“causal agent”造句，怎麼用causal agent造句

Symptoms and morphological characters of the causal agent of a newly recorded disease,the common corn rust in Xinjiang

[2] Vincent v. Lake Erie Transport was a superb decision, for there the court was careful to investigate the causal agent at work—in this case, the boat, which clearly slammed against the dock.

Crown rust is the common name both of a serious leaf-rust disease of oats and of the causal agent.

Could you tell me the main causal agents of plant diseases?