Issue link: http://read.dmtmag.com/i/643470
www.goodfruit.com GOOD FRUIT GROWER MARCH 1, 2016 25 I f brown marmorated stinkbugs have emo- tions, they must be terrifi ed of a baby killer named Trissolcus japonicus. Growers might be fi ne with that given the threat posed by brown marmorated stinkbugs (BMSB). These stinkbugs, which are not native to North America, are voracious eaters that damage fruit, vegetable and ornamental plants. They also reproduce well: The stinkbugs overwin- ter as adults and emerge in the spring to begin mating, and a single female can deposit hundreds of eggs in her lifetime. A parasitic wasp, Trissolcus japonicus, could be the perfect weapon to defeat them. About the size of a flea, T. japonicus visits stinkbug egg clusters, attracted by the scent left by glands on stinkbug feet. T. japonicus jabs its ovipositor, a tube-like organ, into stinkbug eggs and injects its own eggs. The wasp's larvae gain nourishment by eating baby stinkbugs before they hatch. If this reminds you of the science fi ction Alien movies, scientists agree. In the movies, the alien larvae consume their hosts from within and even- tually burst out. T. japonicus does something similar, which makes it a surprisingly effi cient killer of stinkbugs. "They're pretty amazing creatures," said Dr. Kim Alan Hoelmer, an entomologist and acting director of the U.S. Department of Agriculture Overseas Biological Control Laboratories. He knows growers would be happy to see T. japonicas authorized as a stinkbug control, a step subject to federal review. So far, tests of chemical controls have not been promising, in part because stink- bugs can overwinter in protected places and move in and out of orchards. (See "Stinkbug continues its spread," Good Fruit Grower, December 15, 2015.) The T. japonicas lifecycle is correlated to stink- bugs, but the adult wasps can live independently for months just on water or fl ower nectar. When a female T. japonicas fi nds a stinkbug egg mass, it deposits one of its eggs in each of the host eggs. The emerging T. japonicas are just 1.5 millimeters long, so tiny that scientists need microscopes to examine body parts. Males develop faster than females and emerge fi rst and wait for their mates. When females emerge, the two mate, fertilizing the females, and off they go. "It's a rather strange but fascinating life cycle," Hoelmer said. Scientists have not clocked the speed of their flight but T. japonicas has enough strength to make progress against wind. "These wasps are kind of muscle-bound," he said. Hoelmer's interest in Trissolcus japonicus began after brown marmorated stinkbugs were discovered on the East Coast in the mid-1990s. A Cornell University entomologist, Richard Hoebeke, in 2001 determined that BMSB had come from Asia. BMSB has proven to be a much STINKBUG'S NIGHTMARE A wasp no bigger than a fl ea could be the best tool against brown marmorated stinkbug. by O. Casey Corr A Trissolcus japonicus parasitoid wasp emerges from a brown marmorated stinkbug egg at the USDA-APHIS Quarantine Facility in Corvallis, Oregon. PHOTO ILLUSTRATION COURTESY CHRISTOPHER HEDSTROM