The disease leads to severe losses if control measures are not undertaken. The trees are severely weakened. A severe infection can even lead to a crop failure. No flower buds will develop in the following year, and the wood may freeze during winter.
Leaf curl [Taphrina deformans]
Leaf curl - image 1
The fungus overwinters on bark or on bud scales. The spores are carried to new buds during spring rains. In the form of a thin germ tube, the fungus penetrates the leaf tissue, where it causes the characteristic deformation (Picture 1). The infection is weather-dependent. Temperatures below 19C and frequent rain during budding, the greater the incidence of the disease. The spores are formed in the whitish fuzz on the upper surface of the leaf. At the end of spring, these spores are discharged and then land on the shoots of the same or nearby trees. They germinate there and give rise to the overwintering form. The life cycle is thus completed.
Pattern of damage
Greenish-white or reddish colored, brittle lesions appear on the leaves soon after budding. The leaves curl up (Picture 1). A whitish fuzz can be found on the upper surfaces of infected leaves. These leaves dry up and then drop off. The fruits drop off as well.