Pre-emergence herbicidal activity of NSK-850 and its effects on the growth of turfgrasses
1990 Volume 18 Issue 2 Pages 145-152
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1990 Volume 18 Issue 2 Pages 145-152
In order to prove the usefulness of NSK-850 as a turf herbicide, pre-emergence herbicidal activity of the chemical and its influence on the growth of turfgrasses were examined by pot tests in green house. The results obtained were summarized as follows.
1. Pre-emergence herbicidal activity
(1) Herbicidal spectrum of NSK-850 by preemergence treatment.
NSK-850 effectively controlled annual grassy weeds such as Poa annua, Setaria viridis and Digitaria cilialis. at a dosage of less than 3 g a.i./a. Broadleaved weeds including Bidens pilosa, Ipomoea indica, Capsella bursa-pastris were rather tolerant to the herbicidal and were not controlled even at a dosage of 100 g a.i./a (Table 3) .
(2) Effects of soil water content on the preemergence herbicidal activity of NSK-850.
An excellent control of Setaria viridis was obtained at the highest soil water content (39.3%, W/W) (Fig. 1) .
(3) Effects of spray volume on the preemergence herbicidal activity of NSK-850.
In general, spray volume greatly affected the efficiency of the applied herbicide, and an optimum spray volume for the control of Digitaria ciliaris and Setaria viridis was 10 1/a (Fig.2) .
2. Influence of NSK-850 and simazine on the growth of turfgrasses.
(1) Treatment after cutting off the shoots of turfgrasses.
NSK-850 did not affected the growth of both Zoysia japonica and Zoysia matrella but showed a slight phytotoxicity on Agrostis palustris.
(2) Treatment after top dressing.
When Utsunomiya upland soil (diluvial loam soil) was used for top dressing, the growth of Zoysia matrella was inhibited by simazine but not by NSK-850. Both of the herbicides, however, inhibited the growth of the turfgrasses when Kinugawa coast soil (alluvial sandy loam) was used for top dressing.
(3) Root treatment
When the herbicides were applied to the roots of the turfgrasses, among them Agrostis palustris showed the highest susceptibility to NSK-850 and simazine.
In conclusion, it was suggested that NSK-850 is an useful preemergence herbicide for the control of annual grassy weeds in Zoysia japonica and Zoysia matrella, but it should not be applied directly to the roots
