Peach trees, native to Asia, bear fragrant flowers and delicious fruit. They're easy to tend, but there are some diseases to look out for. The most common diseases for peach trees are leaf curl—which causes a thinning of the leaves that eventually affect the fruit—and brown rot, which affects the fruit itself.
TIP: Our expert gardening advisor, Kathy Bosin adds, "Proper thinning can help promote general health of the tree and production of peaches. Trees should be thinned regularly, improving air circulation and allowing sunshine to reach inside the tree canopy."
How to Look for Disease
Begin by looking at the leaves. Do they look healthy and straight, or are they curling backwards? A backwards curling leaf may be a sign of leaf curl, caused by a fungus called Taphrina. Feel the texture of the leaves you suspect may be diseased. These leaves will be thick and flimsy, whereas healthy leaves are thin, strong, and shiny. The color of the leaves should be spring green if healthy. If infected, the leaves will often be yellowish or dark brown and begin falling off.
Next, consider the tree itself. Does is look thin? Are there fewer leaves than usual? Check the branches for discoloration. Darker branches that are enlarged are often a sign of Taphrina as well. If the fruit is red or covered in brown soft spots, this may also be signs of disease.
Brown rot, caused by the fungus Monilinia fructicola, causes the fruit to rot away while still on the tree. In its last stages the fruit is entirely brown and looks whithered and dried out. The fungus can live in many temperatures and climates, but it particularly loves moist climates. The rot can also turn flowers brown and cause new twigs to die off.
To prevent the spread, make sure to clear away affected fruit, twigs or flowers. Do not compost the remains, as the fungus spores can live in compost and spread to the rest of your garden. A fungicide can also stop the spread of the fungus. Good air circulation and a drier enviornment also helps prevent rot.
Peach scab is caused by a fungus called Cladosporium carpophilu. It is most often found in warm, moist and humid areas, such as in the South. However, it can affect peach trees worldwide. The fruit will often crack and rot within those cracks, without much affect to the taste of the fruit. However, scab makes it harder for the peach skins to slip off during the canning process.
To prevent scab, use a chemical or organic fungicide just as the blossoms fall of the trees and for the ensuing month. Pruning and cleaning up fallen fruit and leaves will also prevent the continued spread.
Powdery Mildew is caused by the fungus called Sphaerotheca pannosa and affects both garden plants and fruit trees. Leaves often fall off or develop abnormally, eventually growing a white fuzz. An entire harvest can be ruined by mildew if left unattended. Consider purchasing tree varieties that aren't susceptible to the disease. Fungicide and proper area maintenance are also good preventative practices.
Leaf curl is a fungal disease caused by Traphrina deofrmans. It causes defoliation and crop loss in practically every variety of peach tree. Fungicide application during the fall after most of the leaves have fallen or before budding in spring can stop the fungus.