The spots are brown, squishy and may get covered in a grayish mold as spores present. Additionally, as the season progresses stone fruit trees may show further signs of infection and damage as they begin to defoliate and gray spores and clumps appear on the flowers. These masses of gray material are spores. Along with the spread of spores, peach and nectarine trees may develop sunken lesions on the fruit tree bark, trunk and twigs. Extensive twig die-off may occur as the fungal infection becomes more severe, and as the growing season lengthens the lesions may begin to ooze a sticky, oozy material.
Spores emerge in the spring after over wintering in lesions and rotted fruit.
The rotted fruit which has overwintered is known as a mummy in the singular form. Clusters of rotted stone fruites are known as mummies. The spores are either splashed through rain and water or even wind that blows them from the infected mummies onto healthy peach and nectarine tree parts. Additionally, ooze from the lesions will begin seeping again once spring temperatures heat up and this infected fungal sap can spread onto previously healthy sections of the tree. The brown rot disease spreads especially quickly in moist, damp and warm temperatures and is easily splashed about as spores and sap during periods of heavy rainfall.