Peach trees are susceptible to several types of cankers, which are dead areas of bark caused by injuries or infections. To lessen the chance of infection, avoid injuring peach trees with lawn mowers, trimmers, or other instruments. Prune in late spring or early summer when pruning cuts heal faster. Plant peach trees in well-drained soil with a neutral pH, in a full-sun area with good air circulation. Regular irrigation and fertilization is essential to the health of peach trees.
The fungus Phomopsis amygdali, formerly Fusicoccum amygdali, causes cankers on peach trees in early summer. The brown, elongated, sunken cankers constrict infected limbs, which wilt and die. The disease also causes irregular or circular brown spots on infected leaves. Remove and destroy infected limbs and foliage to prevent the spread of the disease.
A fungicide approved for Fusicoccum cankers on peach trees can be applied following the manufacturer’s directions to prevent and control the disease.
Leucostoma cankers are also known as peach, perennial, Cytaspora or Valsa cankers. They are caused by the fungus Leucostoma persoonii and are one of the destructive diseases of peach trees. The initial symptom is an exudation of gum from the infected area, followed by a small canker.
As the inner bark tissue decays, the canker enlarges along the length of the affected limb or branch. Each year the infection spreads into the healthy callous tissue around the canker and eventually girdles the limbs or branches. Older trees slowly decline as individual branches die, while younger trees usually succumb faster.
No treatment exists for Leucostoma cankers. Prune and destroy infected limbs and branches. In severe cases, the whole tree may have to be removed and destroyed.
Prunus Stem Pitting
Tomato ringspot virus causes prunus stem pitting on peach trees. It is spread by dagger nematodes, or through using infected plant material for grafting and budding. Initially infected leaves turn yellow and may cup upward along the midribs. Then they turn reddish or purplish and drop off.
The bark and sapwood thickens and pits, elongated indentations or swellings appear in the wood. Infected trees produce many small fruits that ripen and drop prematurely.
No treatment exists for Prunus stem pitting. Remove and destroy infected trees.