Ecological Agrotechnics as the Foundation of Disease Prevention
Practical agrotechnics under organic viticulture conditions differs fundamentally from the traditional approach to protecting grapevines against fungal diseases. Instead of regular applications of synthetic fungicides, it emphasizes prevention, plant vitality, appropriate cultivar selection, and targeted cultivation practices.
Grapevines are highly sensitive to fungal diseases, particularly downy mildew, powdery mildew, and botrytis. In conventional viticulture, it has become common practice to rely on chemical protection to secure yields. However, it is important to recognize that chemical plant protection products also burden the environment, disrupt soil microbiology, and may negatively affect human health.
Historical Experience with Resistant Hybrids
In the official grapevine assortment in Slovakia, cultivars of the species Vitis vinifera have long predominated. While valued for wine quality, these cultivars are generally susceptible to fungal diseases. In older vineyards, however, so-called direct-producing hybrids (e.g., Othello, Izabella, Delaware) can still occasionally be found. These originated from crosses between European grapevines and American species during the phylloxera crisis.
These interspecific hybrids represented a temporary solution to the phylloxera problem but were later excluded from winemaking practice due to technological and health concerns, likely related to the content of diglycosides. As technical varieties, they ceased to be used and survived only sporadically in private gardens.
Modern breeding has since produced a new generation of interspecific cultivars with significantly higher resistance to fungal diseases and improved sensory qualities. These modern resistant varieties represent an important tool in organic viticulture.
The Impact of Chemical Protection on Natural Plant Resistance
Long-term use of systemic fungicides can suppress the natural defense mechanisms of plants. While the product is active, the vine remains protected; however, once the active substance degrades and only residues remain in plant tissues, the vine - having a weakened immune system - may become even more susceptible to subsequent infections. The natural defense capacity of grapevines can be significantly strengthened through a combination of proper agrotechnical practices, balanced nutrition, and biological stimulants. The goal is not to fight the disease, but to create a plant and an environment in which pathogens have greater difficulty establishing themselves. Organic management therefore focuses on strengthening the natural vitality of grapevines rather than creating chemical dependency.
Prevention as the Basis of Organic Protection
Planting material quality: A healthy vineyard begins with high-quality planting material. Vines should be sourced from reliable suppliers who guarantee varietal authenticity and plant health.
Knowledge about cultivars: Each cultivar has specific traits - disease susceptibility, frost tolerance, growth habit, and site requirements. Choosing an unsuitable cultivar often leads to an increased need for interventions.
Growing experience: When selecting cultivars for specific conditions, it is advisable to consult experienced local growers or viticulture specialists.
Vine care: A high level of agrotechnical management is essential. Proper pruning and canopy management improve light penetration and air circulation, thereby reducing leaf wetness and disease pressure.
Basic vine training: The fruiting zone should be positioned more than 1 meter above the ground. This reduces contact with soil moisture and lowers the risk of secondary infections.
Alternative Preventive Measures in Organic Practice
1. Cow manure extract
A fermented extract from well-rotted cow manure can act as a biological stimulant and support microbial balance on leaf surfaces. It is applied preventively during the growing season.
2. Foliar application of microelements
Microelements applied in chelated form support plant metabolic processes and increase tissue resistance to infection.
3. Sulfur against powdery mildew
Contact products based on colloidal sulfur are a cornerstone of organic protection against powdery mildew. Key application times are before flowering and shortly after flowering. At temperatures above 30 °C, sulfur may become phytotoxic, so weather conditions must be monitored.
4. Copper against downy mildew
Contact copper-based products provide preventive protection against downy mildew and are mainly used in the second half of the growing season under humid conditions. In organic systems, application rates must respect limits due to the potential accumulation of copper in the soil.
Organic viticulture is not about completely eliminating protective measures but about changing the philosophy of cultivation. Proper cultivar selection, healthy planting material, balanced nutrition, well-aerated and properly managed canopies, and preventive strategies create a system in which grapevines are naturally more resilient and the need for chemical interventions is significantly reduced. Such an approach leads to long-term sustainable production of healthy grapes and a more environmentally friendly relationship with soil and surrounding ecosystems.
