What is the primary soil-inhabiting insect pest of turfgrass in Iowa?

White grubs are considered the primary soil-inhabiting insect pest of turfgrass in Iowa because they are the larval stage of various beetles, particularly the Japanese beetle and the masked chafers. These grubs live in the soil and feed on the roots of grasses, leading to significant damage to lawns and turf areas. Their feeding can cause patches of grass to wilt and die, making identification and management crucial for maintaining healthy turf.

In contrast, while cutworms are also damaging, they primarily impact seedlings and young plants above ground rather than being a soil-dwelling pest. Leafhoppers tend to feed on the above-ground parts of plants and are more associated with transmitting plant diseases instead of thriving exclusively in the soil. Chinch bugs, on the other hand, are not soil-inhabiting pests; they mostly feed on turfgrass leaves and do not have a larval stage that resides in the soil. Thus, the characteristics and behaviors of white grubs clearly establish them as the main concern for turfgrass health in this context.