Effect ofdouble-cropping onions behind either pearl millet (Pennisetum glaucum) or corn (Zea mays)
Sour skin, caused by Burkholderia cepacia, is one of the most important postharvest diseases of onion (Allium cepa) in Georgia. Disease incidence usually is greatest in onions harvested in the latter part of April and through May when temperatures are elevated. Previous work in New York indicated that pearl millet (Pennisetum glaucum) decreased soil-borne populations of B. cepacia in contrast with corn (Zea mays) which increased bacterial populations. Anecdotal evidence from growers’ observations also indicated that there were increased levels of sour skin in onions double-cropped with corn. Data are presented from a 5 yr.-study where onions were double-cropped behind either pearl millet or corn. There were no yield data for two of the years because of stand loss due to a freeze and hail damage. However there were reduced levels of sour skin and increased marketable yield in onions following pearl millet for 3 out of 5 years in plots that had been in continuous onion production for 15 yrs. In contrast, sour skin levels were not significantly different in onions following either pearl millet or corn in newly established microplots or in a trial in a commercial field that had no history of onion production.
Nischwitz, C., Boyhan, G., Sanders, F.H., Mullis, S. W., Wilson, J. and Gitaitis, R.D. 2007. Effect of double-cropping onions behind either pearl millet (Pennisetum glaucum) or corn (Zea mays). University of Georgia, , College of Agricultural and Environmental Sciences, 2007 Georgia Onion Research-Extension Report