Why is it advised not to spray pesticides during the hottest part of the day?

Spraying pesticides during the hottest part of the day is primarily discouraged to reduce the risk of drift. When temperatures are high, the increased thermal energy can cause the pesticide particles to become lighter and more prone to being carried by the wind. This drift can lead to the pesticides being unintentionally applied to non-target areas, which can harm beneficial insects, plants, or even human populations nearby. Therefore, applying pesticides during cooler times, such as early morning or late evening, allows for better control over where the pesticide will land and minimizes adverse environmental impacts.

The other options are related to different factors but do not directly address the primary concern of drift. For instance, preventing evaporation is important, but it is not the primary reason for avoiding mid-day applications. Similarly, improving pesticide solubility and increasing microbial degradation pertain to different aspects of pesticide behavior but do not convey the immediate risks associated with drift during high-temperature conditions.