Illinois Field Crop Applicators Practice Test

What is the primary pest that results in bronzing leaves and curled leaves?

1. Bean leaf beetle larvae

2. Spider mites

3. Soybean aphids

4. Alfalfa weevil larvae

The correct answer is: Bean leaf beetle larvae

The primary pest that leads to bronzing leaves and curled leaves is the bean leaf beetle larvae. These larvae cause specific damage to the leaves of soybean crops, leading to a bronzed appearance due to tissue damage. This pest feeds on the leaves, resulting in characteristic curling, which is a noticeable symptom of its presence. The damage can adversely affect the plant's ability to photosynthesize and could lead to decreased yields if not managed properly. While spider mites can also cause leaf bronzing and curling, they typically affect plants differently and often leave a stippled appearance rather than the specific curling associated with bean leaf beetle larvae. Soybean aphids primarily suck sap from the plants and cause yellowing rather than bronzing, and alfalfa weevil larvae primarily infest alfalfa, making the damage they cause not applicable in this context. Thus, the identification of the bean leaf beetle larvae as the primary pest is crucial for effective crop management and control strategies.