Dedicated to Tree Preservation in the Urban Forest

Leaf Diseases

 

Apple scab, Ink spot, Ash Yellows

                                                                                              

Various leaf diseases occur in Colorado.  Mechanical and cultural practices are best to help control disease.  Racking up diseased leaf litter in the spring and fall will help interrupt disease life cycles eliminating or reducing disease spores from reinfecting leaves.  Standing water on leaf surfaces should be keep to a minimum when possible.  Keeping humidity low by crown thinning and proper planting intervals will also help prevent disease.  Fungicide applications may also help to control various disease outbreaks.

 

Fire blight

 

Host: apple, pear, quince, crab- apple other various species

 

Fire blight is a bacterial disease that can cause severe damage and possible death in infected trees.  Fire blight can occur in twigs and limbs and even the trunk of the tree appearing like burnt twigs.  Twigs that are infested usually curl.  Leaves then dry out but remain attached to the twig.  Diseased portions of the tree are usually discolored and shrunken.  Planting resistant varieties and proper pruning will help reduce spread of the disease.  Pruning when weather is not cool and damp , sanitary maintenance practices like fall leaf clean up, and spray controls can help minimize bacterial spread.  Leaves should not be composted or stored on site.

 

 

 

 

 

            

Leaf Diseases ● Fire blight