Accelerated development of bioherbicides to control Palmer amaranth (pigweed).
Palmer amaranth (Amaranthus palmeri), a competitive pigweed native to desert regions of the southwestern United States and northern Mexico, has become one of the most significant weed pests affecting soybean, corn, and cotton producers in Arkansas. Both invasive and aggressive, its vast genetic variability has helped it evolve resistance to herbicides relatively quickly. The current tools available to control pigweed are limited and unsustainable; thus, an effective integrated weed management approach is required to achieve control. Native pigweed pathogens could provide effective biological control of these weeds, especially if the virulence of pathogens can be increased through non-transgenic means. Thus, the objectives of this research are to: (1) evaluate fungal pathogens of pigweed to identify highly aggressive isolates (potential bioherbicide strains) (2) increase the aggressiveness of selected isolates through molecular genetic (non-transgenic) approaches and (3) evaluate modified strains and select candidates to commercialize as bioherbicides of pigweed.