One of the most hotly debated issues in California wine these days involves a chemical that can be found in every Home Depot in America: Roundup. Monsanto’s high-profile herbicide is the go-to method of weed control for many California vineyards. … But Roundup’s active ingredient, glyphosate, is probably a carcinogen, according to the World Health Organization. … That revelation has spurred a new outcry in the California wine industry. Some winegrowers who farm according to organic, biodynamic or regenerative protocols — which prohibit the use of glyphosate and other synthetic chemicals — are speaking out against Roundup with renewed fervor, calling for an end to its use in vineyards.