What causes a purple spot on nectarine fruit to shrivel and look like a prune? Every nectarine on the tree had this problem.
The Gardener’s Answer
Hello, Jim: Nectarines (Prunus persica nucipersica) are a delicious treat in the summertime, but they are not a low-maintenance fruit tree and they certainly have their share of insect and disease problems. There are varieties that are less susceptible than others but for the most part they are not the best choice for a minimal pesticide garden. They require a regular spray and fertilization schedule as well as annual pruning. There are way too many insect and disease problems to mention, but from what you have described it is not an insect problem. There are many bacterial/fungal problems associated with nectarines, including brown rot, scab, and bacterial spot, all of which could be possibilities. Without being able to see your tree it sounds like brown rot may be the problem. This fungus overwinters on mummified fruit that is left on the tree or on the ground. Did you notice any fruit last season that looked more like a prune instead of a nectarine? Good air circulation is essential for these fruit trees, and proper pruning will increase air movement and prevent future problems. In some cases the problem is first noticed on the foliage. For a positive diagnosis you should take a sample of the fruit as well as the foliage to your County Cooperative Extension Service. The agriculture/horticulture agent(s) will be able to look at your sample and give you a definitive answer. They also have the ability to send it off to have analyzed if necessary. The Muhlenberg County Web site is: http://ces.ca.uky.edu/muhlenberg;
the phone number is (270) 338-3124. For now you will want to remove and destroy all infected fruit both on the tree as well as the fruit that has already fallen.