Elm Tree Diseases Symptoms and Treatments
Prevent your elm tree from rapid decline and death due to disease. Knowing how to identify and treat elm tree diseases will help you keep them healthy and thriving.
72tree.com assembled the following elm tree disease information, symptoms, and what treatments can help you save them from decline and death.
Elm Tree Disease
The following are some of the more common diseases that affect elm trees (Ulmus) and the treatments used to stop them from killing the trees.
Dutch Elm Disease (DED)
This disease was introduced to the U.S. in the 1930s and has since decimated the American elm (Ulmus americana) population. All native elms and European elms are susceptible, and the disease, 90 years later, still poses a significant threat.
Dutch elm disease is caused by two closely related fungi species (Ophiostoma ulmi and Ophiostoma novo-ulmi), the latter being responsible for most of the disease’s devastation. This fungus species attacks the elm’s vascular system. The tree, in turn, tries to stop the spread of the fungus by producing tyloses (plug-like structures) that block the flow of water and nutrients, contributing to the tree’s demise.
Dutch Elm Disease Symptoms Include:
• Premature leaf drop.
• The first symptom in infected trees usually appears as a small yellow or brown wilting area of foliage referred to as “flagging,” often starting at the edge of the crown.
• Wilting rapidly spreads inward toward the trunk.
• Leaves wilt, yellow, and eventually turn brown.
• Branch death.
• Brown streaking in sapwood (revealed by removing the bark or by cutting a cross-section of the dying branch).
This disease advances very fast. Depending on the health of the tree and time of infection, Dutch elm disease can lead a healthy adult elm tree to its death in a single growing season.
Dutch Elm Disease Treatment:
• Extensive pruning of infected areas.
• Remove severely infected trees.
• Burn or bury all infected wood (kills beetle larvae).
• Sever root graphs (connections) with neighboring trees.
• Preemptively treat uninfected trees with pesticides targeting elm bark beetles.
• Sterilize all pruning and maintenance equipment and materials after contact with infected trees.
• Create bait trees by treating them with cacodylic acid, killing the tree, and luring the fungus carrying beetles (this method suppresses brood production, making the beetle more manageable).
• Apply anti-fungal sprays to areas where infected trees are or have been.
• Plant DED resistant cultivars.
Note: If Dutch elm disease is caught early enough, extensive pruning may save the tree.
Multiple DED-resistant American elms and hybrid elm species are currently available and being developed. Some disease-resistant cultivars include:
• Morton Glossy
• Morton Stalwart
• New Horizon
• Valley Forge
Tip: Hire an ISA certified arborist to accompany or supervise all DED treatment strategies.
Elm Yellows (Formerly Elm Phloem Necrosis)
Elm yellows is an aggressive disease affecting elm trees that is spread via root grafts or leafhoppers. Also known as elm phloem necrosis, the disease is fast-moving, has no cure, and occurs principally in the eastern United States and southern Ontario.
This disease is caused by phytoplasmas that infect the tree’s phloem (inner bark). This infection quickly kills the tree’s phloem, girdling the tree and stopping its flow of water and nutrients.
Elm Yellows Symptoms Include:
• Root debilitation (root hairs die).
• The phytoplasma infection kills the phloem (causing it to change color and take on a wintergreen-like smell.
• Inner bark tissues exhibit butterscotch or light brown discoloration, usually in streaks.
• The crown will turn yellow and droop all at once.
• Leaf drop and death of branches.
Inner bark tissue discoloration may occur in branches, twigs, and the trunk on DED infected trees, where discoloration caused by elm yellows is more commonly found in the trunk.
Elm yellows symptoms can appear any time during the summer but are most common in mid-to late-summer.
Elm Yellows Disease Treatment:
• There is no cure for this disease. Once a tree exhibits signs of elm yellows, it is highly recommended to remove and destroy the tree. Thus, eliminating inoculum sources from the area.
• Thorough root removal after felling an infected tree.
• Control or management of phloem-feeding insects like leafhoppers and spittlebugs.
