Abstract: Bidens frondosa is an exotic vicious weed which endangers biodiversity. In this study, a field experiment was conducted to investigate the controlling effect of different concentrations and different application periods of herbicides Starane, MCPA, and glyphosate on B. frondosa. All the three herbicides had significant controlling effect on this weed, with the average lethality of Starane, MCPA, and glyphosate being 92%, 85%, and 82%, respectively, but no significant difference among them. Different concentrations of the herbicides (0.47, 0.40 and 0.33g·L^-1 of Starane; 2.80, 2.33 and 1.87 g·L^-1 of MCPA; and 5.18, 3.89 and 2.59 g·L^-1 of glyphosate) had significant differences in the lethality on B. frondosa, and relatively high concentration could obtain better controlling effect. The application period of the herbicides also had significant effects in controlling B. frondosa. Applying the herbicides at B. frondosa seedling stage (plant height 20 cm) could achieve better controlling effect than at its fast growing stage (plant height 40 cm) and blooming stage (plant height 60 cm). It was suggested that applying 0.47 g·L¹ of Starane at the seedling stage of B. frondosa would obtain the best controlling effect.

Key words: solar greenhouses, cucumber, leaf temperature, relative humidity, estimation model.