Ornamental and Turf Pesticide Applicators Practice Exam

What does Bacillus thuringiensis specifically target for control?

1. Larval stages of caterpillars

2. Root-feeding nematodes

3. Adult beetles

4. Thrips and mites

The correct answer is: Larval stages of caterpillars

Bacillus thuringiensis, commonly referred to as Bt, is a naturally occurring bacterium that is particularly effective in controlling certain insect pests, specifically targeting the larval stages of caterpillars. When ingested by these larvae, the bacterium produces toxins that disrupt their digestive system, ultimately leading to their death. This specificity makes Bt an important tool in integrated pest management, particularly for crops susceptible to caterpillar damage. The focus on larval stages is crucial, as the bacteria are not effective against adult beetles, root-feeding nematodes, or other pests like thrips and mites. Each of these pests has different physiological vulnerabilities, and using Bt would not provide the desired control over insects that do not feed in a way that facilitates the disease caused by this bacterium. Therefore, the effectiveness of Bacillus thuringiensis is largely due to its targeted action on the susceptible larvae, making it a valuable pest control option in various agricultural and ornamental practices.