What is the primary diet of billbug larvae?

Billbug larvae primarily feed on roots, making this choice correct. The larvae are known to damage turfgrass by burrowing into and consuming the root systems. This feeding behavior can disrupt the plant's ability to absorb water and nutrients, leading to weakened grass and potentially large areas of dead turf.

Foliage, while important to other forms of pest damage, is not the primary diet of billbug larvae, as their life cycle is focused on the root zone where they can sustain themselves and cause significant harm to the grass. Similarly, flowers and seeds are not part of the billbug larvae's diet, as they are more specialized in attacking the structural part of the plant where nutrient absorption occurs. Thus, understanding the feeding habits of billbug larvae emphasizes the importance of monitoring and managing root health in turf areas affected by these pests.