ASCI (a) clavate to cylindrical, with rounded or flattened top, naked, hyaline, 17-56 x 7-15 µm, usually with 8 ascospores, formed directly under the cuticule of the under leaf surface. The ascospores occasionally bud inside and outside the ascus to produce blastospores, which may also bud to form secondary blastospores. Infected leaf areas turn reddish and become thickened, swollen, distorted, and curled downward and inward when the underlying layers of asci mature. Finally, the leaves brown when colonized by saprotrophic fungi and fall.

Deformations of infected leaves of Prunus persica			Asci with ascospores

ASCOSPORES (as) subglobose to cylindrical, 3-7 µm diam.

NOTES. Taphrina deformans causes leaf curl of P. vulgaris (Agrios 1988). This is the most serious disease of peach (Smith et al. 1988). Later, the fungus initiates defoliation, which may lead to small fruit or fruit drop.

Taphrina deformans has a mycelial parasitic phase and yeast-like epiphytic phase (Smith et al. 1988).

The hyperplasia and hypertrophy of infected tissues result from the growth of an intercellular mycelium produced by budded blastospores.

How T. deformans overwinters is not fully recognized (Smith et al. 1988). It seems that T. deformans survives as the epiphytic yeast-like phase formed from ascospores. The ascospores may easily persist between the bud scales of the host. As soon as the buds burst, the fungus starts to develop.

REFERENCE

Agrios G. N. 1988. Plant pathology, 3rd edition, Academic Press, INC. San Diego, New York, Berkeley, Boston, London, Sydney, Tokyo, Toronto.

Smith I. M., Dunez J., Lelliott R. A., Phillips D. H., Archer S. A. 1988. European handbook of plant diseases. Blackwell Scientific Publications.