My peach tree has developed wrinkly contorted puckered leaves that are turning yellow and red in those areas. What is that and what can I do?
That is peach leaf curl, and at this stage, nothing you can do. It will cause defoliation of those leaves and some fruit drop, but doesn’t kill the tree (collect and pitch fallen leaves and fruit). Use normal care tactics to keep the tree healthy. Spray with a fungicide in the fall (after most leaves have dropped) and or in the spring just as the buds begin to swell.