Monilia is a fungal disease that affects cherry, peach, apricot, and plum trees.
It is caused by two different fungal species: Monilinia laxa, which attacks the whole plant and can develop even at low temperatures, causing serious damage at different stages of the season; and Monilinia fructigena, which mainly attacks fruit and thin branches and needs warmer temperatures.
It is a very harmful disease and difficult to eliminate, because the fungi remain on parts of the plant and on surrounding plants in the orchard even during winter, then spread spores as soon as the temperature rises slightly.