Temperature Effects Previous research has shown this bioherbicide effectively controlling weeds under mild temperatures ranging from 15C to 25C [12]. However, prior to this research, it was not known what levels of control could be expected under higher temperatures. Despite the high temperatures around 41 (with mean temperatures of 31C in 2011 and 2TC in 2012) in both years, the bioherbicide provided effective control of slender aster in this study. Based on the results, the bioherbicide appears to retain good efficacy as a natural weed control product during summer months in areas receiving high temperatures, following application. It should be noted, however, that irrigation was provided frequently (4 to 5 times weekly) during this study, and may have also contributed to success of the bioherbicide under these conditions. Daily irrigation may not be agronomically appropriate or feasible in some situations, especially where municipal water restrictions limit the frequency of irrigation allowable on a landscape.