Peach leaf curl is a fungus disease that, under the right conditions, can cause severe early defoliation and crop loss on nearly all peach and nectarine cultivars. As the name of the disease implies, the most common and striking symptom of leaf curl occurs on the foliage. Infected leaves are severely deformed and often display a variety of colors ranging from light green and yellow to shades of red and purple. In most areas leaf curl can be controlled with one well-timed fungicide application
, either in the autumn after 90% of the leaves have fallen, or in the spring before bud swell.