Abstract
We conducted greenhouse experiments to investigate the herbicidal activities of pyrazosulfuron-ethyl, flazasulfuron and imazaquin against Cyperus brevifolius var. leiolepis and side effects of these herbicides on Zoysia matrella growth. The results are summarized as follows.
1. Herbicidal activity ; Three herbicides effectively controlled C. brevifolius var. leiolepis, in the order of pyrazosulfuron-ethyl>flazasulfuron>imazaquin. Herbicidal activity of imazaquin was not affected by cutting the grass nor application time after the cutting, while, pyrazosulfuron-ethyl and flazasulfuron provided the highest activity when applied just after cutting.
2. Effects on the Zoysia matrella growth; Excessive application of pyrazosulfuron-ethyl, flazasulfuron and imazaquin at the dosage of 100, 100 and 300 g a.i./10 a, respectively, did not inhibit the growth of Zoysia matrella, while the latter two suppressed the growth of shoot and root, when the top dressing soil was thick or they were applied immediately after cutting of the turf.
These result suggest that pyrazosulfuronethyl, flazasulfuron and imazaquin applications after cutting of the weed offer an effective control of C. brevifolius var. leiolepis. However, to prevent injury of Zoysia turf, attention should be paired for the latter two when the top dressing soil is thick and/or larger dosages are applied just after cutting of the turfgrass.