• Topical application of pesticides to deter insect feeding.
• Apply anti-fungal sprays to areas where infected trees are or have been.
Plant Asian and European elm species in areas where elm yellows is present. These cultivars exhibit resistance to this disease.
Note: Elm yellows does not move into new areas as quickly as Dutch elm disease, providing a larger window for infected tree removal, preventive treatments, and containment.
Laetiporus root rot (formerly Polyporus sulfureus)
As elm trees age, the damage inflicted by butt and root rot fungi can severely compromise their structural stability. Failure eventually occurs during strong winds or severe weather, often without warning, resulting in severe property or physical damage. Root and butt rot can be caused by one of many wood-decaying fungal pathogens, but one of the more commonly occurring in elm trees is Laetiporus sulphureus.
Laetiporus Root Rot Symptoms Include:
• Canopy dieback.
• Stunted shoots.
• Undersized or pale-colored foliage.
• Premature fall color change
• Clusters of yellow to salmon to orange, shelf-like fruiting structures (conks) that turn white with age form in summer or autumn months on the trunk near the ground and fall off during the winter.
• The conk’s underside has tiny pores in which millions of spores are formed.
• New conks form in the following summer and autumn months. The bark where the fruiting structures form will be slightly depressed and often cracked.
Root and butt rot fungi damage may only be exposed when trees suffer windthrow or windsnap during strong winds or severe weather. In some cases, Root and butt rot symptoms are present but provide little to no information on the depth of decay in the roots and lower trunk.
Laetiporus Root Rot Treatment:
• Root rot, in nearly all instances, is a case for immediate tree removal. Especially when fruiting structures are present at the trunk base or on the root flare.
• Hire an ISA certified arborist to evaluate the infected tree and recommend a course of action.
Note: Tree root diseases can be best controlled by preventive measures. When planting new elm trees, select disease-resistant cultivars, only plant in well-drained soil, and avoid overwatering. Chemicals, like chloropicrin or methyl bromide, don’t cure the disease but can reduce the level of the infection. Such fumigants work best when applied in and around the base of an infected tree or in the hole left behind after tree removal.
What is Killing My Elm Trees?
In this article, you discovered information on some of the more deadly elm tree diseases, the signs they display, and how to treat or control them.
Knowing how to recognize and treat elm tree diseases can help you catch and treat a disease early enough to potentially save your tree.
Ignoring the signs of a diseased elm tree can result in catastrophic damages when that tree falls on your home or causes personal injuries.
Tree Root Rot Causes, Symptoms, and Treatments
Don’t let root rot cause your trees to suddenly decline, die, and fall. Knowing how to identify root rot symptoms will help you save your tree or take action before it causes catastrophic property damages.
72tree.com gathered information on the causes of root rot in trees, how to recognize its symptoms, and what treatments you can use to stop or prevent it.
Tree Root Rot Causes
When root rot attacks a tree, the flow of water and nutrients from the roots to the crown is either impeded, or the invading pathogen is carried throughout the tree, killing its host. The following are several of those pathogens:
Rhizoctonia (this fungal pathogen adversely affects younger hosts, older trees are found to be more resistant)
Pythium (this fungus of the Pythiaceae family has 140 known species, most of which are now classified as parasites)
Rhododendron Root Rot (Phytophthora cactorum and Phytophthora cinnamomi were first thought to only survive in subtropical countries but is now known to thrive in cooler countries)
Fusarium (found worldwide, some of this pathogen’s species can adversely affect humans when infected crops are consumed)
Rosellinia necatrix (Dematophora necatrix, Hypoxylon necatrix, and Pleurographium necator, known as one of the most devastating plant fungal diseases, affecting several fruit tree and crop species)
Honey Fungi, Shoestring Root Rot, or Openky (Armillaria frequently occurs in hardwoods and pines)
Texas Root Rot (Phymatotrichopsis, Phymatotrichum, Cotton, or Ozonium root rot occurs more frequently in Mexico and the southwestern United States, causing sudden wilt and death)
Note: Fungal spores naturally occur and lie dormant in soil. These spores only begin reproducing when conditions support it. Such conditions include compacted soil, poorly-drained soil, and overwatering. As the fungi reproduce, tree roots provide a prime source of nutrients, allowing them to spread quickly.
