Friend or foe?
Beetle larvae typically look like grubs and live in the soil, or sometimes inside stems of plants. The pictures are a little blurry on my screen but, these appear to be caterpillars. Caterpillars are the immature form of moths and butterflies.
Caterpillars on edible plants can be controlled by knocking them off into soapy water, then discarding the water after they have been killed. Bt sprays are effective against caterpillars-
You can use any insecticide labeled as safe for use on grapes. Please read the label and be sure the product is safe to use on edibles-https://pender.ces.ncsu.edu/2013/09/controlling-caterpillars-in-vegetable-gardens/
For a fee, MSU Plant and Pest Diagnostic lab can identify fresh whole insect samples packaged in white vinegar in a water-tight vial or small jar. See their website for details- https://pestid.msu.edu
Or, if you can get a clear closeup of a couple, perhaps on a plain sheet of paper, I can refer this to an entomologist.
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