{"id":25859,"date":"2023-10-30T11:53:39","date_gmt":"2023-10-30T15:53:39","guid":{"rendered":"https:\/\/www.purdue.edu\/fnr\/extension\/?p=25859"},"modified":"2025-06-03T11:51:28","modified_gmt":"2025-06-03T15:51:28","slug":"inonotus-dryadeus-butt-and-root-rot-of-oaks","status":"publish","type":"post","link":"https:\/\/www.purdue.edu\/fnr\/extension\/inonotus-dryadeus-butt-and-root-rot-of-oaks\/","title":{"rendered":"Inonotus Dryadeus, Butt and Root Rot of Oaks-Purdue Landscape Report"},"content":{"rendered":"
\"declining<\/a>

Figure 1: Mature oak tree known to be infected by Inonotus dryadeus on Purdue University West Lafayette campus. Right image shows limb death suggestive of tree decline.<\/p><\/div>\n

Purdue Landscape Report:<\/a> Inonotus dryadeus\u00a0<\/em>is one of the more common wood decay fungi we receive at the diagnostic lab in association with declining trees, specifically oaks.\u00a0Inonotus<\/em>\u00a0is found so frequently on oaks it has the common name oak bracket fungus, but it can cause root rot of a number of other hardwood trees (including maples, sweet gum, buckeyes, chestnut, and ash) and conifers (fir, pines, spruce, and hemlock \u2013 mostly in western US).<\/p>\n

Similar to other butt and root rots of trees,\u00a0Inonotus\u00a0<\/em>causes internal decay near the base of the tree. Trees may not show any external symptoms while there is a raging root rot decaying everything holding it up, eventually leading to an unexpected failure of the tree during a windstorm. Trees with compromised root systems may also die suddenly during hot and dry weather. Most often, we see a gradual decline of infected trees with stunted growth, limb dieback, and\/or sparse, off-color foliage; symptoms that may accelerate during adverse environmental conditions (Figure 1).<\/p>\n

<\/div>\n

The only good thing about this fungus is that it is somewhat easy to identify.\u00a0Inonotus<\/em>\u00a0produces a round to irregularly-shaped conk like structure each year from colonized host tissue, such as exposed roots, the trunk at the soil-line, or lower trunk (Figure 2). When it is young the conk is yellow to orange on the upper surface and white on the underside. Pores in the upper surface of the conk producing amber colored liquid can also be found earlier in the spring and early summer, lending to its other common name the weeping conk (Figure 3).<\/p>\n

\"growth<\/a>

Figure 2: Extensive growth of Inonotus dryadeus from the base of an oak tree. The tree had significant limb dieback, was at risk of falling over, and subsequently removed.<\/p><\/div>\n

\"early<\/a>

Figure 3. Inonotus conks with amber droplets on their upper surface.<\/p><\/div>\n

\n

To view this full article and other Purdue Landscape Report articles, please visit Purdue Landscape Report<\/a>.<\/p>\n

Subscribe and receive the newsletter: Purdue Landscape Report Newsletter<\/a>.<\/p>\n

Resources:
\n<\/strong>Root Rot in Landscape Plants<\/a>, The Education Store, Purdue Extension resource center
\nDead Man’s Fingers<\/a>, Purdue Landscape Report
\nID That Tree Fall Color: Sugar Maple<\/a>, Purdue Extension \u2013 Forestry and Natural Resources (FNR) YouTube Channel
\nID That Tree Fall Color Edition: Black Gum<\/a>, Purdue Extension \u2013 FNR YouTube Channel
\nAn Introduction to Trees of Indiana<\/a>, The Education Store
\nAutumn Highlights Tour \u2013 South Campus<\/a>, Purdue Arboretum Explorer
\nSubscribe<\/a>, Purdue Extension – FNR YouTube Channel
\nTree Defect Identification<\/a>, The Education Store
\nTree Wound and Healing<\/a>, Got Nature? Blog, Purdue Extension \u2013 FNR
\nShrubs and Woody Vines of Indiana and the Midwest<\/a>, The Education Store
\nAsk an Expert: Tree Selection and Planting<\/a>, Purdue Extension – FNR YouTube playlist
\nID That Tree<\/a>, Purdue Extension – FNR YouTube playlist
\nInvasive Species<\/a>, Playlist, Purdue Extension – FNR YouTube Channel
\nReport Invasive Species<\/a>, Purdue Invasive Species
\nFind an Arborist<\/a>, International Society of Arboriculture<\/p>\n

John Bonkowski<\/a>, Plant Disease Diagnostician
\nDepartments of Botany & Plant Pathology<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

Purdue Landscape Report: Inonotus dryadeus\u00a0is one of the more common wood decay fungi we receive at the diagnostic lab in association with declining trees, specifically oaks.\u00a0Inonotus\u00a0is found so frequently on oaks it has the common name oak bracket fungus, but it can cause root rot of a number of other hardwood trees (including maples, sweet […]<\/p>\n","protected":false},"author":58,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[38,870,42,49,54,622],"tags":[1812,1866,504,895,1867],"class_list":["post-25859","post","type-post","status-publish","format-standard","hentry","category-alert","category-disease","category-forestry","category-plants","category-wildlife","category-woodlands","tag-fungi","tag-inonotus-dryadeus","tag-oak","tag-purdue-landscape-report","tag-wood-decay","audience-for-enthusiasts","audience-for-homeowners","audience-for-landowners","audience-for-professionals"],"acf":[],"aioseo_notices":[],"publishpress_future_action":{"enabled":false,"date":"2026-04-17 08:46:09","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\/25859","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\/58"}],"replies":[{"embeddable":true,"href":"https:\/\/www.purdue.edu\/fnr\/extension\/wp-json\/wp\/v2\/comments?post=25859"}],"version-history":[{"count":17,"href":"https:\/\/www.purdue.edu\/fnr\/extension\/wp-json\/wp\/v2\/posts\/25859\/revisions"}],"predecessor-version":[{"id":33244,"href":"https:\/\/www.purdue.edu\/fnr\/extension\/wp-json\/wp\/v2\/posts\/25859\/revisions\/33244"}],"wp:attachment":[{"href":"https:\/\/www.purdue.edu\/fnr\/extension\/wp-json\/wp\/v2\/media?parent=25859"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.purdue.edu\/fnr\/extension\/wp-json\/wp\/v2\/categories?post=25859"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.purdue.edu\/fnr\/extension\/wp-json\/wp\/v2\/tags?post=25859"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}