Herbicidal benzo triazinones

The present invention provides benzoxazinones of formula I, wherein R1 is hydrogen or halogen; R2 is hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, C3-C6 cycloalkyl, C3-C6 alkenyl group, C3-C6 haloalkenyl, C3-C6 alkynyl group, C3-C6 haloalkynyl, C1-C6 alkoxy or C3-C6-cycloalkyl -C1-C6 alkyl; R3 is halogen; R4 is a halogen ; X is O or S; and Y is a substituted or unsubstituted heterocyclic ring; the formula I can be used as herbicides benzoxazinones.