Citrus tristeza disease, caused by Citrus Tristeza Virus is a worldwide disease of citrus. Tristeza has seriously destroyed the citrus industry which had once got close to the breakup in South America nations such as Brazil.

• 由柑桔衰退病毒(Citrus tristeza virus，CTV)引起的柑桔衰退病是世界性的柑桔病害，对柑桔产业造成了严重威胁，巴西等南美国家曾一度因此病危害而使柑桔产业濒临崩溃。