Compositions and methods for controlling weeds in crops

1. A method of selectively controlling glyphosate- or glufosinate-resistant volunteer crop weeds in a desired crop, comprising applying to volunteer crop weeds a herbicidally effective amount of a composition comprising bromoxynil or bromoxynil octanoic acid ester plus glyphosate or glufosinate, plus a protoporphyrinogen oxidase inhibitor, wherein said volunteer crop weeds are selected from the group consisting of canola, genetically modified canola and mixtures thereof and wherein combinations of the protoporphyrinogen oxidase inhibitor plus glyphosate or glufosinate plus bromoxynil or bromoxynil octanoic acid ester exhibit a synergistic effect in control of the canola when compared to combinations of protoporphyrinogen oxidase inhibitor plus glyphosate or glufosinate and combinations of bromoxynil or bromoxynil octanoic acid ester plus glyphosate or glufosinate.

2. The method of claim 1 , wherein said protoporphyrinogen oxidase inhibitor is selected from the group consisting of carfentrazone, sulfentrazone, fluthiacet-methyl, saflufenacil, and mixtures of two or more thereof.

3. The method of claim 1 , wherein said protoporphyrinogen oxidase inhibitor comprises carfentrazone.

4. The method of claim 1 , wherein said volunteer crop weeds are in the 1-6 leaf stage.

5. The method of claim 1 , wherein said desired crop is selected from the group consisting of genetically modified and non-modified corn, wheat, oat, rye, soybean, cotton, flax, jute, rape, canola, linseed, sesame, safflower, sunflower, clover, beet, sugar beet, sorghum, millet, rice, peanut, pea, bean, cucumber, pepper, melon, cabbage, onion, squash, lettuce, asparagus, eggplant, tomato, tobacco, flower seed and turfgrass.

6. The method of claim 1 , wherein said desired crop is selected from the group consisting of canola, genetically modified canola, and mixtures thereof.

7. The method of claim 1 , wherein said composition comprises a tank mix of formulated bromoxynil and a formulated protoporphyrinogen oxidase inhibitor.

8. The method of claim 7 , wherein said protoporphyrinogen oxidase inhibitor is carfentrazone-ethyl.

9. The method of claim 1 , wherein an applied rate of bromoxynil and/or an applied rate of protoporphyrinogen oxidase inhibitor is less than registered application rate for control of the volunteer crop weed.

10. The method of claim 8 , wherein an applied rate of bromoxynil and an applied rate of carfentrazone-ethyl are each half of their registered rates for control of the volunteer crop weed.

11. The method of claim 1 , wherein control of said volunteer crop weed is effective

through at least 21 days post treatment.

12. The method of claim 4 , which is effective to control mature volunteer crop weeds.

13. A herbicidal composition comprising a synergistically effective amount of bromoxynil or bromoxynil octanoic acid ester, a plus protoporphyrinogen oxidase inhibitor, plus a glyphosate or a glufosinate, wherein the herbicidal composition is effective to selectively control volunteer crop weeds in a crop, and wherein said volunteer crop weeds are selected from the group consisting of canola, genetically modified canola and mixtures thereof and wherein combinations of the protoporphyrinogen oxidase inhibitor plus glyphosate or glufosinate plus bromoxynil or bromoxynil octanoic acid ester exhibit a synergistic effect in control of canola when compared to combinations of protoporphyrinogen oxidase inhibitor plus glyphosate or glufosinate and combinations of bromoxynil or bromoxynil octanoic acid ester plus glyphosate or glufosinate.

14. The herbicidal composition of claim 13 , wherein said protoporphyrinogen oxidase inhibitor is selected from the group consisting of carfentrazone, sulfentrazone, fluthiacet-methyl, saflufenacil, and mixtures of two or more thereof.

15. The herbicidal composition of claim 13 , wherein said protoporphyrinogen oxidase inhibitor comprises carfentrazone.