Peach Leaf Curl

About 

Peach leaf curl is a fungal infection caused by the fungus Taphrina deformans. It is known to infect peach crops in the U.S. 

Biology 

Taphrina deformans starts by overwintering in bark or crevasses around tree buds. Once the temperature reaches around 50°F to 70°F and humidity levels are above 95%, the buds will start to swell as rainwater brings spores to the leaf buds. 

The fungus then manipulates the leaf-growing cells and causes them to grow the leaves rapidly to release the mature spores.  

Because the leaves are forced to grow rapidly, they begin to form a warty texture with thickened areas that give the leaf a curled appearance. 

Eventually, the thick parts of the leaves change to a yellow or gray color before causing the leaves to droop. 

Preferred Host 

Peach leaf curl mainly affects peaches but is known to infect nectarines and ornamental crops. 

What to Look Out For 

Watch for blistered-looking reddish- or purple-colored leaves that are curled up and distorted. The thickened areas of the leaves will eventually turn a yellow or gray color.  

Though rare, infections on the fruit can occur. This makes the fruit look corky and cracked. Fruit that grows on these trees can become infected and typically fall off the tree before they ripen.  

Symptoms are most noticeable two weeks after the leaves begin to bud.  

Control 

Peach leaf curl is easy to control. The best way to get rid of the fungus is preventative care during the fall and winter months, as the spores are the most vulnerable.  

Due to the leaves acting as a protector for the buds containing spores, treating the fungus after symptoms show themselves is useless. Growers must wait until the fall to start treatment with fungicide.