Monday, July 13, 2020

“Threatening our signature crop”

Adult Citrus Greening.

Adult Citrus Greening.

By Yvette Benarroch

Citrus greening has seriously affected citrus crops in the United States, Asia and Africa.  The disease was detected in Florida in 2005 and it is threatening our citrus industry.  This will have environmental, economic and social impacts in our State.

What is citrus greening?

Citrus greening is bacterial disease that slowly weakens and kills all types of citrus trees and it is one of the most serious citrus diseases in the world. It just affects citrus plants and it doesn’t represent a threat to humans or animals.

What causes citrus greening?

Citrus greening disease is caused by phloem-limited bacteria in the genus Candidatus Liberibacter and it is primarily spread by two species of psyllid insects: the Asian citrus psyllid and the African citrus psyllid.  Both species transport the citrus greening pathogen from infected trees to healthy trees as they feed on the plant.  The disease is not spread by wind, rain or through contaminated tools and the psyllid must be infected to spread the disease.  In the United States only the Asian citrus psyllid has been found.

The adult Asian citrus psyllids are about 3-4 mm and they have mottled brown wings.  They are very active jumping insects and leap when disturbed. The eggs are bright yellow to orange in color and the nymphs are generally yellowish orange. The nymphs are always found on new growth. Its population increases during the periods of active plant growth.

What are the symptoms of citrus greening?

Common symptoms

Citrus Greening.

Citrus Greening.

are yellowing of the veins and adjacent tissues, followed by yellowing or mottling the entire leaf. The disease may also cause small, narrow leaves and short stems that give plant growth a bunched appearance.  Other symptoms include twig dieback, poor flowering, and stunted growth. The fruit form diseased trees is small and it has a bitter, medicinal and sour taste.

The symptoms will vary according to time of infection, stage of disease, tree species and tree maturity. It can initially be difficult to diagnose because symptoms may not be displayed for some time.  It can also be misdiagnosed with zinc or manganese deficiency.

Is there a cure for citrus greening?

Currently there is not known cure for the disease and it is strongly recommended to remove any diseased tree. Prior to removal the tree needs to be treated with a foliar insecticide to kill all adult psyllids feeding on that tree.

If you have any questions or if you would like me to write about a particular subject   please send it to Yvette@alsmarco.com

Yvette is a Florida Certified Pest Control Operator in general household pest control and lawn and ornamental spraying.  She completed studies in Entomology and Pest Control and holds a Pest Control Technology certificate from the University of Florida.  She is a Licensed Landscape Contractor in Collier County and has a Bachelor’s degree in Marketing from Interamerican University of Puerto Rico.  Yvette and her husband Al are the owners of Affordable Landscaping Service and Design, LLC. a company that offers Landscaping Design, Lawn Care, Tree Trimming and Pest Control Services.

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