Peach leaf curl is favoured by a cool and wet spring around budswell followed by warm, humid conditions, which bring about rapid growth.
Peach leaf curl
The optimum temperature for fungal growth is 20C to 26C.
Thorough control of this disease requires a timely pesticide application.
A number of other measures can be taken to make management more effective.
Where leaf curl has been a serious problem it is important to put more effort into maintaining tree vigour. Thin more fruit than usual, ensure adequate irrigation and apply extra nitrogen fertiliser.
See this article in Tree Fruit August 2019