FIELD EFFICACY OF VERTICILLIUM-LECANII, SEX-PHEROMONE, AND PHEROMONE ANALOGS AS POTENTIAL MANAGEMENT AGENTS FOR SOYBEAN CYST-NEMATODE

A soybean cyst nematode sex pheromone (vanillic acid), chemical analog s of the pheromone, and the fungus Verticillium lecanii were applied i n alginate prills (340 kg/ha) to microplots and small-scale field plot s as potential management agents for Heterodera glycines on soybean. I n 1991 microplot tests, treatment with V. lecanii, vanillic acid, syri ngic acid plus V. lecanii, or vanillic acid plus V. lecanii lowered mi dseason cyst numbers compared with the untreated susceptible cultivar control, autoclaved I! lecanii treatment, or aldicarb treatment. At-ha n est cr;st numbers were lowest with lr lecanii and with vanillic acid treatments. Aldicarb treatment reduced midseason cyst numbers in 1992 . There were no differences among seed yields either year. In the fiel d trials, numbers of cysts were reduced one or both years with aldicar b, ferulic acid, syringic acid, vanillic acid, or 4-hydroxy-3-methoxyb enzonitrile treatments, or with a resistant cultivar, compared to an u ntreated susceptible cultivar. Highest yields were recorded after trea tment with 4-hydroxy-3-methoxybenzonitrile (1991), methyl vanillate (1 992), and aldicarb (1992). These studies indicate that some chemical a nalogs of vanillic acid have potential for use in soybean cyst nematod e management schemes.