Mildews Continue to Afflict Vineyards. What Strategies Might a Vineyard Manager Employ to Reduce the Risk? Flashcards
What are the two main types of mildew affecting vineyards?
Powdery mildew (Erysiphe necator) and downy mildew (Plasmopara viticola).
How does site selection help reduce mildew risk?
Well-ventilated, sloped sites with good drainage reduce humidity and leaf wetness, decreasing mildew infection risk.
Why is north-south row orientation beneficial in vineyard design?
It ensures even sun exposure and better drying, reducing conditions favorable to mildew development.
How does rootstock selection indirectly affect mildew pressure?
Less vigorous rootstocks produce less dense canopies, improving airflow and lowering humidity within the vine.
How does leaf removal reduce mildew risk?
It exposes bunches to light and airflow, drying out moisture that fungi need to thrive—especially effective before véraison.
What is the benefit of shoot positioning in mildew control?
It keeps the canopy open, reduces shading, and prevents the formation of humid pockets.
How can cover crops both help and harm in mildew prevention?
Help: reduce soil splash of spores. Harm: if too tall or dense, they increase humidity. Must be well-managed.
What are the main fungicides used in organic viticulture?
Sulfur and copper-based sprays, though copper use is regulated due to environmental concerns.
Name two biological treatments used for mildew prevention.
Bacillus subtilis and Trichoderma spp.
How do disease forecasting models work? Give one example.
They use weather data to predict risk periods for infection. Example: Gubler-Thomas model (California).
What vineyard technologies are emerging to help manage mildew?
Drones for spray precision, remote sensing for canopy density, UV and ozonated water trials.
Why is staff training important in mildew prevention?
Early symptom recognition and understanding of infection triggers improve timely interventions.
What is the most effective overall strategy to manage mildew?
An integrated approach combining site design, canopy control, appropriate sprays, and innovation.
What are the main pillars to reduce mildew risk in vineyards?
1) Site and variety selection, 2) Canopy and vineyard management, 3) Chemical and biological protection, 4) Technological and cultural innovations.
What factors should be considered during site and variety selection to reduce mildew risk?
1) Well-ventilated, sloped sites with good drainage, 2) North-south row orientation for better airflow, 3) Disease-resistant varieties (e.g., Voltis, PIWIs), 4) Selecting clones with looser bunches, 5) Low-vigor rootstocks.
How can canopy and vineyard management help reduce mildew?
1) Leaf removal around bunches (before véraison), 2) Shoot positioning (e.g., VSP), 3) Regulated Deficit Irrigation (RDI) to control canopy growth, 4) Proper management of cover crops.
What role does canopy management play in controlling mildew?
It improves airflow and sunlight exposure, reducing humidity around the clusters, which limits mildew development.
What are the main chemical and biological protection methods for mildew?
1) Preventative fungicide spraying during key periods (e.g., flowering), 2) Rotation of fungicides to prevent resistance, 3) Organic options (sulfur, copper), 4) Biological treatments (e.g., Bacillus subtilis, Trichoderma), 5) Oils and potassium bicarbonate to suppress mildew.
How do fungicide rotations help in mildew control?
Rotating fungicides with different modes of action reduces the risk of mildew resistance.
What technological innovations can aid in mildew management?
1) Disease forecasting models (e.g., Gubler-Thomas), 2) Drones for precision spraying, 3) Remote sensing to monitor canopy health, 4) Trials on UV light and ozonated water.
Why is staff training important for mildew management?
Staff must recognize early symptoms of mildew and understand how weather conditions affect infection, enabling timely and effective action.
What is the main conclusion of the essay regarding mildew management?
No single solution. A successful strategy combines preventive vineyard planning, proper canopy management, smart fungicide/biological treatments, and embracing new technologies.
