While peaches can be a sweet summertime treat, if trees are impacted by twig dieback, that can leave a sour taste in producers’ mouths.
Plant diseases cause the twigs, branches and shoots of a peach tree to die. Alabama Cooperative Extension System Plant Pathologist Ed Sikora offers tips about what causes twig dieback, its symptoms and how to manage the disorder in peach trees.
Why Does it Happen?
Either bacterial blight disease or blossom blight disease lead to twig dieback. They are not uncommon to producers who contend with these diseases every spring. Bacterial blight is a bacterial disease that can cause dieback of twigs. Also known as brown rot, blossom blight – caused by a fungal pathogen – is a fruit tree disease that can also cause twig dieback in the spring, as well as fruit rot later in the production season.
Infected leaves can dry up and cling to their sticky branches. Cankers can also form at the base of the leaf buds and flowers. Especially in the spring, gummy sap can often be found exuding from these cankers.
During wet weather, brown-to gray spores of blossom blight can appear on dead flowers, indicating the fungal disease is the cause and not bacterial blight. If these spores are lacking, however, the Auburn University plant diagnostic lab can confirm which disease is the culprit.
According to Sikora, trees that are growing under stressful conditions are more susceptible to both diseases.
If weather is cool and wet, bacterial blight thrives. Blossom blight is associated more with warm, moist weather.
The first step in management of twig dieback is removing infected twigs from infected trees. Sikora advises pruning out affected tissue during dry weather to avoid the spread of bacterial blight, blossom blight or other pathogens.
It’s also important to disinfect pruners between trees. Soak the pruners in a 70% alcohol solution or a 10% bleach solution.
Later in the season, untreated blossom blight can lead to fruit rot, also known as brown rot. Once this occurs, it is crucial to remove and destroy all the affected fruit from the ground. This will reduce the spread of the pathogen.
“If affected fruit remains on the ground, fungal spores produced on the fruit surface can spread to healthy fruit in the tree,” Sikora said.
For more information, see the Alabama Extension content piece Causes of Twig Dieback in Peach Trees at www.aces.edu. People can also contact the Extension commercial horticulture agent that serves their area.