Cruciferous flea beetle (Phyllotreta cruciferae). The cruciferous flea beetle (Phyllotreta cruciferae) can leave you without a harvest of Chinese cabbage and more. The cruciferous flea beetle is a dangerous pest that attacks cabbage, radishes, turnips and other cruciferous crops. There are many methods of dealing with this pest, but my method is simpler (I checked it twice last season). 1. I remove the cover from the cabbage bed; the cruciferous flea beetle will feel uncomfortable in the open ai