Which variable is NOT mentioned as affecting spray rate?

The variable that is considered not to affect spray rate in this context is ambient temperature. While other factors like nozzle flow rate, application speed, and pressure directly influence the rate at which pesticide is applied, ambient temperature primarily impacts the behavior of the pesticide in the environment rather than the mechanical aspects involved in the spraying process.

Nozzle flow rate determines how much liquid is released per unit time, which is a critical factor in calculating spray rate. Application speed affects how quickly the pesticide is distributed over an area, directly changing the amount applied per acre or per minute. Pressure influences the droplet size and distribution pattern, thus impacting the total amount of pesticide that effectively reaches the target area.

Although temperature can influence the viscosity of the pesticide solution or its evaporation rate, it does not change the rate at which the sprayer can deliver the product, making it less relevant in the context of adjusting or calculating spray rate. This distinction highlights the importance of focusing on mechanical dynamics and physical specifications of equipment when assessing spray rate effectiveness.