Illinois Field Crop Applicators Practice Test

What type of herbicide application has a relationship with low crop residue cover?

1. Higher rate application

2. Lower rate application

3. Even application

4. Infrequent application

The correct answer is: Higher rate application

The relationship between herbicide application and low crop residue cover is significant because lower crop residue can lead to increased herbicide efficacy. When crop residue cover is low, there is potentially less interference from the residue that could shield weeds or reduce herbicide contact with the soil surface. Higher rate applications can compensate for any reduced effectiveness caused by environmental conditions or weed pressure, ensuring that sufficient active ingredient reaches the target weeds. This is particularly important in scenarios like no-till or reduced-till farming systems, where crop residue can inhibit herbicide effectiveness. In contrast, options like lower rate applications may not provide enough herbicide concentration to control weeds effectively in areas where crop residue is low. Even application refers to the distribution of the herbicide across the field, which is crucial but does not directly correlate with residue levels. Infrequent application might imply that herbicides are not applied regularly, which could lead to missed weed control opportunities and increased resistance. Therefore, higher rate application is often favored in low residue scenarios to enhance weed management.