How often should I spray my vineyard?

Spray intervals depend on disease pressure, product type, weather conditions, and growth stage. Typical intervals range from 7-10 days during high-pressure periods (pre-bloom through veraison) to 14-21 days during lower risk times. Contact fungicides generally require shorter intervals than systemic products. Always follow label directions for application timing.

Why is product rotation important?

Rotating between different fungicide modes of action (FRAC groups) is critical to prevent pathogen resistance. Using the same mode of action repeatedly selects for resistant populations, reducing product efficacy. A good rotation program alternates between at least 2-3 different FRAC groups throughout the season.

When should the first spray application occur?

The first fungicide application typically occurs at 3-6 inch shoot growth for powdery mildew programs, or when weather conditions favor disease. For downy mildew, the first spray is often timed to pre-bloom. Timing varies by region, variety, and disease history. Consult your PCA for site-specific recommendations.

How do I adjust spray intervals for weather?

Shorten intervals during wet, warm, or humid conditions that favor disease. Lengthen intervals during dry, cool conditions with low disease pressure. After significant rain events (0.5 inch or more), consider reapplying contact materials. Systemic products provide longer protection but should still be reapplied if there is significant vine growth.

Spray Schedule Calendar Builder

The Spray Schedule Calendar Builder helps you create a structured spray program for the growing season. Enter your first spray date, select a spray interval (7, 10, 14, or 21 days), specify the number of applications, and add product rotation details. The tool generates a complete calendar with spray dates, product assignments, and PHI windows to help you plan ahead and maintain consistent coverage.

Schedule Parameters

First Spray Date

Spray Interval (days)

Number of Applications

PHI for Calendar Markers (days)

Product Rotation

Product 1

FRAC

Product 2

FRAC

Important Safety Disclaimer

This tool is for informational and planning purposes only. Always read and follow the complete product label before any pesticide application. The label is a legal document and takes precedence over any calculator output. Consult a licensed Pest Control Advisor (PCA) for site-specific recommendations. VitiScribe is not responsible for decisions made based on this tool.

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