Claim 1: A derivative of arylalkyloxypyrimidine oxide represented by formula (1) characterized in that R¹ is (a1) a halogen atom； (a2) a formyl group； (a3) a cyano group； (a4) a C₁₋₈ alkyl group；(A5) one cycloquilo c83231-8328；(A6) un grupo alquenilo C(a7) a C₂₋₈ alkynyl group；(A8) a c832131 halide group；(A9) one c833238331-8328；(A10) un grupo haloalquenilo C(a11) a C₂₋₈ haloalkynyl group；(a12) a C₁₋₈alkyl C₁₋₈alkoxy group；(a13) a C₃₋₈ cycloalkyl C₁₋₈ alkyl group；(a14) a C₁₋₈alkyl-C alcoalkoxy group；(a15) a C₃₋₈-alkyl alkyl C ciclo-cycloalkyl group；(a16) a C₁₋₈-alkyl alkyl group Cio；(A7) c8321 asphalt formation； c83231-8328； c83318328；(a18) a C₁₋₈alkyl Cilsalkyl sulfonyl group；(a19) a C₁₋₈alkyl haloalkoxy group；(a20) a halocycloalkyl C₃₋₈alkyl group；(A21) a c8332111 halo asphalt formation； 83833183；(a22) a haloalkylsulfinyl C₁₋₈alkyl C₁₋₈ group；(a23) a haloalkylsulfonyl C₁₋₈alkyl C₁₋₈ group；(a24) a haloalkoxyhalo C₁₋₈alkyl group；(A25) un grupo cianoalquilo C(A26) un grupo nitroalquilo C(a27) a group R⁴ (R⁵) N-alkyl C₁₋₈ where R⁴ and R⁵ may be the same or different and each is (i) a hydrogen atom, (ii) a C₁₋₆ alkyl group,(III) one cycloquilo c83231；(Iv) un grupo alquenilo C(v) a C₂₋₆ alkynyl group,(VI) one cycloquil c83231 and 832626； lease c83231 and 832626；(vii) a C₁₋₆ haloalkyl group,(VIII) one c83231-832626 halopropylene；(Ix) un grupo haloalquenilo C(x) a C₂₋₆ haloalkynyl group,(xi) a halocycloalkyl C₃₋₆alkyl C₁₋₆ group,(XII) asphalt group c832131；(XIII) asphalt formation C 832131；(xiv) a C₁₋₆ haloalkylcarbonyl group,(xv) a C₁₋₆ alkoxycarbonyl group,(xvi) a C₃₋₆ cycloalkylcarbonyl group,(xvii) a phenyl group, (xviii) a phenyl group having, on the ring, the same or different 1 to 5 substituents selected from (a) a halogen atom, (b) a C₁₋₆ alkyl group,(c) a C₁₋₆ haloalkyl group,(d) a C₁₋₆ alkoxy group,(e) One haloalcoxy c832131；and (f) a phenoxy group, (xix) a phenoxy-phenyl group having, on the ring, the same or different 1 to 5 substituents selected from (a) a ha
