Sampling plans are relatively well-defined and easy to understand for which pests?

• A. Corn borers and alfalfa weevils
• B. Spider mites
• C. Sunflower moths
• D. All of the above

Answer: (A)

Sampling plans work best when pest populations are easy to count and there are clear thresholds for action. Corn borers and alfalfa weevils have well-established scouting methods and consistent damage patterns, so extension resources provide straightforward steps and decision points. For field corn, you can use a standard sampling approach to look for signs of borers or exit holes and to estimate infestation levels, with thresholds tied to expected yield loss. In alfalfa, sampling often involves checking a set number of stems and counting larvae or signs of feeding, again with clear thresholds to guide treatment.

Spider mites, by contrast, can be unevenly distributed and their populations can change rapidly, which makes simple, universal sampling plans harder to apply. Sunflower moths present their own complexity because larvae develop inside seeds within the heads and there can be multiple generations, complicating how and when to sample and interpret results. Because of these factors, the most straightforward, well-defined sampling plans are for corn borers and alfalfa weevils.