Answer: Foliage diseases of Madrone come in many forms and species. The fungi that cause leaf spots are not a serious threat to the tree unless repeated defoliation occurs. Madrone leaves are primary targets due to their high concentration of sugars. Most of our foliar fungi are more successful at attacking old leaves rather than new ones. The new foliage on the Madrone is rarely infected until fall. These fungal diseases intensify during periods of warm, wet weather. In some years, most of the foliage can be lost due to heavy fungal infections, but usually new leaves will replace this lost foliage in the summer. The good news is that foliar disease of the Madrone is not considered to be a major factor in their decline. There are no chemical sprays that are completely effective, so your best course of action is to rake the fallen leaves and remove them from the garden.
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