Biology and control of wild-proso millet (Panicum miliaceum)

摘要

Field research was conducted on the biology and control of wild-proso millet (PANMI) between 1988 and 1995. The results of those experiments are recorded in the five chapters of this dissertation. The first part of chapter one deals with the longevity of PANMI seed banks and the influence of seed rain on PANMI seed banks. This work led to the development of a model that predicts future seed banks based on the previous years seed bank and seed rain. The model can be manipulated to estimate the number of seed that can be returned as seed rain without increasing future PANMI seed banks. The second part of chapter one focused on PANMI fecundity and influence of herbicides on PANMI fecundity. The seed production models from the second and third parts of chapter one were combined into one model and used to estimate PANMI seed rain based on the number panicles per plant and the level of late season control from herbicides. In chapter 3 eight integrated management systems were compared for their long-term effect on PANMI seed banks. Seven of the eight systems reduced PANMI seed banks by 98% after three years. The management systems included crop rotation, herbicide rotation, cultivation, and post-directed treatments. PANMI control in sweet corn with nicosulfuron was evaluated in chapter 3. Based on PANMI control and sweet corn yield, the optimal time to apply nicosulfuron was when PANMI was 8 to 10 cm tall. Paraquat and sethoxydim were evaluated in chapter 4 for PANMI control in sweet corn. Both paraquat and sethoxydim gave excellent PANMI control when applied post-directed with either and extended-arm sprayer or cultivator sprayer. Management systems, similar to those used in chapter two, were investigated for their ability to prevent the establishment of PANMI into new areas. Excellent PANMI control was achieved in alfalfa, field corn, peas, snap beans, soybeans, sweet corn, and wheat using the systems investigated in chapters two and five. However, the systems must be well planned and executed to achieve season long PANMI control.