Which of the following stored product pests is known to attack whole grains?

Rice and granary weevils are known for their specific behavior and feeding habits that involve attacking whole grains. These pests are members of the beetle family and have adapted to live in stored grains, primarily attacking rice and wheat, but they can infest other types of whole grains as well. Their larvae develop within the grain kernels, leading to significant damage and contamination.

In contrast, corn earworms primarily attack corn plants and do not have the same focus on stored grains. Clothes moths are typically associated with natural fibers in textiles rather than grains, as they are known for damaging fabrics, especially wool and silk. House flies are not pests that infest stored products; rather, they are generalist pests that are primarily known for being nuisance pests around decaying organic matter and do not specifically target grains for infestation. Hence, the correct answer is based on the specific feeding and infestation behaviors of rice and granary weevils in relation to whole grains.