One stinky bug: The Asian ladybeetle (Photo courtesy of USDA Agricultural Research Service) By Tom Mansell, Science Editor Have you ever picked up an ant and squished it between your fingers? In some cases, the ant has the last laugh, leaving your fingers with a sickly sweet, pungent odor sometimes described as "rotten coconuts." Ants secrete all kinds of different chemicals for communication, stress, antibacterial, antifungal and many other reasons. Unfortunately, this is also true of insects in the vineyard. One particular insect can secrete a chemical so potent, as little as one bug per liter of juice can ruin…