Submitted to: Journal of Nematology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/1/1997
Publication Date: N/A
Citation: Interpretive Summary: Plant-parasitic nematodes are small worms that attack plants and cause seven billion dollars worth of agricultural losses each year in the U.S. Damage from soybean cyst nematode (SCN) causes more soybean yield losses in the U.S. and other major soybean-growing countries than damage from any other single disease. A sex pheromone (a compound given off by female nematodes that is involved in reproduction), compounds similar to the sex pheromone, and the fungus Verticillium lecanii (which attacks SCN) were tested as possible management agents for SCN. In microplots (small circular areas in a field) there was no consistent effect of any agent on SCN numbers or on soybean yields. In larger field tests, plots with a resistant cultivar (on which it is difficult for SCN to grow) or with a conventional chemical nematicide treatment had less SCN during the growing season than plots planted with soybeans that were not resistant to SCN. The experimental treatments did not affect SCN numbers, but two of the compounds similar to the pheromone increased soybean yields. These studies indicate that some compounds similar to a SCN sex pheromone have potential for use in SCN management schemes. The results will be used by scientists developing environmentally safe management schemes for reducing crop losses caused by SCN.
Technical Abstract: A soybean cyst nematode (SCN) sex pheromone, chemical analogs of the pheromone, and the fungus Verticillium lecanii were tested in microplots and field plots to determine their potential as management agents for SCN. The sex pheromone, vanillic acid (VA), is involved in mate finding and male coiling required for fertilization; the chemical analogs tested were ferulic acid (FA), syringic acid (SA), methyl vanillate (MV), and 4-hydroxy-3-methoxybenzonitrile (HM). All agents were applied in alginate prills at 340 kg/hectare (300 lb/acre). At midseason in 1991, microplots treated with V. lecanii, VA, SA plus V. lecanii, or VA plus V. lecanii had lower cyst numbers than microplots with untreated susceptible controls, autoclaved V. lecanii treatment, or aldicarb treatment (a conventional chemical nematicide). Cyst counts at end-of-season were lowest with V. lecanii, VA, and SA treatments. There were no significant differences in cyst numbers in 1992 or 1993, and no differences among seed yields in any microplot tests. In field tests (1991 and 1992), plots with the resistant cultivar or with aldicarb treatment had lower midseason cyst counts than controls. Treatment with MV or HM resulted in the highest yields. These studies indicate that some chemical analogs of SCN sex pheromone have potential for use in SCN management schemes.