Effect of bacterial concentration of Xanthomonas campestris pv. poae (JT-P482) on the control of annual bluegrass (Poa annua L.).

摘要

The effect of the concentration of the bioherbicide, X. campestris pv. poae [X. translucens pv. poae], on the control of annual blue grass (Poa annua) was investigated in greenhouse and field experiments conducted at Oyama, Tochigi prefecture, Japanin 1995, by monitoring bacterial multiplication in whole plants and by measurement of efficacy (represented by % of fresh weight loss) over time. In greenhouse experiments, the higher the bacterial concentration initially applied, the greater the efficacy shown and the more rapid the bacterial multiplication observed in P. annua. Since there were no significant differences in efficacy between 108-1010 c.f.u./ml, it is indicated that 108 c.f.u./ml is the most cost efficient concentration for commercialpurposes. In the field trial, significant control was achieved approximately 1 month after treatment and, although, in the greenhouse experiments, efficacy was accelerated by applying larger volumes of water, no significant difference was obtained from any combination of bacterial concentration and water volume in the field trial. Among the many factors affecting the field conditions, it is most likely that the prevailing higher temperature most affected the multiplication of the bacterial cells in theplants resulting in high levels of wilting, because pot-experiments set outdoors to study biotype differences were affected in a similar way by temperature.