WEED GROWTH RETARDANT

PROBLEM TO BE SOLVED: To obtain an agrochemical composition usable as a weed growth retardant, capable of retarding plant growth without blighting and usable on a slope such as a face of slope, and levees, by including an ingredient comprising a phosphorus acid derivative, etc., in a non-selective herbicide. SOLUTION: This composition comprises (A) the first herbicidally active ingredient selected from the group of non-selective phosphoric acid-based herbicides, such as N-(phosphonomethyl)glycine (its salt) and N,N-bis(phosphonomethyl)glycine (its salt), (B) the second ingredient selected from phosphorus acid derivatives expressed by the formula I [R is a 1-8C alkyl (substituted with 1-3 halogen(s) or phenyl, etc.; M is H, an ammonium (substituted with one to four 1-3C alkyl(s)), Na, Al, etc.; (m) is a number equal to the valence of M] and chitosans expressed by formula II [(n) is an integer of one or more; R is H or a 1-6C alkyl, etc.], and optionally, (C) the third ingredient selected from plant growth regulators, disinfectants (ergosterol biosynthesis inhibitors), etc.