Fruit Tree Diseases in France: Powdery Mildew

Quick read / the essentials on powdery mildew on fruit trees

Powdery mildew, or "powdery mildew," is a fungal infection that affects several fruit species, including peach, apricot, apple, and plum. This fungus appears as a powdery white growth that colonizes leaves, young shoots, and sometimes fruit. It develops particularly during hot, dry periods with high nighttime humidity, leading to slowed growth, fruit deformation, and reduced yield.

At Arboriverse, a specialist wholesale supplier of fruit plants , we know that prevention is the main lever against powdery mildew. Choosing resistant varieties , particularly for apple and peach trees, helps reduce the susceptibility of orchards. Careful management of the orchard is essential: pruning must promote air circulation , thus limiting the humidity conducive to the disease. Balanced fertilization avoids excess nitrogen, which makes the tissues more vulnerable. Finally, watering at the base of the trees , without wetting the foliage, reduces the spread of the fungus.

In organic farming, applying baking soda as a cure and sulfur as a preventative is effective in limiting the growth of the fungus. Talc can also be used as a physical barrier to prevent spores from establishing. In conventional farming, systemic fungicides provide long-lasting protection when applied at the right time.

At Arboriverse, a specialist wholesale supplier of fruit plants , we offer plants tailored to the needs of growers, ensuring vigor and adaptation to local conditions. Buying peach, apricot, apple, and plum plants from a specialist is a guarantee for a more disease-resistant and productive orchard.

Powdery mildew on fruit trees: identification, prevention and control

Powdery mildew, also known as powdery mildew, is a fungal disease affecting many fruit tree species. This fungus thrives primarily in warm, dry conditions with high nighttime humidity. Effective disease management relies on preventative practices and appropriate treatments as soon as the first symptoms appear.

Fruit tree species concerned

Powdery mildew affects several fruit species, including apricot, peach, nectarine, apple, pear, almond, plum and cider apple.

Although some species such as cherry, quince, pomegranate, persimmon, nashi (Japanese pear), and medlar may occasionally be affected, powdery mildew is generally not a major disease for these trees. Susceptibility also varies among varieties within the same species.

Symptoms of the disease

Powdery mildew appears as a powdery white growth on different parts of the tree, earning it the nickname “powdery mildew.”

White, floury spots appear on the leaves, often accompanied by deformation and curling of the foliage. These changes can slow growth and reduce the tree's photosynthetic capacity.

On young shoots, the fungus forms a powdery coating, which weakens their development and can cause them to dry out prematurely.

On the buds, an early attack leads to a weakening of flowering and a reduction in fruit production potential.

Powdery mildew can cause whitish, corky spots on fruit, affecting its appearance and taste. In some cases, the fruit remains deformed and fails to ripen, making it impossible to sell.

Means of prevention

Prevention is essential to limit the development of powdery mildew in orchards.

Choosing resistant varieties is a first line of defense. Some apple and peach varieties are bred for their increased tolerance to the disease, thus reducing the need for phytosanitary interventions.

Proper ventilation of the orchard is essential to limit stagnant moisture and prevent the proliferation of fungus. Pruning should be carried out in such a way as to promote air circulation between the branches and to avoid overly dense foliage.

Appropriate cultural practices help limit the risk of infection. It is recommended to avoid excess nitrogen, which promotes rapid growth and leaves susceptible to disease. Watering the base of the trees, without wetting the foliage, also helps reduce the humidity conducive to the development of the fungus.

Regular monitoring of the orchard is essential to detect early symptoms and intervene quickly before powdery mildew spreads.

Means of control and treatments

When powdery mildew is detected, appropriate treatments must be implemented to limit its progression and protect the trees.

In organic farming, several natural solutions are available. Baking soda is an effective curative treatment that blocks the growth of the fungus. It should be applied as soon as the first symptoms appear to limit the spread of the disease.

Talc is used as a preventative treatment. It forms a physical barrier that prevents the growth of fungus and thus reduces the risk of infection.

Sulfur is one of the most commonly used treatments in organic farming against powdery mildew. It is applied in powder or liquid form and works by disrupting the fungus's metabolism. Its effectiveness is greatest in prevention or at the beginning of an infestation.

In conventional agriculture, the use of specific fungicides is recommended. Systemic fungicides are particularly effective because they penetrate the tree tissues and provide long-lasting protection against fungal attacks. However, it is essential to follow the dosages and manufacturers' recommendations to minimize environmental impacts and prevent the development of resistance.

Conditions favorable to the development of the disease

Powdery mildew thrives in specific climatic conditions. It develops primarily when temperatures are high during the day and humidity remains high at night. Unlike other fungi, it does not require the presence of free water to germinate, which explains its proliferation during dry periods.

A warm, dry spring followed by humid nights provides an ideal environment for the development of the disease. Arborists must therefore be particularly vigilant during these periods and intensify monitoring of their orchards.

Conclusion

Powdery mildew is a serious fungal disease that can affect many fruit tree species. Preventive measures are essential to limit its occurrence and reduce production losses.

Proper orchard management, combined with appropriate treatments in the event of infection, helps protect trees and ensure quality harvests. Regular monitoring and the adoption of appropriate cultural practices remain the best weapons for combating this disease and maintaining healthy orchards.

To summarize: how to protect your fruit trees against powdery mildew?

Powdery mildew is a disease that can seriously affect orchards, reducing tree growth and affecting fruit quality. Its prevention relies on careful orchard management, the selection of suitable varieties, and targeted treatments to limit its spread.

Arboriverse, a specialist wholesale supplier of fruit plants , supports arborists by offering resistant varieties selected for their vigor. Buying peach, apricot, apple and plum plants from specialized production helps limit susceptibility to diseases and optimize the productivity of the orchard.

Appropriate cultural management is essential to limit the risk of infection. Proper pruning , avoiding overly dense foliage, reduces stagnant moisture and slows the proliferation of the fungus. Balanced fertilization , without excess nitrogen, promotes controlled growth that is more resistant to infections. Irrigation must be controlled, favoring watering at the base of the trees , without splashing water on the foliage.

When the disease is present, it is important to act quickly with appropriate treatments. In organic farming, applying baking soda as a cure and sulfur as a preventative limit the growth of the fungus. Using talc as a physical barrier is also effective in preventing spores from establishing themselves. In conventional farming, systemic fungicides provide longer-lasting action when applied according to recommendations.

Careful monitoring and rapid intervention are essential to protect crops and ensure optimal yields. At Arboriverse, a specialist wholesale supplier of fruit plants , we provide professionals with robust and resistant plants , ensuring a healthy and productive orchard. Buying peach, apricot, apple and plum plants from a specialist allows you to invest in suitable varieties and optimize the resilience of crops against disease.