Submitted to: Weed Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/18/2012
Publication Date: 10/1/2012
Citation: Williams, M., Pataky, J.K. 2012. Maize dwarf mosaic can reduce weed suppressive ability of sweet corn. Weed Science. 60:577-582. Interpretive Summary: Historically, the ability of a crop to suppress weed emergence, growth, and seed production (hereafter called ‘weed suppressive ability’) has been an important component of weed management in many crop production systems. In sweet corn, weed suppressive ability varies among commercial hybrids, influences herbicide performance, and alters weed seed germination. Maize dwarf mosaic (MDM) is the most prevalent viral disease of sweet corn, and a majority of hybrids have no resistance to MDM. This study investigated the role of MDM incidence on weed suppressive ability of sweet corn. We found that sweet corn hybrid had a larger effect on weed growth and seed production than MDM incidence. Nonetheless, MDM reduced weed suppressive ability of sweet corn. It appears incidence of MDM in sweet corn is a contributing factor to weed escapes in certain fields, because MDM is problematic throughout North America, two-thirds of the commercial sweet corn hybrids have no resistance to MDM, and high weed populations are not uncommon in sweet corn. The impact of this work is that it explains, in part, poor weed control observed in growers’ fields. The research suggests that wider use of MDM-resistance genes in sweet corn would minimize negative effects of both MDM and weed interference, two commonly occurring stresses of the crop.
Technical Abstract: Maize dwarf mosaic (MDM) stunts corn growth, delays development, and is the most prevalent viral disease of sweet corn grown in many regions of North America and Europe. Although weeds evade control in most sweet corn fields, the extent to which MDM influences the weed suppressive ability of the crop is unknown. Field studies were conducted over a three-year period to characterize the influence of variable MDM incidence in sweet corn on growth, fecundity, and germinability of wild-proso millet, a common weed in the crop. Treatments included five levels of MDM incidence (0%, 25%, 50%, 75%, and 100% of plants infected) in two MDM-susceptible hybrids differing in weed suppressive ability. Wild-proso millet biomass and fecundity depended largely on the hybrid in which the weed was growing. Wild-proso millet growing in Sugar Buns weighed 45 to 117% more than wild-proso millet in Legacy. Incidence of MDM in sweet corn affected wild-proso millet biomass and fecundity, but only under high weed population densities. When wild-proso millet was observed at 122 plants m-2, weed biomass increased nine g m-2 for each additional 10% incidence of MDM of sweet corn. Weed suppressive ability of the competitive hybrid (i.e. Legacy) was influenced to the same extent by MDM as the less competitive hybrid (i.e. Sugar Buns). Coupled with the fact that two-thirds of commercial sweet corn hybrids have no resistance to MDM, the disease may be an additional factor perpetuating weed growth and fecundity in sweet corn, particularly in fields with high population densities of wild-proso millet.