Which of the following must be calibrated for effective pesticide application?

Calibration of application equipment is crucial for effective pesticide application because it ensures that the correct amount of pesticide is being applied to the target area. Proper calibration allows for the adjustment of spray pressure, flow rates, and application speed, ensuring that the pesticide is distributed evenly and at the correct dosage. This is vital not only for achieving the desired pest control efficacy but also for minimizing environmental impact and avoiding potential harm to non-target organisms.

In contrast, while pesticide labels provide important information about the product, including application rates and safety precautions, they do not require calibration. Protective equipment is essential for the safety of the applicator but does not influence the calibration process of how the pesticide is applied. Soil conditions are a factor that may affect pesticide effectiveness but do not necessitate calibration of application equipment. Therefore, focusing on calibrating application equipment is key to successful pesticide management practices.