Which two factors are most important in avoiding vapor drift?

The important factors in avoiding vapor drift include temperature and pesticide volatility. Temperature plays a critical role in the behavior of pesticides after application; higher temperatures can increase the volatility of certain pesticides, causing them to evaporate into the air more quickly. This can contribute to vapor drift, where pesticides spread beyond the intended treatment area, potentially affecting non-target organisms and disrupting local ecosystems.

Pesticide volatility refers to how readily a chemical vaporizes. Pesticides with high volatility can turn from liquid to gas at lower temperatures, leading to a higher risk of drift. Understanding these characteristics helps ensure that applications are made under suitable conditions that minimize the likelihood of unintended movement of the pesticide through the air.

While droplet size and wind speed are also important in the context of drift and spray applications, this question specifically highlights factors that relate to vapor drift rather than physical drift during application, making temperature and pesticide volatility the more relevant options.