{"id":2365,"date":"2023-06-14T04:33:00","date_gmt":"2023-06-14T08:33:00","guid":{"rendered":"http:\/\/www.blog.sdps-bbs.com\/?p=2365"},"modified":"2025-09-17T13:16:08","modified_gmt":"2025-09-17T17:16:08","slug":"question-what-is-causing-maple-trees-to-have-black-spots","status":"publish","type":"post","link":"https:\/\/www.purdue.edu\/fnr\/extension\/question-what-is-causing-maple-trees-to-have-black-spots\/","title":{"rendered":"Question: What Is Causing Maple Trees To Have Black Spots?"},"content":{"rendered":"
\n

\"MapleQuestion:<\/em> we have several maple trees in our neighborhood afflicted with this black spot (see attached photo). What can we do to protect our maple trees?<\/p>\n

Anwer:<\/em> while it is difficult to confirm a diagnosis from photos alone it looks and could be a fungal disease called tar spot. The most common species are Rhytisma acerinum and R. punctatum<\/em>. Symptoms first appear in late spring or early summer as infected leaves develop light green or yellow-green spots. During mid to late summer these produce black tar-like raised structures on the upper surface of leaves within the yellow spots. R. acerinum<\/em> causes larger spots that are 0.5 to 2 cm in diameter; R.punctatum<\/em> causes many small punctate spots that are smaller (about 1mm in diameter). Spots caused by R. punctatum<\/em> are sometimes called speckled tar spots.<\/p>\n

Tar spot is a common disease on silver maple and is primarily considered to be a cosmetic problem rather than a serious threat. The Purdue Plant and Pest Diagnostic Laboratory has additional information on tar spot including more photos and best treatment, Tar Spot on Maple<\/a>.<\/p>\n

To confirm a diagnosis, you can submit a sample directly to the Purdue Plant & Pest Diagnostic Lab<\/a> (PPDL) or find a certified arborist<\/a> to come to your property and access your tree.<\/p>\n

Resources:<\/strong>
\nLarge Spots on Maple Leaves that Look Like Tar<\/a>, Purdue Extension News
\nFind an Arborist<\/a>, International Society of Arboriculture
\nDiseases in Hardwood Tree Plantings<\/a>, The Education Store, Purdue Extension’s resource center
\nFifty Common Trees of Indiana<\/a>
\nAn Introduction to Trees of Indiana<\/a>
\nNative Trees of the Midwest<\/a>, The Education Store
\nShrubs and Woody Vines of Indiana and the Midwest<\/a>, The Education Store
\nTree Installation: Process and Practices<\/a>, The Education Store
\n<\/u>Planting Your Tree Part 1: Choosing Your Tree, Video<\/a>, Purdue Extension – Forestry & Natural Resource (FNR) YouTube Channel
\nInvesting in Indiana Woodlands<\/a>, The Education Store
\nForest Improvement Handbook<\/a>, The Education Store
\nID That Tree<\/a>, Purdue Extension-FNR YouTube playlist<\/p>\n

Purdue Plant and Pest Diagnostic Laboratory<\/a><\/p>\n

Diana Evans<\/a>, Extension and Web Communication Specialist
\nPurdue University Department of Forestry and Natural Resources<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

Question: we have several maple trees in our neighborhood afflicted with this black spot (see attached photo). What can we do to protect our maple trees? Anwer: while it is difficult to confirm a diagnosis from photos alone it looks and could be a fungal disease called tar spot. The most common species are Rhytisma […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[42,53],"tags":[60,913,1812,1811,1813,71],"class_list":["post-2365","post","type-post","status-publish","format-standard","hentry","category-forestry","category-urbanforestry","tag-forestry","tag-fungal-disease","tag-fungi","tag-maple-tree","tag-pesticides","tag-urban-forestry","audience-for-enthusiasts","audience-for-homeowners","audience-for-landowners","audience-for-professionals"],"acf":[],"aioseo_notices":[],"publishpress_future_action":{"enabled":false,"date":"2026-04-12 05:22:33","action":"change-status","newStatus":"draft","terms":[],"taxonomy":"category","extraData":[]},"publishpress_future_workflow_manual_trigger":{"enabledWorkflows":[]},"_links":{"self":[{"href":"https:\/\/www.purdue.edu\/fnr\/extension\/wp-json\/wp\/v2\/posts\/2365","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.purdue.edu\/fnr\/extension\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.purdue.edu\/fnr\/extension\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.purdue.edu\/fnr\/extension\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.purdue.edu\/fnr\/extension\/wp-json\/wp\/v2\/comments?post=2365"}],"version-history":[{"count":15,"href":"https:\/\/www.purdue.edu\/fnr\/extension\/wp-json\/wp\/v2\/posts\/2365\/revisions"}],"predecessor-version":[{"id":34562,"href":"https:\/\/www.purdue.edu\/fnr\/extension\/wp-json\/wp\/v2\/posts\/2365\/revisions\/34562"}],"wp:attachment":[{"href":"https:\/\/www.purdue.edu\/fnr\/extension\/wp-json\/wp\/v2\/media?parent=2365"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.purdue.edu\/fnr\/extension\/wp-json\/wp\/v2\/categories?post=2365"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.purdue.edu\/fnr\/extension\/wp-json\/wp\/v2\/tags?post=2365"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}