Cedar-apple rust is a fungus that emerges in the early Spring season. This fungus must have both the cedar and apple tree within range for the fungus to develop. Fungal spores are carried by the wind, and can spread the disease for many miles. In this case, every cedar tree in the customer’s landscape has been effected. I took a walk deep into the woods behind the property, and every cedar I checked also was covered with rust. Cedar-apple rust is a natural occurance, and rarely causes stress or decline to the “natural” cedars in the landscape. Ornamental cedars, planted by the homeowner, can be damaged if rust is allowed to take hold. Fungicides can be applied to the trees to prevent contamination. Trying to prevent cedar-apple rust on your natural cedars will be an uphill battle. Especially if you have had outbreaks in previous seasons.
