Correct Option: B. Corn rootworm Detailed Explanation: Why Corn Rootworm is the Correct Answer:

1. Identification of the Pest:
2. The corn rootworm (Diabrotica spp.) is a significant pest specifically associated with corn (Zea mays) crops. It is known for its larval stage, which primarily feeds on the roots of corn plants, but it can also cause damage to the stems and kernels.
3. Feeding Habits:
4. The larvae of corn rootworms feed on the roots of corn plants, which can lead to weakened plants that are more susceptible to lodging (falling over) and other stresses. Adult corn rootworms can also feed on the silks and kernels, leading to direct damage to the ears of corn.
5. Impact on Yield:
6. The damage caused by corn rootworms can significantly reduce corn yields. When the roots are damaged, the plant's ability to absorb water and nutrients is compromised, leading to stunted growth and lower overall productivity.
7. Lifecycle and Behavior:
8. Corn rootworms have a lifecycle that includes egg, larval, pupal, and adult stages. The larvae hatch from eggs laid in the soil and begin feeding on the roots shortly after. This lifecycle is closely tied to the corn growing season, making them particularly problematic for corn farmers.

Why the Other Options are Incorrect: A. Aphids: - Aphids are small sap-sucking insects that can affect a variety of crops, including corn. However, they primarily feed on the plant's sap and do not cause significant damage to the kernels or stems. Their impact is more related to the transmission of plant viruses and the production of honeydew, which can lead to sooty mold. B. Corn Rootworm: - As discussed, this is the correct answer due to its specific feeding habits and the significant damage it causes to corn crops. C. Whiteflies: - Whiteflies are another type of sap-sucking insect that can affect various crops, including vegetables and ornamentals. They do not typically feed on corn kernels or stems and are more associated with transmitting diseases and causing stress through sap feeding. D. Spider Mites: - Spider mites are tiny arachnids that can cause damage to many plants by feeding on the undersides of leaves. While they can lead to leaf discoloration and reduced photosynthesis, they do not directly feed on corn kernels or stems, making them less relevant to the question. Summary of Key Points:

• Corn rootworm is a major pest of corn, known for damaging roots, stems, and kernels.
• Aphids, whiteflies, and spider mites do not primarily target corn kernels or stems, making them less significant in this context.
• Understanding the specific feeding habits and lifecycle of pests is crucial for effective pest management in agriculture.
• Effective control measures for corn rootworms include crop rotation, resistant varieties, and integrated pest management strategies.

This thorough understanding of corn rootworms and their impact on corn crops is essential for anyone studying agricultural science, particularly in pest management and crop protection.