Symptoms of Tree Root Rot
Most visible symptoms of root rot strikingly resemble the signs of an advanced pest infestation, making an accurate diagnosis more difficult. The most common, above ground, symptoms of root rot include:
• Gradual or sudden decline without a detectible reason
• Severely stunted or poor growth patterns
• Smaller, chlorotic leaves or needles (new growth)
• Wilted, yellowed, or browned leaves or needles
• Severe canopy thinning
• Stress crops (abnormally large amount of fruit/seeds)
• Fungal fruiting structures (mushrooms) found on the root flare or growing from surface roots
• Once in the xylem and phloem (cambium), cankers or sunken dead areas may appear on branches or the trunk of the host
A more accurate way to diagnose root rot is to dig to the roots to see if decay is present. Care should be taken when exposing roots to avoid inflicting further harm to the tree.
Note: Anthracnose is another group of fungal pathogens that cause similar above-ground tree damage but are not typically associated with root rot. You can find further information about anthracnose at 72tree.com/symptoms-of-anthracnose/
Tip: Hire an ISA certified arborist to inspect and accurately diagnose the cause(s) of the symptoms you have identified.
Tree Root Rot Treatment
Trees can sometimes be saved early on by pruning out infected roots. If a tree is in an advanced state of decline, the recommended way to control root rot diseases from spreading is to entirely remove it.
Chemical treatments that include propiconazole, chloropicrin, fosetyl-aluminum, or methyl bromide, among others, won’t completely cure or remove the disease but can reduce the infection level. These treatments are applied in and around the root plate of infected trees and especially in holes left after infected trees, and their stumps have been removed.
Note: The application of chemical treatments on your trees (for any reason) should be performed as directed on the product labeling and closely monitored by a certified arborist.
Root Rot Prevention for Trees
Trees have adapted over millennia to protect themselves against infection and illness. They are efficient at protecting themselves when healthy, and you can further assist them in resisting root rot by:
• Avoiding overwatering
• Ensuring proper water drainage by amending/enriching soil structure
• Preventing soil compaction on or around the root plate
• Protecting surface roots and trunks from mechanical and/or equipment damage
• Immediately addressing storm damage and/or soil erosion
• Removing unsalvageable trees from your property
• Planting disease-resistant species
Tip: You can also help trees fight fungal attacks by promoting their health. These are some of the things you can do to improve their health:
• Seasonal pruning
• Seasonally applying and refreshing organic mulch
• Deep watering (especially during drought conditions)
• Pre-growing season fertilization
• Annual tree inspections by a certified arborist
Note: The importance of annual tree inspections cannot be overstated. The ability to detect problems in their beginning stages offers more options to eliminate existing problems and take measures to prevent issues throughout the tree’s growing season.
Tree Root Rot
In this article, you discovered valuable information about the causes of tree root rot, recognizing its symptoms, and how to treat it or prevent it.
Taking swift action when root rot is suspected in your trees will increase your chances of saving them and preventing further infection.
Ignoring the signs of root rot will render your tree unsalvageable, invite other disease and infestation, and potentially cause catastrophic property damage when your tree destabilizes and falls.
Common Maple Tree Diseases, Symptoms, Treatment, and Prevention
Stop your maple tree from needlessly dying. If caught in time, diseases that attack maples can be treated with success.
72tree.com of Alpharetta Ga, assembled the following list of diseases that affect maple trees, how to identify, treat, and prevent them.
Why do My Maple Tree Leaves Have Spots?
One of the easiest ways to detect maple tree diseases is through irregularities in shape or size, spots, and/or blemishes on the tree’s foliage.
The following diseases may cause spots to appear on your maple tree’s foliage:
Leaf Spot (Phyllosticta minima) – This fungal infection causes round spots about a quarter of an inch in diameter to appear on leaves. These spots will have a pronounced purple border and blackish dots in the center of the spot (fungal fruiting structures).
