Which of the following is an essential consideration when using ULV spraying equipment to obtain good results?

• A. Use only the largest droplet size to maximize coverage.
• B. Ignore label directions and safety precautions.
• C. Spray only when wind is high.
• D. Keep the ULV equipment well maintained and properly calibrated for the proper dose rate of insecticide and the optimum insecticide droplet size.

Answer: (D)

In ULV spraying, getting good results means precise control of both how much insecticide is released and the size of the droplets. That control comes from keeping the equipment well maintained and properly calibrated. When the machine is clean, wear parts are replaced, nozzles aren’t clogged, seals are sound, and the fan or pump operates as designed, the system delivers a stable, predictable output. Calibration links that output to a target dose and confirms the droplet size spectrum matches the label for the target pest and area. With accurate calibration, you’re more likely to achieve effective coverage of mosquitoes while minimizing drift and environmental impact.

The other ideas aren’t right because using the largest droplets can reduce overall coverage and alter deposition, ignoring label directions and safety is unsafe, and spraying in high winds increases drift and reduces effectiveness.