A colleague at Ohio State University (sorry, I mean The Ohio State University) shared a recent series of extension publications they put together related to specialty crop injury from the auxininic herbicides dicamba and 2,4-D.  

Dicamba and 2,4-D Fact Sheet Series

Admittedly (and thankfully!) we do not have the same challenges with these herbicides in California specialty crops as they do in the Midwest where small grains, corn, and more recently dicamba- or 2,4-D-tolerant soybeans are grown on millions of acres.  However, I thought these fact sheets were well done and provide relevant information with regard to herbicide drift and investigating and documenting herbicide injury.

Link to landing page: https://ipm-drift.cfaes.ohio-state.edu/dicamba-and-24-d-fact-sheet-series