Treatment: Before fall, prune dead twigs, stems, and branches. Collect all clippings and destroy them (burning them is highly recommended) to prevent the spread of the fungus.
Have the tree evaluated to determine the extent of the infection and whether further action like using fungicides should be taken to protect your tree and surrounding landscape.
NOTE: Sanitize all equipment, including gloves and protective clothing that come in contact with an infected tree and its foliage.
Anthracnose (Aureobasidium apocryptum or Discula – Gloeosporium) – Anthracnose is a fungal infection that causes purple or brown streaks to occur alongside and between leaf veins. In some maple species, drought and heat stress can produce similar symptoms. You can confirm an anthracnose infection by locating small, brown fungal fruiting structures near the veins of affected leaves.
Treatment: The same measures and precautions for leaf spot should be used in the treatment of anthracnose.
NOTE: Anthracnose can lead to severe defoliation during a wet spring season.
Root Rot (Fomes fomentarius, Ganoderma lucidum, or Laetiporus sulfureus) – Once a fungal infection embeds itself in the trunk or the roots of a maple tree, there are three types of symptoms to watch for:
• Foliage in the entire crown or a section of it may suffer from chlorosis, wilt, die and eventually fall. This happens as the fungi cause hydraulic failure within the roots, trunk, and branches.
• Fungal fruiting structures (mushroom conks) will appear from late spring to mid-fall. For these structures to form, there must be rotting organic material within the tree.
• Large black ants known as carpenter ants will make a nest for their colony within trees that suffer from heart rot. These ants do not burrow through heartwood, they remove the tissues rotting and softened from the infection.
Treatment: Once root rot or heart rot has been confirmed, have the tree professionally removed as quickly as possible.
NOTE: The presence of carpenter ants and fungal fruiting structures only occur after significant damage has been done to the tree. When the affected tree is within striking distance of your home, places where people congregate, or other structures and vehicles, the situation should be treated as an emergency.
Galls – These spots are irregular growths or swellings that occur from a reaction to tissue feeding or egg-laying by various species of mites and insects (commonly mistaken for fungal infection).
Galls appear in various ways. Each mite or insect species produces a distinctive gall shape and can range from wart-like bumps to felt-like patches to spindle-shaped protrusions. Galls develop in the spring, and once formed, the pest remains protected within the structure. Arborists can often identify which mite or insect has infested your tree by the shape and appearance of the galls.
Treatment: Leaf galls are relatively innocuous and rarely result in any long term damage to the tree. Applications of pesticides are relatively ineffective, as the pests are protected within the gall structure.
The most effective manner of gall removal is to handpick and destroy affected foliage before exit holes form and allow the pest(s) to move on. If the presence of galls is overwhelming, hire a professional tree service to evaluate the situation and recommend a course of action.
Maple Tree Disease Prevention
Maple tree disease prevention begins with good tree care practices. The healthier your tree is, the more vigorously it can fight back against diseases and infestations.
However, when the tree’s defenses fail, here are steps to prevent the disease or infestation from infecting surrounding trees:
• Prune affected limbs (before leaf-drop)
• Burn all pruned limbs and foliage
• Always sanitize pruning equipment after use on an infected tree
• Avoid tracking soil from around infected trees to areas around uninfected trees (many fungi and other pathogens thrive in the soil). Clean boots, protective clothing, tools, and equipment before leaving an infested area
• Replant resistant species after tree removal
• Avoid planting maple trees in areas with a history of tree diseases
• Have annual tree inspections and soil testing performed to detect any issues early on.
Black Spots on Maple Leaves
In this article, you discovered how to identify diseases that cause spots on maple tree leaves, how to treat them, and how to prevent them.
Prevent the decline of your maple tree by knowing what to do when a fungus or pathogen begins showing signs of infection.
Your choice to ignore signs that your tree is diseased or in decline can result in catastrophic fungal outbreaks to your landscape, or costly damages to your property when the tree falls.