Citrus Greening or HLB is a disease that is spread by the tiny Asian citrus psyllid bug. The African variation was first reported in 1947 in South Africa, where it is still widespread.
Eventually, it affected the United States, reaching Florida in 2005. Within three years, it had spread to the majority of citrus farms. The rapid increase in this disease has threatened the citrus industry not only in Florida, but the entire US.