Your friends are busy boasting about their homegrown strawberries and melons, but you have much bigger plans. You want to grow nut trees. It’s a big commitment, but it can yield a big reward if you have the space and time to dedicate to nut growing. One of the many things you’ll want to learn more about is diseases that affect nut trees. Treating a sick nut tree early is important to preserving all your hard work and protecting your harvest! Read on for information on what diseases affect nut trees.
Common Nut Tree Diseases
Although we don’t have enough space to cover all possible nut tree diseases and nut tree disease symptoms, we’ve picked out some common nut tree diseases to highlight to get you started on your nut tree care adventure. As your trees grow and mature, keep your eyes open for these common problems:
Anthracnose. Wet weather in late spring and early summer make anthracnose better able to survive on nut trees. When the fungus infects leaves, it can cause them to drop prematurely, resulting in tree defoliation, or pinkish lesions may form on the nuts themselves. You can choose to replace your trees with anthracnose resistant varieties or you can try to save the trees you have with sprays of fungicides like mancozeb or benomyl.
Sanitation is really important for preventing reinfection, as is establishing a preventative spray program. Spray with a fungicide when the leaves just start to unfold, then four more times at two week intervals.
Leaf spots. Various leaf spot diseases occur in nut trees, resulting in decreased ability to photosynthesize and increased stress. Leaf spots might be yellow, brown or black, the size of the head of a pin or of a coin, but in nut trees they can all significantly influence your yield.
When you notice leaf spots, start a spray program using copper fungicide (unless fruit are still very young, in which case a phytotoxic reaction is possible). Ideally, you’ll begin spraying when the leaves unfold and spray monthly until mid-summer.
Oak root fungus. When small gold-colored mushrooms appear at the base of your nut tree, it’s not a good sign. Your tree may be suffering from oak root fungus, also known as honey mushroom rot. Unfortunately, once you see the mushrooms, it’s years too late to prevent the infection or reverse it. Infected trees will show an overall decline, may experience dieback and if you peel the bark back, you’ll find the signature white mycelial fans that are the hallmark of the disease.
There’s no cure and no long-term treatment. The best you can do is remove the tree and try to prevent the fungus from spreading. Make sure all the parts of the tree have been cleaned up, including chunks of root that might be buried.