Citrus Greening Disease

What is Citrus Greening?

• Citrus greening, also known as Huanglongbing (HLB), is a bacterial disease that attacks the vascular system of citrus plants.
• It is transmitted by tiny insects called psyllids and has no cure once a tree is infected.

History of Citrus Greening

• Citrus greening was first reported in China in 1919, then in the Philippines in 1921, Thailand in the 1960s, Brazil in 2004, and Florida in 2005.
• It has since spread to other states in the US, including Louisiana, Georgia, and South Carolina, as well as countries like Cuba, Mexico, South Africa, India, and the Saudi Arabian peninsula.

Symptoms of Citrus Greening

• Symptoms of citrus greening include:
  • Twig dieback
  • Leaf yellowing
  • Green, misshapen fruit
  • Blotchy mottle on leaves (a random yellowing pattern)
  • Yellow leaf veins
  • Salty, bitter tasting fruit
  • Off-season blooming
  • A curved central core inside the fruit

Treatment and Management

• Once a citrus tree is infected, there is no cure, but researchers are working to control the disease and develop HLB-resistant citrus varieties.
• Management strategies include:
  • Quarantine regulations to prevent the spread of the disease
  • Removing infected citrus plants
  • Applying insecticides
  • Planting/grafting HLB-free citrus plants

The Cost of Citrus Greening

• The disease has been devastating to the citrus industry, with approximately 80% of Florida citrus trees infected.
• HLB reduces crop production by about 40% and increases control and management costs by around $400 per acre.
• The disease has also led to job losses across the industry, with many farmers going out of business.