Bright orange balls of gelatin are clinging to some of the trees on the farm. Two-inch tentacles sprout from the spheres and shake in the breeze. Is this a case of alien contact? No, it’s just a fungal invasion. Those orange growths are a type of fungus called cedar-apple rust. The bane of apple farmers across North America, cedar apple rust needs two hosts to complete its life cycle: apple trees and eastern red cedars. Last summer, spores drifting on the breeze landed on the branches of cedar trees. After sucking nutrients from the host tree, the spores turned into little bean-shaped growths (also called galls). With spring’s warm rains, tentacles began poking out of the galls, forming gooey horns.
Now the fungus will release new spores into that slime, and the breeze will carry the spores to neighboring trees (up to 2 miles away!) as the fungus dries. If the spores land on an apple tree, the fungus produces bright orange “rusty” spots on the leaves. Throughout the summer the rust spots will take nutrients from the leaf, and taking food away from the developing apples. Apple trees infected with cedar apple rust will produce smaller fruit and fewer apples than healthier trees. So while the fungus doesn’t kill the trees, it does hurt the apple growers! One of the best ways to combat the fungus is to remove one of the host trees – this is why you will almost never see a cedar tree at an apple orchard!
At the end of the summer, long spines developing on the apple trees will release spores back onto the wind. If these spores find a cedar tree, the whole process will start again.
While we don’t sell apples at Jones Family Farms, we do have several apple trees on the property from the days when the farm was a livestock and dairy operation. Many of the older homesteads in New England still have apple trees that were planted when families provided much of their own food. So if you have an apple tree in your yard, keep an eye out for cedar-apple rust this year!