Beet Curly Top Virus in Industrial Hemp

Curly top of sugar beet, caused by Beet Curly Top Virus (BCTV), was first reported in Nebraska in 1888. BCTV has since become widespread in the arid and semiarid parts of the Western United States, the Mediterranean Basin and Middle East. It has caused frequent and often very destructive outbreaks on many commercial crops throughout the Western United States. In Arizona, BCTV is a very serious plant virus affecting hemp and hundreds of ornamental and commercial crops. Hemp appears to be a highly susceptible host for the virus, in particular young plants are most susceptible to infection spread by he beet leafhopper insect. BCTV typically causes upward curling of the leaves associated with vein clearing and the tumorous outgrowths (enations on the lower surface of veins) as well as a reduction in chlorophyll content and the rate of photosynthesis. The resulting curly top disease significantly reduces yield potential of the plant if it is infected at young age. Due to the wide distribution of beet leafhoppers and abundant range of host plants for the virus, BCTV may become one of the most yield limiting factors affecting the emerging industrial hemp production systems in Arizona.