Peach trees are usually unaffected by pests or diseases in northern areas, the occasional exception being peach leaf curl. PLC is not a fatal problem but it does need to be controlled if you get hit with it. Look for crinkled or puckered foliage in spring. Remove affected leaves and compost them. A good preventative is to spray the dormant trees with copper in the fall and again in the spring before bud break (See page 63). Do NOT spray during the growing season as it will cause all the leaves to drop.