a substituted benzoyl derivative having the formula : ## str1 ## wherein x 1 is c 1 - c 4 alkyl , c 2 - c 5 alkoxyalkyl , c 1 - c 4 haloalkyl , c 1 - c 4 alkoxy , c 1 - c 4 haloalkoxy , cyano , nitro or halogen ; x 2 is -- l -- or 1 , -- l -- o -- l -- or 1 , -- l -- s n -- r 2 , -- l -- o -- cor 2 , -- l -- nr 1 r 3 , -- coor 1 or -- coo -- l -- o -- r 1 , provided that when x 1 is c 1 - c 4 alkyl or c 1 - c 4 haloalkyl , x 2 is not -- coor 1 ; x 3 is trifluoromethyl , c 1 - c 3 alkoxy , halogen , cyano , nitro or -- s n r 4 ; x 4 is hydrogen , c 1 - c 4 alkyl , c 1 - c 4 alkoxy or halogen ; x 5 is hydrogen or fluorine ; and each of y 1 , y 2 , y 3 , y 4 and y 5 is hydrogen or c 1 - c 4 alkyl ; or a salt thereof .