Control efficacies of nine herbicides to weeds and their safety evaluation in maize fields

In this study, the control efficacies of nine herbicides against weeds were investigated and their safety in the maize field was evaluated. The efficiencies of nine herbicides at the recommended dosages were carried out using the method of spraying stem and leaves in seed production field for sweet maize. Their risk to sweet maize and post-harvest vegetables (cauliflower and radish) was also studied in the experimental field. The results showed that the control efficiencies of nine herbicides on weed and fresh weight were all above 92% at 25 days after the application. The prevention efficacies of 27% nicosulfuron + mesotrione + atrazine OD (810 g a.i./hm² ) and 25% mesotrione + atrazine OD (750 g a.i./hm² ) were the best ones. And that of 20% fluroxypyr EC (180 g a.i./hm² ) was the lowest one, which showed high degree weed coverage after 50 days. In addition, the tested herbicides were safe and had no negative influence on the growth of sweet maize, and some herbicides could even significantly increase the production. The yield of maize after the treatment by 25% mesotrione + atrazine OD, 20% nicosulfuron + bromoxynil octanoate OD (300 g a.i./hm² ), 80% atrazine WP (1 440 g a.i./hm² ) and 27% nicosulfuron + mesotrione + atrazine OD was higher than that treated by other herbicides. Compared with the control, the yields were increased by 21.03%, 19.26%, 18.74% and 16.84%, respectively. Meanwhile, the treatments of 10% mesotrione SC (150 g a.i./hm² ), 27% nicosulfuron + mesotrione + atrazine OD, 33.5% mesotrione + propisochlor + atrazine SC (1 005 g a.i./hm² ) and 30% topramezone SC (27 g a.i./hm² ) could improve the yield of the post-harvest cauliflower and radish. The increasing rates of yields were 18.05% and 13.68%, 3.37% and 12.67%, 15.45% and 11.06%, and 8.21% and 11.67%, respectively. While the 40 g/L nicosulfuron OD (60 g a.i./hm²) had a negative effect on the yield of cauliflower and radish. The yields were decreased by 9.74% and 3.57% compared with the control. The results could provide scientific basis on selecting and applying effective herbicides to control weeds in sweet corn field.