The herbicides, which penetrate rice plants through leaves, stalks and roots, have proved very effective for annual and perennial weeds.

Prof. and Dr. Kim Chi Yong, director of the institute, told KCNA that in the past different kinds of herbicides were applied to different sorts of weeds, consuming much labor and cost.

He, who is also a candidate academician, said the institute, based on the analysis of the existing herbicides' characteristics, tried to make new ones capable of killing various weeds simultaneously, while giving no harmful effect to ecological environment and human body.

"The new herbicides we developed kill most of weeds with a small amount," he added.