Canker
Symptom category — not a single disease
122 host plants · Fungal
Last updated
Data Coverage 3 of 6 dimensions
Cankers are sunken, elongated lesions on branches and trunks, often appearing as wounds that fail to heal normally. You'll notice the tissue around the canker may have a rough, cracked appearance, and the wood beneath often shows discoloration ranging from cinnamon-brown to dark black. On some hosts like poplars and willows, cankers can girdle branches and cause the section beyond to die back. In cool, moist climates, these lesions can persist for years, creating entry points for secondary pathogens and gradually weakening your trees.
Canker diseases are caused by fungi that exploit wounds and stressed areas on trees. Cold injury, storm damage, pruning wounds, and environmental stress all create openings for infection. The fungus colonizes the cambium and conducts vascular tissues, cutting off nutrient and water flow. Management focuses on prevention and clean pruning practices: avoid wounding trees during the growing season; space seedlings and young trees well apart for good air circulation; don't over-fertilize or irrigate late in the season, which creates succulent growth more prone to damage; and when you must prune, do so during dormancy and sterilize tools between cuts to avoid spreading spores between plants.
Quick Reference
Agent Type
fungal
Causal Agent
Symptom category — not a single disease
Host Plants
122
Management
Cultural Controls
- Maintain plant vigor through proper watering, mulching, and fertilization. Stressed plants are more susceptible.
- Avoid wounding during the growing season. Prune during dry weather when possible.
- Sanitize pruning tools between cuts with 70% isopropyl alcohol or 10% bleach.
- Prune cankered branches at least 6 inches below the visible canker margin into healthy wood.
- Remove and destroy severely infected plants to reduce inoculum.
- Protect trunks from winter injury with white trunk paint or tree guards on thin-barked species.
Host Plants (122)
Acer crataegifolium Hawthorn, Maple Arbutus menziesii Pacific Madrone Arbutus unedo Strawberry Tree, Killarney Strawberry Tree, Madroño Betula alleghaniensis Yellow Birch Betula davurica Asian Black Birch, Dahurian Birch Betula glandulosa Dwarf Birch Bog Birch, Scrub Birch Betula lenta Sweet Birch, Cherry Birch, Black Birch Betula maximowicziana Monarch Birch Betula nigra River Birch, Black Birch Betula occidentalis Water Birch, Western Birch, Red Birch, River Birch, Black Birch Betula papyrifera Paper Birch Betula pendula European White Birch Betula platyphylla Asian White Birch, Manchurian Birch Betula populifolia Gray Birch, Fire Birch Betula pubescens Downy Birch, Moor Birch Betula utilis Himalayan Birch, Bhojpatra, Indian Paper Birch Betula utilis subsp. albosinensis Chinese Paper Birch, Chinese Red Birch Betula utilis subsp. jacquemontii Whitebarked Himalayan Birch Buxus bodinieri Bodinier's Boxwood Buxus microphylla Buxus microphylla Buxus sempervirens Common Boxwood, Common Box European Box Cedrus libani subsp. brevifolia Cypress Cedar, Cyprian Cedar Corylus americana American Hazel, American Filbert Corylus avellana Common Filbert Corylus chinensis Chinese Hazel Corylus colurna Turkish Hazel Corylus cornuta var. californica Western Hazel, California Hazel, Western Beaked Hazel Corylus heterophylla Siberian Hazelnut Asian Hazel Crataegus ambigua Russian Hawthorn Crataegus autumn Crataegus autumn Crataegus columbiana Columbia Hawthorn Crataegus crus Crataegus crus Crataegus douglasii Black Hawthorn Crataegus germanica Medlar Crataegus laevigata English Hawthorn Crataegus lavallei Lavalle Hawthorn, Carrierei Hawthorn Crataegus monogyna Singleseed Hawthorn, Common Hawthorn, English Hawthorn Crataegus phaenopyrum Washington