Trees and problems in mn
Despite providing our trees and shrubs with all their necessities, diseases and insects can still cause problems. In most cases, however, healthy mature trees and shrubs are able to defend themselves against minor insect and fungal disease exposure without intervention by us.
Trees and shrubs can tolerate substantial foliar loss caused by feeding by insects or foliar fungal disease. In fact, healthy plants can have every single leaf eaten off and still survive! Plants have latent buds which do not sprout into leaves unless needed. So, of a leaf is eaten away or extensively damaged by a disease, the latent bud sprouts to form a new leaf. If a leaf is only half eaten away, the remaining green tissue will continue to conduct photosynthesis and provide food for the plant. Because trees and shrubs have so many leaves, loosing a few, or parts of many leaves, is really not harmful.
However, if a tree or shrub is subjected to repeated defoliation by insects or disease, it can stress the plant and make it more susceptible to infestation by other diseases and insects. Severe, repeated insect or fungal infestation may warrant treatment.
Diseases and Insects are less likely to attack healthy trees and shrubs. However, a plant that is already under stress for some reason, such as drought, flooding, climate, poor pruning, etc., is much more likely to have problems with insects or diseases.
Young, newly planted trees may also be at higher risk for damage from diseases or insects. While large trees are usually able to handle the stress of defoliation by fungal diseases or insect feeding, young trees with few leaves are more susceptible to long-term damage. Because young newly planted trees are already stressed from being transplanted, insecticide or fungicide treatments may be warranted to reduce further stress.
Diseases and Environmental Problems
A wide variety of problems can afflict trees and shrubs, including diseases caused by microorganisms such as fungi and bacteria (biotic), or symptoms caused by environmental or cultural conditions (abiotic). Keeping a close eye on plants will allow you to detect problems early, when remedies will be most effective. If a plant is unhealthy, some detective work is in order to determine the cause.
Diagnosing Plant Problems
In many cases, similar symptoms can be caused by a wide variety of reasons. It is important to carefully assess an unhealthy plant to narrow down the cause of the problem. Often, a tree or shrub is suffering from more than one problem--a stressed plant is often the target of secondary invaders which may not have taken hold had the plant been healthy. In addition to insects, trees and shrubs are the victims of diseases, poor fertility, climate extremes, incorrect soil moisture conditions, environmental pollution (air, soil or water), and physical injuries.
"Symptoms" are displayed on the plant as a result of a biotic or abiotic problem. It isn't possible to see the organism itself, but you can see the plant's response to the problem. For example, wilting leaves may be the result of a root rot fungus that is preventing the roots from taking up moisture. You see the symptom--wilting leaves--but not the fungus itself.
"Signs" are direct evidence of the cause of the disease. You may see mushrooms growing around the base of the plant. You see actual parts of the fungus--mushrooms--that is causing the root rot.
When assessing an unhealthy plant, look for any and all symptoms and signs that may be present. Thoroughly observe the leaves, stems, branches, trunk and, if possible, roots.
Consider the history of the plant, since often symptoms do not appear until years after the cause. For example, construction damage to a large tree's roots may not cause dieback or tree death for several years, as the tree tries to hang on and grow new roots.
Trees and shrubs can tolerate substantial foliar loss caused by feeding by insects or foliar fungal disease. In fact, healthy plants can have every single leaf eaten off and still survive! Plants have latent buds which do not sprout into leaves unless needed. So, of a leaf is eaten away or extensively damaged by a disease, the latent bud sprouts to form a new leaf. If a leaf is only half eaten away, the remaining green tissue will continue to conduct photosynthesis and provide food for the plant. Because trees and shrubs have so many leaves, loosing a few, or parts of many leaves, is really not harmful.
However, if a tree or shrub is subjected to repeated defoliation by insects or disease, it can stress the plant and make it more susceptible to infestation by other diseases and insects. Severe, repeated insect or fungal infestation may warrant treatment.
Diseases and Insects are less likely to attack healthy trees and shrubs. However, a plant that is already under stress for some reason, such as drought, flooding, climate, poor pruning, etc., is much more likely to have problems with insects or diseases.
Young, newly planted trees may also be at higher risk for damage from diseases or insects. While large trees are usually able to handle the stress of defoliation by fungal diseases or insect feeding, young trees with few leaves are more susceptible to long-term damage. Because young newly planted trees are already stressed from being transplanted, insecticide or fungicide treatments may be warranted to reduce further stress.
Diseases and Environmental Problems
A wide variety of problems can afflict trees and shrubs, including diseases caused by microorganisms such as fungi and bacteria (biotic), or symptoms caused by environmental or cultural conditions (abiotic). Keeping a close eye on plants will allow you to detect problems early, when remedies will be most effective. If a plant is unhealthy, some detective work is in order to determine the cause.
Diagnosing Plant Problems
In many cases, similar symptoms can be caused by a wide variety of reasons. It is important to carefully assess an unhealthy plant to narrow down the cause of the problem. Often, a tree or shrub is suffering from more than one problem--a stressed plant is often the target of secondary invaders which may not have taken hold had the plant been healthy. In addition to insects, trees and shrubs are the victims of diseases, poor fertility, climate extremes, incorrect soil moisture conditions, environmental pollution (air, soil or water), and physical injuries.
"Symptoms" are displayed on the plant as a result of a biotic or abiotic problem. It isn't possible to see the organism itself, but you can see the plant's response to the problem. For example, wilting leaves may be the result of a root rot fungus that is preventing the roots from taking up moisture. You see the symptom--wilting leaves--but not the fungus itself.
"Signs" are direct evidence of the cause of the disease. You may see mushrooms growing around the base of the plant. You see actual parts of the fungus--mushrooms--that is causing the root rot.
When assessing an unhealthy plant, look for any and all symptoms and signs that may be present. Thoroughly observe the leaves, stems, branches, trunk and, if possible, roots.
Consider the history of the plant, since often symptoms do not appear until years after the cause. For example, construction damage to a large tree's roots may not cause dieback or tree death for several years, as the tree tries to hang on and grow new roots.
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