Spring Tree and Shrub Diseases

Spring Tree and Shrub Diseases

During the spring, there are several tree and shrub diseases that can attack your trees.  Would you recognize a disease on a tree?  We will identify some of the common diseases and how to treat them.  It is important to remove the infestation as soon as possible to prevent the illness from spreading to other trees or shrubs.


Leaf Spot 

Leaf spot diseases reduce the ability of trees and shrubs to perform photosynthesis, which is how a plant makes its food.  Most leaf spot diseases are a result of infection by pathogenic fungi.  Once it is in the leaf, it will destroy the leaf tissue as it continues to grow.  The dead areas of the leaf are brown, tan, black, or reddish in color.   Most leaf spot diseases won’t harm a tree or shrub unless they are already stressed.  Raking and removing old leaves under the tree will reduce the number of fungal spores available to infect developing leaves in the spring.  Copper or neem oil fungicide can be applied at the time leaves start to bud, and again seven to fourteen days later.  It should be used as a protectant to prevent leaf spot.

Root Rot 

Root rot attacks the roots of trees growing in wet or damp soil.  Signs of root rot are wilted leaves, early leaf drop, poor growth, branch dieback, cankers, and thinning of the canopy.  It is caused by poorly drained or overwatered soil that prevents the roots from absorbing all the oxygen needed to live. Digging carefully to look for decaying roots is the best way to determine if the tree has root rot. Pruning out the infected roots is possible if the disease is in a small area. If the disease is significant, the tree should be removed to prevent it from spreading to other healthy trees. Systemic fungicides should be applied to the affected soil after the tree has been removed.


Anthracnose is a fungal disease that occurs in the late spring and early summer. It infects many deciduous and evergreen trees and shrubs, as well as vegetables, fruits, and grass. It appears as small lesions or spots that are tan, black, or reddish brown. Dark, sunken lesions may be found on stems, flowers, and fruits also. Although it does not harm the tree, it diminishes the curb appeal of the tree. Proper pruning to improve air circulation within the crown can prevent Anthracnose from spreading to other trees. Root feeding will help the tree combat the disease. Copper based fungicides can be used for treatment.

Rust Diseases 

Rust diseases are fungi that attack leaves, stems, tender shoots, and fruits. Plant deformities, growth retardation, and small orange/brown spores on the underside of leaves are signs of the disease. Immediately remove and burn all infected leaves to prevent the disease from spreading. Wash all tools with bleach solution to ensure that the spores are dead. Good soil drainage, careful watering, and cleaning tools will minimize problems. Fungicides with myclobutanil mancozeb chlorothalonil as the active ingredient can be used for treatment.

Needle Blight 

Needle blight is a fungal infection that affects new needle growth in trees and shrubs. It causes needle loss and can lead to branch death. The infection starts on the inner and lower branches. Early symptoms are deep green bands and yellow and brown spots on needles. A copper fungicide should be applied in the early spring to protect the previous year’s needles and again after the new needles appear. This should be repeated every year until all symptoms of the disease have disappeared.

Fungal tree and shrub diseases are hard to treat successfully. Prevention and early detection is the best way to ensure your plants stay healthy. Call Integrity Tree Care today for help determining if your tree or shrub needs to be removed.

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