When are large white grubs most likely found near the soil surface?

• A. Fall
• B. Early Spring
• C. Summer
• D. Winter

Answer: (A)

Seasonal movement of grubs is driven by temperature and their life cycle. Large white grubs, the larvae of scarab beetles, feed on turf roots but move through the soil as they develop. As fall arrives and soil temps drop, they begin migrating upward toward the surface to overwinter. That shift brings many grubs into the upper soil layer, making them most likely to be found near the soil surface in fall. This timing also explains why fall is the best period to scout for them in the top 6 inches of soil. In contrast, during hot midsummer they tend to be deeper to avoid heat, and in winter the surface is often too cold or inactive for reliable detection, with spring showing movement up again but not as consistently near the surface as in fall.