Industrial Hemp Herbicide Tolerance Studies in Virginia.

Industrial hemp (Cannabis sativa L.) is a multipurpose crop that is mainly cultivated for it's fiber and seed content. Hemp stalk can be used as a primary source in auto parts, textile items, industrial products, and building materials. Hemp seeds can be used as a source for human food, animal feed, and cosmetic products. Though, industrial hemp is not considered a commercial crop in Virginia, information is needed on the mode of action and phytotoxicity of herbicides for varying hemp production systems. In 2017, Virginia Tech conducted greenhouse studies to assess a variety of herbicides and their impact on hemp productivity. Several herbicides with different modes of action were tested for their phytotoxicity to hemp. Pre-emergent herbicides were applied at the time of planting and post-emergents were applied when plants reached 8 to 11 in. in height. Our results suggest that pendimethilin, chlorimuron, S-metolachor, linuron, sethoxydim, halosulfuron, and bromoxynil are candidate herbicides for weed control in an industrial hemp production system.