Pigweed is difficult to manage in grain sorghum because of widespread herbicide resistance, a limited number of registered effective herbicides, and the synchronous emergence of pigweed with grain sorghum in Kansas. The combination of cultural and mechanical control tactics with an herbicide program are commonly recognized as best management strategies; however, limited information is available to adapt these strategies to dryland systems. Our objective for this research was to assess the influence of four components, including a winter wheat cover crop (CC), row-crop cultivation, three row widths, with and without a herbicide program, on pigweed control in a dryland system. Field trials were implemented during 2017 and 2018 at three locations for a total of 6 site-years. The herbicide program component resulted in excellent control (>97%) in all treatments at 3 and 8 weeks after planting (WAP). CC provided approximately 50% reductions in pigweed density and biomass for both timings in half of the site-years; however, mixed results were observed in the remaining site-years, ranging from no attributable difference to a 170% increase in weed density at 8 WAP in 1 site-year. Treatments including row-crop cultivation reduced pigweed biomass and density in most site-years 3 and 8 WAP. An herbicide program is required to achieve pigweed control and should be integrated with row-crop cultivation or narrow row widths to reduce the risk of herbicide resistance. Additional research is required to optimize the use of CC as an integrated pigweed management strategy in dryland grain sorghum.

Rhizobacteria are being evaluated for promotion of plant growth and for biological control of weeds, insects, diseases, and nematodes. Although considerable efforts have been allocated to this approach to biological control, commercial success remains elusive yet intriguing. In this review, the root biology of downy brome and winter wheat is described as an initial model of the information needed for other plant hosts. A limited review of rhizobacteria in disease management is presented to demonstrate the potential and some limitations with rhizobacteria as biocontrol agents. Several techniques are described to improve the survival of a rhizobacterium to suppress downy brome. To achieve success with rhizobacteria in pest management, more information is needed on the root biology of the host plants and the ecology of the rhizobacteria.