Final answer:
Yellow jacket infestations should be treated during the late afternoon or nighttime, as the insects are less active and more likely to be in the nest, reducing the risk of stings and increasing the effectiveness of the treatment.
Step-by-step explanation:
Yellow jacket infestations should be treated at times when the insects are less active to ensure the treatment is most effective and safe. The best time to address these infestations is during the late afternoon or dusk to dawn (nighttime). At these times, yellow jackets are less likely to be active and are typically inside their nests, which makes treatment more likely to reach the entire colony. Additionally, lower temperatures during these times of the day can inhibit their ability to quickly mobilize and become aggressive, reducing the risk of stings to the person carrying out the treatment.
In contrast, during midday when temperatures are warmer, yellow jackets are most active, and treating infestations can be riskier and less effective. Early in the morning is also not ideal as yellow jackets may just be starting their daily activities. Thus, the end of the day or nighttime hours are recommended for such pest control activities. This way, the application of insecticides or other treatments is less likely to provoke the colony, and more of the insects are affected as they return to their nest for the night.