What type of herbicide is associated with buggy-whipping and malformed brace roots on corn?

• A. Seedling growth inhibitors
• B. Photosynthesis inhibitors
• C. Growth regulator herbicides
• D. Amino acid synthesis inhibitors

Answer: (C)

The correct answer is associated with growth regulator herbicides, which are known to disrupt the normal growth patterns of plants, including corn. These herbicides, such as 2,4-D and dicamba, mimic natural plant hormones and can lead to abnormal growth responses.

When corn plants are exposed to growth regulator herbicides, they may exhibit symptoms like buggy-whipping, where new leaves appear deformed or elongated, and malformed brace roots, which can hinder the plant's stability and nutrient uptake. The presence of these growth regulators can disrupt the plant's hormonal balance, leading to these particular morphological abnormalities.

Other options represent different modes of action for herbicides. Seedling growth inhibitors generally target the embryonic growth phase of plants and wouldn’t typically cause the specific symptoms mentioned. Photosynthesis inhibitors work by blocking the process of photosynthesis but do not specifically cause buggy-whipping or root malformations. Amino acid synthesis inhibitors interfere with the production of essential amino acids but also do not directly lead to the symptomology associated with growth regulator herbicides. Thus, the connection between growth regulator herbicides and the specific plant deformities is the reason why this choice is correct.