DISEASETREE SPECIES AFFECTEDWHAT IS IT?PREVENTIONCONTROL
Anthracnoseashes, oaks, maples, basswood, dogwoodsA fungal disease causing discolouration of leaves and possibly defoliation. Anthracnose does not cause permanent damage, but can weaken the tree.do not overhead water, i.e. water with sprinkler; ensure adequate air circulation around leaves and stems; plant in well-drained soil and mulch and water in dry conditionsrake up leaves and prune out dead and dying branches, a source for re-infection in the following season and remove from site; can be included with city-collected yard waste
Blight Diseasesserviceberry, basswood, pinesA fungal or bacterial disease affecting flowers, leaves, and shoots causing young growth to turn black or brown and curl up.avoid overfeeding and severe pruningin summer, remove limbs, cutting well outside infected area (6-12) and dispose
for severly infected trees, contact a certified arborist
Cankercherries, ashes, redbud, white pine, oaks, maples, basswood, spruceFungal diseases where the infected wood swells and cracks open. A thickened callus may form around the infected area. Can cause branch dieback.avoid wounding treesremove cankerous tissue in dry weather and prune away infected areas
protect trunks from sunscaldmake sure to clean tools between cuts to prevent spread of disease
prevent drought and flooding
Downey MildewviburnumsA fungal disease visible by a lightly coloured growth on underside of leaf and angular spots of dead tissue between leaf veinsavoid overhead irrigation in springrake leaves in autumn and remove from site
Gallsmaples, oaks, cherries, basswoodCertain bacteria, fungi, insects, and viruses induce the development of swollen plant tissue. Severely infected leaves are distorted.attract predatory birds and other beneficial organisms to your yard - these will depend on which insect or mite is causing the problemthe majority of galls are cosmetic in nature and do not cause significant damage to the tree - tolerate them, don't spray
determine which type of gall to determine action
for oaks and pines, prune out and destroy galls when they occur
Needlecastpines and sprucesA fungal disease of conifers. Most trees recover the following year, producing new, healthy growth.plant trees where there is good air circulationprune off damaged tips
protect young trees from winter frost and windsrake up dropped needles and remove from site
Powdery Mildewhackberry, serviceberry, viburnums, oaks, maples, tulip treeA fungal disease which leaves a powdery covering on infected leaves. Many fungi cause this disease most can only infect one or a few plant species. provide good soil drainage and air circulationspray with garlic spray
remove plant parts that show symptoms and dispose
Sooty Moldtulip tree, nannyberry, maple, alder, birch, dogwood, basswoodThis is not a pathogen, but merely fungal growth on honeydew secreted by aphids higher up on tree which has dripped onto the lower leavescontrol aphids with mild soap spray
Wiltmaples, redbud, oaksA fungal tree disease which plugs the water conducting vessels and greatly reduces the flow of water up the stem of the tree.provide adequate watering and compostingprune out diseased branches
do not plant another tree of same species in the infected soilfeed diseased tree with a high nitrogen fertilizer like bonemeal
where there are multiple trees of same species in close proximity and one is infected, contact a certified arborist to control spread of disease
Fire BlightserviceberrySudden wilting an ddeath of branch tips. Bark appears shrivelled and blossoms wilt, turn black, and hang on the twig.Do not fertilize with high nitrogen fertilizerprune out and remove infected woods
disinfect tools between cuts
Leaf Spotserviceberry, tulip tree, ashes, hackberryGeneral term for fungal diseases caused by a number of different pathogens for which spotting on leaves is the predominate symptom. Anthranose and tar spot are examples of leaf spot disease.do not overhead water - use a hose, not a sprinkler; reduce humidity between plants by providing adequate space between plants and by pruning lower branchesremove and dispose of spotted leaves on plants that have fallen
reduce humidity between plants by providing adequate space between plants and by pruning lower branches
use mulch under trees
Leaf BlisteroaksA fungal disease of oaks that appears as yellow-white blisters up to 1/2"" in diameter on upper leaf surface, with corresponding yellowish brown depression on leaf undersides. Numerous spots will cause leaf to fall prematurely, but does not seriously affect tree health.maintain plant vigourcollect fallen leaves and remove from site
Rust Diseasesashes, oaks, serviceberries, pinesA fungal disease that causes leaves to become distorte and twigs to swell. Powdery yellow-orange spots may be present on undersides of leaves. Life cycle of fungus requires evergreens as alternative host.do not plant both hosts near each other, i.e. do not plant serviceberry near juniperkeep tree well watered and increase soil organic matter
rake up leaves and fallen branches in fall and remove from site
hand pick or prune out galls on evergreens before they swell