Leaf curl (Taphrina deformans): identification and ecological, chemical and biological treatments

Taphrina deformans is an ascomycete fungus responsible for the disease known as peach leaf curl, one of the most damaging diseases affecting stone fruit trees, especially peach, nectarine, flat peach and, to a lesser extent, almond trees and other Prunus species. This pathogen mainly attacks young leaves, tender shoots and, during favorable seasons, even fruits. The fungus survives as mycelium or spores on the surface of bark, buds and scales throughout winter, waiting for suitable humidity and cool temperatures to infect plant tissues during bud break.

The disease causes severe foliage deformities that reduce photosynthetic capacity and weaken the plant, potentially compromising annual production. Repeated infections year after year lead to significant vigor loss, premature leaf drop, secondary sprouting and increased susceptibility to frost damage or sunburn. Management requires special attention to preventive winter treatments or applications before bud break, since the fungus only infects tissues during the initial growth stage.

Symptoms and damage caused by leaf curl

• Curled, thickened and deformed leaves with very characteristic swellings.
• Color changes to reddish, yellowish or purple tones on young leaves.
• Fleshy or thickened texture of affected leaf tissues.
• Premature leaf drop, which may leave the tree partially defoliated.
• Weak secondary sprouting after defoliation.
• Damage to young shoots, which may become deformed or dry out.
• Occasional fruit damage with surface deformities and rough appearance.
• Reduced overall vigor and lower production when infections are severe.