Hawthorn Crataegus punctata Dotted Hawthorn, Flat-topped Hawthorn Crataegus viridis Green Hawthorn,Southern Hawthorn Cupressus arizonica Arizona Cypress, Rough-bark Arizona Cypress Cupressus bakeri Baker Cypress, Modoc Cypress Cupressus dupreziana Saharan Cypress, Tassili Cypress, Duprez Cypress Cupressus glabra Smooth Arizona Cypress Cupressus guadalupensis Guadalupe Cypress Cupressus lusitanica Mexican Cypress Cupressus macrocarpa Monterey Cypress Cupressus sempervirens Italian Cypress, Mediterranean Cypress Gleditsia macracantha Large Spined Honeylocust Gleditsia triacanthos Honeylocust Gleditsia triacanthos var. inermis Thornless Honeylocust Paxistima myrsinites Oregon Boxwood, Mountain Lover Pinus albicaulis Whitebark Pine, Scrub Pine, White Pine Pinus aristata Bristlecone Pine, Rocky Mountain Bristlecone Interior Bristlecone Pinus attenuata Knobcone Pine Pinus banksiana Jack Pine, Scrub Pine, Banksian Pine, Hudson Bay Pine Pinus bungeana Lacebark Pine, Whitebark Pine, Baipi Song Pinus canariensis Canary Island Pine Pinus cembra Swiss Stone Pine Pinus contorta Lodgepole Pine Pinus contorta var. contorta Shore Pine Pinus contorta var. latifolia Rocky Mountain Lodgepole Pine Pinus coulteri Coulter Pine, Bigcone Pine Pinus densiflora Japanese Red Pine Pinus edulis Pinyon Pine, Piñón Pine, Two-needle Pinyon Colorado Pinyon Pinus elliottii Slash Pine, Swamp Pine Pinus flexilis Limber Pine, Rocky Mountain White Pine Pinus halepensis Aleppo Pine, Jerusalem Pine Pinus heldreichii Bosnian Pine, Snakeskin Pine Pinus jeffreyi Jeffrey Pine, Western Yellow Pine, Bull Pine Pinus kwangtungensis Kwangtung Pine, Guangdong Pine Pinus lambertiana Sugar Pine Pinus leucodermis Bosnian Pine Pinus monophylla Singleleaf Pinon Pine, One-leaved Pine Pinus monticola Western White Pine Pinus mugo Mugo Pine Pinus mugo var. pumilio Mugo pine, Dwarf Mugo pine Pinus nigra Austrian Pine Pinus parviflora Japanese White Pine Pinus parvifola Pinus parvifola Pinus pinaster Maritime Pine, Cluster Pine, Turpentine Pine Pinus pinea Italian Stone Pine, Umbrella Pine Pinus ponderosa Ponderosa Pine, Western Yellow Pine Pinus pumila Japanese Stone Pine, Dwarf Siberian Pine Pinus radiata Monterey Pine Pinus resinosa Red Pine Pinus sabiniana Gray Pine, Foothill Pine Pinus strobiformis Southwestern White Pine, Mexican White Pine, Chihuahua White Pine Pinus strobus Eastern White Pine Pinus sylvestris Scots Pine, Scotch Pine Pinus thunbergii Japanese Black Pine Pinus virginiana Virginia Pine, Scrub Pine, Jersey Pine Pinus wallichiana Himalayan Pine, Bhutan Pine Pinus yunnanensis Yunnan Pine Populus alba White Poplar European White Poplar, Silver Poplar Populus angustifolia Narrowleaf Cottonwood, Mountain Cottonwood Populus balsamifera Balsam Poplar Populus canescens Gray Poplar Populus deltoides Eastern Cottonwood Populus fremontii Fremont Cottonwood, Western Cottonwood Populus grandidentata Bigtooth Aspen Populus nigra Black Poplar Populus tremula European Aspen European Trembling Aspen European Quaking Aspen Populus trichocarpa Black Cottonwood Quercus phellos Willow, Oak Salix alba Salix alba Salix babylonica Weeping Willow Salix caprea Salix caprea Salix integra Salix integra Salix magnifica Magnolia-leaf Willow, Magnificent Willow Salix matsudana Salix matsudana Salix pentandra Laurel, Willow, Bay Willow Salix phlebophylla Skeletonleaf Willow Salix purpurea Purpleosier Alaska Blue Willow Salix scouleriana Scouler's Willow Tilia americana American Linden, American Basswood Tilia cordata Littleleaf Linden Tilia euchlora Crimean Linden Tilia europaea European Linden, Common Linden Common Lime European Basswood Tilia mongolica Mongolian Linden, Mongolian Basswood Tilia tomentosa Silver Linden, Silver Basswood Viburnum dilatatum Linden, Viburnum, Linden, Arrowwood