Responsible Spray Practices

Pesticide and fungicide applications play a role in integrated pest management (IPM), but when and how you spray can make all the difference—for your vines, your crew, your neighbors, and the surrounding ecosystem. With tighter regulations, climate variability, and increased community awareness, it’s critical that growers approach each spray event with intention, precision, and care.
Below is a framework for science-based, sustainable decision-making around pesticide applications. These principles help ensure each application is safe, compliant, and effective.

1. Pest Identification

• Clearly define the target pest or disease before applying anything
• Confirm whether the pest population has reached an economic threshold or poses a risk of unacceptable damage if left untreated
• Avoid prophylactic or calendar-based applications unless supported by environmental modeling (e.g., powdery mildew risk indexes)

2. Information and Professional Guidance

• Secure a licensed Pest Control Advisor (PCA) recommendation when required by law
• Review the product label and SDS (Safety Data Sheet) thoroughly, and ensure the product is registered for use on grapes and appropriate for the stage of vine growth
• Evaluate all environmental factors—temperature, humidity, wind speed, and inversion risk—to plan safe and effective application timing
• Consider whether a different time of day or weather window would minimize drift and maximize efficacy

3. Sustainability and Community Consideration

• Choose products and practices with low environmental impact, such as reduced-risk or OMRI-listed materials when possible
• Evaluate whether the application could affect nearby pollinators, wildlife, or waterways
• Ask: Is this treatment necessary? Could cultural practices (like canopy management) help reduce pest pressure instead?

4. Weather and Site Conditions

• Assess real-time weather conditions before and during application—wind speed, direction, temperature, and humidity can all affect drift and absorption
• Ensure mixing and loading areas are:
  • Away from wellheads or sensitive waterways
  • Equipped with backflow prevention and secondary containment where required

5. Application Equipment

• Calibrate sprayers to match vine canopy density and ensure even coverage per label recommendations
• Inspect equipment regularly for wear, leaks, or malfunction, and replace worn nozzles or filters
• Match equipment to site topography (e.g., hillside sprayers for steep blocks)
• Have spill kits, eyewash stations, and first aid supplies on-site and accessible during mixing and application

6. Employee Training & Safety

• Confirm that employees:
  • Can identify target pests and diseases
  • Know emergency contacts and response protocols
  • Have received required pesticide handler training, including PPE use, mixing procedures, and container disposal
• Make sure PPE (gloves, goggles, coveralls, respirators) is available and cleaned or disposed of per label requirements
• Review Re-Entry Intervals (REIs) and ensure signage and access control are in place post-application

​7. Communication

• Notify surrounding neighbors, schools, or nearby businesses when spraying near sensitive areas or if label or regulation requires it (read NVG's Vineyard Practices for Being a Good Neighbor)
• Check in with the Napa County Ag Commissioner’s office about any registered apiaries in the area, and avoid bee-toxic products or time applications to minimize exposure
• Clearly communicate with on-site employees and anyone who might be present during or after the application

8. Monitoring and Follow-Up

• After the spray, assess whether the application achieved desired control. If not, review materials and methods to adjust for next time
• Maintain detailed spray records, including weather conditions, materials used, block location, and operator details
• Continue to monitor for resistance development or secondary pest outbreaks, and adjust your IPM program accordingly

Key Takeaways: 

• Every spray counts: Treat each application as a high-stakes decision with environmental, legal, and human health impacts
• Preparation prevents problems: Calibrated equipment, trained teams, and thorough recordkeeping are essential for safe and effective applications
• Community matters: Responsible spraying extends beyond the vineyard—engage your neighbors, protect pollinators, and comply with notification laws