Citrus greening disease, or Huanglongbing (HLB), is considered to be the most destructive disease of citrus. It is endemic in large parts of Asia and Africa, and has recently invaded the Americas. It is caused by a bacterium which is transmitted by insects called psyllids. There is no cure for greening, and the lengthy latent period after infection makes eradication almost impossible.The disease is now in Brazil, Cuba, Belize, southern Mexico and six US states (California, Florida, Louisiana. South Carolina, Georgia, Texas).