurbit-downy-mildew9x1200.jpg\"><img decoding=\"async\" loading=\"lazy\" src=\"https:\/\/blogs.cornell.edu\/livegpath\/files\/2021\/02\/cucurbit-downy-mildew9x1200.jpg\" alt=\"disease symptoms on leaf\" width=\"1200\" height=\"900\" \/><\/a><p class=\"wp-caption-text\">Downy mildew causes tiny orange-yellow spots on giant pumpkin. Image by Margaret McGrath, Long Island Horticultural Research &amp; Extension Center<\/p><\/div>\n<div style=\"width: 1210px\" class=\"wp-caption alignnone\"><a href=\"https:\/\/blogs.cornell.edu\/livegpath\/files\/2021\/02\/cucurbit-downy-mildew10x1200.jpg\"><img decoding=\"async\" loading=\"lazy\" class=\"size-full\" src=\"https:\/\/blogs.cornell.edu\/livegpath\/files\/2021\/02\/cucurbit-downy-mildew10x1200.jpg\" alt=\"disease symptoms on leaf\" width=\"1200\" height=\"900\" \/><\/a><p class=\"wp-caption-text\">Downy mildew causes tiny orange-yellow spots on giant pumpkin. Leaves often need to be examined closely to see these symptoms.Image by Margaret McGrath, Long Island Horticultural Research &amp; Extension Center<\/p><\/div>\n<div style=\"width: 1210px\" class=\"wp-caption alignnone\"><img decoding=\"async\" loading=\"lazy\" class=\"size-full\" src=\"https:\/\/blogs.cornell.edu\/livegpath\/files\/2021\/02\/cucurbit-downy-mildew11x1200.jpg\" alt=\"pumpkin plants\" width=\"1200\" height=\"900\" \/><p class=\"wp-caption-text\">Downy mildew symptoms are present on some leaves in the field shot above; the image needs to be enlarged greatly to see them. The downy mildew pathogen produces few spores on giant pumpkin 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. Many spots may need to be examined with a microscope to find spores. Downy mildew is not as destructive on giant pumpkin as on other cucurbit crop types; affected leaves are not killed as rapidly. Images by Margaret McGrath, Long Island Horticultural Research &amp; Extension Center<\/p><\/div>\n<h2>Images of Downy mildew on Halloween Pumpkin (<em>Cucurbita pepo<\/em>)<\/h2>\n<div style=\"width: 1210px\" class=\"wp-caption alignnone\"><img decoding=\"async\" loading=\"lazy\" class=\"size-full\" src=\"https:\/\/blogs.cornell.edu\/livegpath\/files\/2021\/02\/cucurbit-downy-mildew21x1200.jpg\" alt=\"disease symptoms on leaf\" width=\"1200\" height=\"900\" \/><p class=\"wp-caption-text\">Small,faint, light yellow, angular spots on <em>Cucurbita pepo<\/em>.<\/p><\/div>\n<div style=\"width: 1210px\" class=\"wp-caption alignnone\"><img decoding=\"async\" loading=\"lazy\" class=\"size-full\" src=\"https:\/\/blogs.cornell.edu\/livegpath\/files\/2021\/02\/cucurbit-downy-mildew23x1200.jpg\" alt=\"disease symptoms on leaf\" width=\"1200\" height=\"900\" \/><p class=\"wp-caption-text\">Small, orange-yellow, angular spots.<\/p><\/div>\n<h2 style=\"text-align: left\">Symptoms of Downy mildew on Butternut Squash<\/h2>\n<div style=\"width: 1210px\" class=\"wp-caption alignnone\"><a href=\"https:\/\/cpb-us-e1.wpmucdn.com\/blogs.cornell.edu\/dist\/8\/5755\/files\/2021\/02\/cucurbit-downy-mildew12x1200.jpg\"><img decoding=\"async\" loading=\"lazy\" class=\"size-full\" src=\"https:\/\/cpb-us-e1.wpmucdn.com\/blogs.cornell.edu\/dist\/8\/5755\/files\/2021\/02\/cucurbit-downy-mildew12x1200.jpg\" alt=\"disease symptoms on leaves\" width=\"1200\" height=\"900\" \/><\/a><p class=\"wp-caption-text\">Symptoms begin as tiny spots with a yellow border. Spots can occur in clusters. Very early symptoms tend to lack the angular appearance common for older symptoms. Image by Margaret McGrath, Long Island Horticultural Research &amp; Extension Center.