The Insidious Leaf Curl of Peaches

Peach leaf curl is a fungal disease affecting mainly peaches, but also almonds and peach-almond hybrids. It is caused by the fungus Taphrina deformans. This disease attacks trees almost every year and significantly weakens them, making protection very important.

Infection can be prevented or limited through chemical protection, but it's essential to know when is the right time and which products to use.

Symptoms and Consequences of Peach Leaf Curl Infection

The most obvious symptoms can be observed on the leaves. First, yellowish, later red blisters appear on them, the leaves curl and become deformed. A large portion of flowers falls off, fruits are smaller, sometimes they also have spots on the surface or crack. In summer, infected leaves fall off and new ones sprout, but this process significantly weakens the tree, which affects both the fruits and frost resistance and the ability to resist other diseases.

Sometimes peach leaf curl can be confused with aphid infestation. Some aphid species also cause red blisters through their feeding. However, we can distinguish them by examining the underside of the leaf - in case of fungus, it will be covered with a fine white coating, in case of aphid infestation we will find either live individuals or sticky spots on the leaf surface.

Life Cycle of Taphrina deformans

The fungus spreads through spores. These survive unfavorable periods and enable reproduction. After spore germination, mycelium forms inside plant tissues and at this stage it's not possible to damage the fungus with sprays. Taphrina begins to germinate and grow already at seven degrees above zero, therefore the protection period against it takes place mainly in late autumn and early spring. It thrives in wet weather, so infection tends to be greater during rainy springs. Spores overwinter on fallen leaves, trunk, shoots and on bud scales.

Protection Against Peach Leaf Curl

Preventive protection primarily involves selecting more resistant varieties of peaches and proper pruning, which allows quick drying of leaves and branches and thus prevents disease development. Through proper fertilization and sufficient watering, we can improve the plant's condition and thus its defense capability. However, if it is already infected, it cannot defend itself. If infection occurs regularly, it's necessary to start spraying as well.

Chemical protection spraying can be carried out at any time from leaf fall to the terminal bud burst phase (when green stripes appear on the buds). It is important to have frost-free weather without precipitation during application and for several days afterwards. The spray should be repeated once or twice, but with at least a two-week interval. It is advisable to alternate products to prevent the fungus from developing resistance. Suitable products include Dithane, Champion, Delan, Kuprikol, Korzar, Optikombi or Kocide.

When spraying, ensure that the entire trunk and branches are treated. A common mistake is thinking that the fungus only overwinters in leaf buds. However, spores are scattered across all parts of the tree.