Bubble on stone fruit
The stone bubble is a disease caused by a fungus called Taphrina deformans. This tiny mushroom overwinters on fruit trees, especially on the peach tree, hidden near the buds, or in the cracks of the bark. The development takes place mainly in cool and rainy periods, with temperatures below 18 ° C; in fact, this pathology occurs mainly in the regions of central and northern Italy, in the spring period. When the first buds blossom, the mushroom begins its development, and attacks the young leaves; the symptoms are clear and evident: the foliage appears red, or yellowish, with evident swellings similar to blisters, and thickened leaf blade, with a rigid consistency. The leaves fall within a few days, and the spores of the fungus, which manifest themselves as a whitish patina, move on the fruits, on the wood or on other leaves. The poor photosynthetic capacity of the affected leaves and the defoliation cause a strong deterioration of the plant; the affected fruits block their development and fall to the ground.
How do you eradicate
The mushroom that causes the bubble on the stone fruit can easily withstand the winter cold and mild spring temperatures; its development stops only when the climate becomes hot, with temperatures above 18-20 ° C, and dry climate. Therefore, it survives on plants throughout the year, waiting for the most favorable period for its development. Generally the treatments are preventive, so as to nip the fungus when it is still in the embryonic phase, or when it has not yet attacked the plants, but simply hides on the trunk or branches. The treatments are typically practiced in late autumn, and in late winter, before the buds swell. Some qualities of fruits tend to be attacked with greater ease by this problem, and the cool and humid climate favors the development of fungi: in these cases, treatments are practiced even when the buds begin to swell, but always before flowering.