Which statement describes the timing to treat yellowjacket nests?

• A. Spring, day
• B. Fall, night
• C. Summer, morning
• D. Spring, night

Answer: (D)

Treat yellowjacket nests when the colony is least active and easiest to reach. In spring, the nest is small and the colony is just forming, so a single treatment can impact a larger portion of the population. Doing it at night adds another safety advantage: most workers are inside the nest and not patrolling or foraging, which reduces the chance of stings for the technician and allows the pesticide to contact more of the colony. During the day in warmer months, workers are out foraging and defending the nest, making treatment riskier and often less effective. That combination—spring with nighttime application—offers better control with lower risk.