Spraying nothing is free, easy on the environment and requires no effort. Consider leaf diseases of large trees. Many different species of fungi can infect and cause brown spots on the leaves of shade trees such as oak, maple and ash. Such problems often are referred to as leaf blight or anthracnose diseases. Their occurrence can be especially common after wet-weather periods in the spring.
Homeowners get worried when some of the affected leaves fall to the ground prematurely.
Fortunately, established trees have plenty of leaves. Scattered brown spots on the leaves and the early loss of a portion of the leaves is usually just a minor annoyance to the tree. The warmer and drier conditions of summer are not as favorable for these fungi and disease development slows down. Later flushes of growth often mask early loss of leaves. Fungicides can protect trees from infection by these leaf spot fungi.