Can you identify beetle
I hope you can identify this insect, I think beetle, but not leaf beetle. The above photo shows it to be 3/8 inch. The below photos shows a pair (mating?). My location is San Luis Valley, Colorado. 8,000 ft elevation. Very arid. I first saw them at our creek on tumble mustard. A couple a days later they arrived in the garden 500 feet away on the horse radish leaves (probably 100). There are only a couple on the potatoes which are next to the horse radish. None on any other garden produce. Any ideas? Are they harmful or beneficial? What can discourage them? Thanks,
These are winged adult Harlequin Bugs, Murgantia histrionica. They do feed on mustard in vacant lots and fields. When they move to the garden they infest cabbage, kale, collards and related plants. The best control is to locate the eggs which are barrel shaped and in rows. Hand picking will also do the trick. Also, when your crop is harvested, immediately remove any remaining plants that serve to perpetuate the infestation.