Heretofore, various herbicides have been developed to contribute toward promoting the agricultural producibility and energy-saving. However, since some herbicides have been used for a long period of time, weeds which could hardly be blighted or exterminated by such herbicides are increasing. Therefore, realization of herbicides having a broader herbicidal spectrum and being effective to even such troublesome weeds is desired. In addition, in order to solve the problem of environmental pollution by conventional herbicides, development of herbicides having a higher activity is also desired. Moreover, in order to control weeds emerging non-uniformly over a long period of time, it has been desired to develop herbicides having excellent residual activities and having flexibility of treatment to exhibit effectiveness, even though the treatment is performed over a long period of time from preemergence to a wide range of growing stage of weeds.
Under the situation, it was already found that particular novel haloalkyl-having triazine derivatives show a high herbicidal effect against troublesome weeds both by soil treatment and by foliage treatment without phytotoxicities of Gramineae crops , and especially that such derivatives show an excellent herbicidal effect against weeds in paddy fields (International Patent Application Laid-Open No. WO 90/09378). The present inventors further made earnest studies so as to improve the herbicidal activity of the triazine derivatives.