英文原文没有详细解释，我想正是点和线说的那样

Based on an analysis of more than 100,000 U.S. government pesticide test results, researchers at the Environmental Working Group (EWG), a research and advocacy organization based in Washington, D.C., have developed the “dirty dozen” fruits and vegetables, above, that they say you should always buy organic, if possible, because their conventionally grown counterparts tend to be laden with pesticides. They cost about 50 percent more — but are well worth the money.
我自己问过一个美国的果农（摘苹果的时候），他说苹果树从开花以前的两个星期开始打杀虫药，每两个星期打一次，一直打到收获前的三个星期，你说这不是有机的苹果还能吃吗？