• The crabapple tree brings with it the rewards of flowering blossoms in the spring and the promise of ornamental fruit in the fall. Gardeners tending to crabapple trees should be aware of potential diseases and preventative measures that can be used to avoid them. Understanding the potential conditions of the crabapple tree will aid in maintaining its health throughout all four seasons.
  
  

Apple Scab Disease

• Apple Scab disease is a condition of the crabapple tree whereby greenish brown moldy patches appear on the leaves and fruit of the tree. A fungal disease, Apple Scab is propagated in humid and wet conditions such as spring showers and standing water. It takes only 9 days for the spores of this fungus to germinate and infect a tree and many of the leaves and fruit will be lost prematurely as a result. The most practical measure for preventing Apple Scab is the diligent removal of fallen leaves from the base of the tree in order to prevent any disease living in dead leaves from spreading. There are also fungicide products that can be applied in the spring and summer to aid in disease prevention.
  
  

Fireblight

• Fireblight is a bacterial infection that causes the flowers and twigs of a crabapple tree to shrivel up and turn dark shades of brown and black, as if they had been burned. Severe oozing patches form on the branches of a tree during the end stages of Fireblight which can not only infect other plants but can also kill the tree. Crabapples are not the only trees susceptible, as rosebushes, apple tree and pear tree varieties can all become victims. The bacteria that causes Fireblight is transmitted by bugs, birds, rain runoff and gardeners who unknowingly spread the infection from one plant to another. The best prevention is to cut away infected areas of the tree, being careful to dispose of or sanitize everything that comes in contact with the infected limbs. There are bactericide garden products that can also help.
  
  

Frogeye Leaf Spot

• Frogeye Leaf Spot is a fungal disease appearing in crabapple tree leaves as brown spots with purple outlines. Symptoms of Frogeye usually appear after crabapple trees have blossomed. Mild forms of the disease lead to a mere discoloration of the leaves with no further symptoms. In more severe cases of the disease these brown spots continue to worsen into the summer leading to a premature loss of leaves. Spores that are released by the matured brown patches can spread to other plants through wind and rain runoff. While not lethal to the crabapple tree, Frogeye can discourage tree growth. Removing infected branches and implementing fungicide products can help eliminate the disease.