Alfalfa dwarf disease (ADD) is causing major economic loss in lucerne (Medicago sativa) production in Argentina. Five different viruses are known to be associated with this disease. Alfalfa leaf curl virus (ALCV) is the most likely key virus, leading to severe symptoms and yield losses. ALCV is known to be transmitted by the aphid Aphis craccivora and is found infecting lucerne in South America, the Mediterranean region and the Middle East. There is a risk of accidental introduction of ALCV into Australia. Potential pathways of ALCV entry are through viruliferous aphids or infected host plants. Biosecurity measures should be put in place to prevent its entry. Grower vigilance and early detection will be key to keeping the industry safe from ADD.