<\/p><\/div>\n<div style=\"width: 1210px\" class=\"wp-caption alignnone\"><img decoding=\"async\" loading=\"lazy\" class=\"size-full\" src=\"https:\/\/cpb-us-e1.wpmucdn.com\/blogs.cornell.edu\/dist\/8\/5755\/files\/2021\/02\/cucurbit-downy-mildew13x1200.jpg\" alt=\"disease symptoms on leaf\" width=\"1200\" height=\"788\" \/><p class=\"wp-caption-text\">Individual yellow spots on the left side of this image tend to lack the angular appearance common for older symptoms. The spots in the cluster on the right side of this image are exhibiting some angular edges where their expansion was stopped by major veins in the leaf. Image by Margaret McGrath, Long Island Horticultural Research &amp; Extension Center.<\/p><\/div>\n<hr \/>\n<div style=\"width: 1210px\" class=\"wp-caption alignnone\"><img decoding=\"async\" loading=\"lazy\" class=\"size-full\" src=\"https:\/\/blogs.cornell.edu\/livegpath\/files\/2021\/02\/cucurbit-downy-mildew15x1200.jpg\" alt=\"disease symptoms on leaf\" width=\"1200\" height=\"900\" \/><p class=\"wp-caption-text\">Symptoms of Downy mildew on a butternut squash leaf.\u00a0 Image by Margaret McGrath, Long Island Horticultural Research &amp; Extension Center.<\/p><\/div>\n<div style=\"width: 638px\" class=\"wp-caption alignnone\"><img decoding=\"async\" loading=\"lazy\" class=\"size-full\" src=\"https:\/\/blogs.cornell.edu\/livegpath\/files\/2021\/02\/cucurbit-downy-mildew16x1200.jpg\" alt=\"disease symptoms on leaf\" width=\"628\" height=\"628\" \/><p class=\"wp-caption-text\">Close up of the leaf in the previous image; it shows the upper surface of the part of the leaf with the same symptoms. Image by Margaret McGrath, Long Island Horticultural Research &amp; Extension Center.<\/p><\/div>\n<div style=\"width: 870px\" class=\"wp-caption alignnone\"><img decoding=\"async\" loading=\"lazy\" class=\"size-full\" src=\"https:\/\/blogs.cornell.edu\/livegpath\/files\/2021\/02\/cucurbit-downy-mildew17x1200.jpg\" alt=\"disease symptoms on leaf\" width=\"860\" height=\"860\" \/><p class=\"wp-caption-text\">Close up of the leaf in the previous image; it shows the lower surface of the part of the leaf with the same symptoms. Image by Margaret McGrath, Long Island Horticultural Research &amp; Extension Center.<\/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":1274,"menu_order":1,"comment_status":"closed","ping_status":"closed","template":"page-fullwidth.php","meta":{"footnotes":""},"tags":[399,497,554],"_links":{"self":[{"href":"http:\/\/132.236.156.160\/cuccap\/wp-json\/wp\/v2\/pages\/1871"}],"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=1871"}],"version-history":[{"count":51,"href":"http:\/\/132.236.156.160\/cuccap\/wp-json\/wp\/v2\/pages\/1871\/revisions"}],"predecessor-version":[{"id":15722,"href":"http:\/\/132.236.156.160\/cuccap\/wp-json\/wp\/v2\/pages\/1871\/revisions\/15722"}],"up":[{"embeddable":true,"href":"http:\/\/132.236.156.160\/cuccap\/wp-json\/wp\/v2\/pages\/1274"}],"wp:attachment":[{"href":"http:\/\/132.236.156.160\/cuccap\/wp-json\/wp\/v2\/media?parent=1871"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/132.236.156.160\/cuccap\/wp-json\/wp\/v2\/tags?post=1871"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}