{"id":12032,"date":"2020-01-16T12:00:26","date_gmt":"2020-01-16T17:00:26","guid":{"rendered":"http:\/\/www.whatgrowsthere.com\/grow\/?p=12032"},"modified":"2019-08-16T10:29:23","modified_gmt":"2019-08-16T14:29:23","slug":"plant-disease-warning-phytophthora-ramorum","status":"publish","type":"post","link":"https:\/\/whatgrowsthere.com\/grow\/2020\/01\/16\/plant-disease-warning-phytophthora-ramorum\/","title":{"rendered":"Plant Disease Warning: Phytophthora ramorum"},"content":{"rendered":"\n<figure class=\"wp-block-image\"><img decoding=\"async\" loading=\"lazy\" width=\"1024\" height=\"768\" src=\"https:\/\/whatgrowsthere.com\/grow\/wp-content\/uploads\/2019\/08\/Rhododendron-phytophthora-foliar-blight-Sept-2013-4-1024x768.jpg\" alt=\"\" class=\"wp-image-12052\" srcset=\"https:\/\/whatgrowsthere.com\/grow\/wp-content\/uploads\/2019\/08\/Rhododendron-phytophthora-foliar-blight-Sept-2013-4-1024x768.jpg 1024w, https:\/\/whatgrowsthere.com\/grow\/wp-content\/uploads\/2019\/08\/Rhododendron-phytophthora-foliar-blight-Sept-2013-4-300x225.jpg 300w, https:\/\/whatgrowsthere.com\/grow\/wp-content\/uploads\/2019\/08\/Rhododendron-phytophthora-foliar-blight-Sept-2013-4-768x576.jpg 768w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><figcaption>Rhododendron infected with <br><em>Phytophthora ramorum<\/em> (Pr) (photo by Dr. Alan S. Windham)<\/figcaption><\/figure>\n\n\n\n<p>Known as \u201csudden oak death\u201d, this serious plant disease (<em>Phytophthora ramorum<\/em>) (Pr) from the West Coast kills oak and other species of trees. It has caused devastating effects on the oak populations in California, Oregon, and Washington, and is also present in Europe. Symptoms include bleeding cankers on the tree&#8217;s trunk and dieback of foliage.<\/p>\n\n\n\n<p>Pr causes foliar blight\/leaf spots\u00a0over 80 susceptible landscape plants including: maple (<em>Acer)<\/em>, <em>Camellia<\/em>, witchhazels (<em>Hamamelis)<\/em>, mountain laurels (<em>Kalmia)<\/em>, honeysuckle (<em>Lonicera),<\/em> magnolias (<em>Magnolia), <\/em>Japanese andromeda (<em>Pieris),<\/em> Douglas fir (<em>Pseudotsuga), <\/em>azaleas and rhododendrons <em>(Rhododendron)<\/em>, lilac (<em>Syringa), <\/em>and<em> <\/em>viburnums<em> (Viburnum).<\/em><\/p>\n\n\n\n<p>All nursery plants from the West Coast are strictly inspected by the USDA for Pr. However, mistakes do happen. In the spring 2019 rhododendrons infected with Pr were shipped to some stores in Tennessee. Fortunately, the plants were quarantined and quickly destroyed.<\/p>\n\n\n\n<p>Pr is a water mold <em>fungus<\/em> disease known as ramorum leaf blight, ramorum dieback, and sudden oak death (SOD).\u00a0In certain areas of California and Oregon, Pr causes bark cankers on several oak (<em>Quercus<\/em>) and tan oak (<em>Lithocarpus densiflorus<\/em>). The bark cankers are fatal to oak and tan oak if the lesions girdle the trunk. Otherwise, trees that develop foliar blights and leaf spots do not die, but may serve as &#8220;reservoir&#8221; hosts for the pathogen.<\/p>\n\n\n\n<p>Pr produces &#8220;bleeding&#8221; cankers on the trunks and branches.\u00a0 The formation of droplets of dark reddish brown liquid on the bark is not usually associated with bark cracks or insect holes.\u00a0 If the outer bark is scraped away, black zone lines surround dead areas in the inner bark.\u00a0 Once a bark canker girdles a branch or stem, the portion of the plant beyond that point dies.\u00a0 Tree death may occur within several months to several years after initial infection.\u00a0 Infected trees are attractive to opportunistic ambrosia and bark beetles, as well as secondary colonization by the sapwood decay fungus (<em>Hypoxylon<\/em>).<\/p>\n\n\n\n<p>West\ncoast nurseries are forbidden to ship susceptible host plants. All plants must\npass inspection \u201cfree of <em>Pr\u201d can be shipped to other states. N<\/em>o chemical control measures\nare currently available.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Known as \u201csudden oak death\u201d, this serious plant disease (Phytophthora ramorum) (Pr) from the West Coast kills oak and other species of trees. It has caused devastating effects on the oak populations in California, Oregon, and Washington, and is also present in Europe. Symptoms include bleeding cankers on the tree&#8217;s trunk and dieback of foliage. [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[11,1397,650,1208,5,991,1154,853,949,1460,616,738,627,1084,1518,998,843,729,712,1031,630,7,935,848],"tags":[],"_links":{"self":[{"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/posts\/12032"}],"collection":[{"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/comments?post=12032"}],"version-history":[{"count":5,"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/posts\/12032\/revisions"}],"predecessor-version":[{"id":12060,"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/posts\/12032\/revisions\/12060"}],"wp:attachment":[{"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/media?parent=12032"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/categories?post=12032"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/whatgrowsthere.com\/grow\/wp-json\/wp\/v2\/tags?post=12032"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}