The term "canker" is used to describe a killed area or blister on the bark, a branch or the trunk of an infected tree. The canker-causing fungi commonly invade wounded or injured bark tissues to form a canker and subsequently produce reproductive structures called fruiting bodies. Dozens of species of fungi cause canker disease.
Preventing cankers means growing vigorous trees that can fight off the entrance of pathogens into the bark. Wounds are essential for most canker infections so avoid wounds, especially where active cankers are present. Plant your tree on a good site, use vigorous planting stock, fertilize trees to promote growth and control weeds for several years after planting. Landscape trees will benefit by deep watering or trickle irrigation, especially during dry summer months plus maintain good drainage.
Canker diseases can be controlled if diagnosed early. To control canker disease on trees, cut off the affected branch or limb. If a large canker is on the main trunk, the tree may need to be replaced. No effective chemicals are available to control the fungi that cause canker disease. Keep your tree healthy and take this test: Do you know how to keep your tree healthy? Take This Test.