Which statement about pyrethroids is correct?

Pyrethroids are indeed synthetic versions of naturally occurring compounds found in chrysanthemum flowers. These compounds, known as pyrethrins, are used by the plants as a natural defense mechanism against insect pests. Synthetic pyrethroids are chemically modified to increase their effectiveness and stability, especially in various environmental conditions. This alteration enhances their insecticidal properties, making them widely used in agriculture and residential pest control.

In contrast, the other statements do not accurately represent pyrethroids. They are not naturally derived insecticides, as stated in the first option. The second option regarding pyrethroids being relics of historical pesticide use is misleading, as they represent a modern class of chemicals developed to enhance pest management strategies. Lastly, the claim that pyrethroids have no impact on non-target species is incorrect, as they can indeed affect beneficial insects and other non-target organisms due to their mode of action. This knowledge is crucial for informed pesticide application and to mitigate unintended ecological consequences.