Which organic pesticide can typically be derived from plant sources?

The correct answer is pyrethrin, which is an organic pesticide derived from the flowers of the chrysanthemum plant, specifically the species Chrysanthemum cinerariifolium and Chrysanthemum coccineum. Pyrethrin works by targeting the nervous system of insects, leading to their paralysis and death upon exposure. Its plant origin makes it a popular choice for organic pest control, as it is considered to be less harmful to the environment and beneficial insects compared to synthetic pesticides.

In contrast, glyphosate and chlorpyrifos are synthetic chemicals. Glyphosate is a widely used herbicide that targets a specific enzyme pathway in plants, while chlorpyrifos is a synthetic insecticide approved for commercial agriculture, known for its neurotoxic effects on insects. Bacillus thuringiensis, though a natural bacterium used as a biological pesticide, is not derived from plants but rather from a soil-dwelling bacterium. Overall, the focus on a pesticide's plant-based origins solidifies pyrethrin as the correct answer in this context.