For the past 13 years Florida’s citrus farmers’ crops have been plagued by Huanglongbing (HLB), or Citrus Greening, a bacterial disease spread by the Asian Citrus Psyllid, an insect pest. This small insect, no bigger than a grain of rice, has had devastating affects on Florida’s citrus agriculture. Resulting in a dramatic decline in citrus production, that has had a harrowing effect on growers, employees, commercial outlets, and consumers.

What is Citrus Greening?

small brown insect with marbled colored leaves, resting on a bright green leaf

David Hall [Public domain], via Wikimedia Commons

discolored yellowish leaves and green fruit hanging on a citrus tree infected with citrus greening

Florida Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org – See more at: http://www.invasive.org/browse/detail.cfm?imgnum=5201066#sthash.mXgDU61g.dpuf [CC BY 3.0], via Wikimedia Commons

Citrus Greening is a bacterial disease that is transmitted by the Asian Citrus Psyllid. Originating in China, this insect pest is small and brown, with a slight marbling color to its wings. The Psyllid is spread by strong winds, making hurricanes a nightmare for citrus producing regions. Once the citrus tree is infested by the Psyllid, the insect moves throughout the tree feeding on the fruit tree’s leaves and stems; all the while, infecting the tree with Citrus Greening.

Trees infected with Citrus Greening present with symptoms of yellowing shoots, small bitter misshaped fruits, discolored leaves, and a visible white wax substance. This waxy substance is left behind by the Psyllid. Eventually, the entire canopy will turn yellow and the tree will die. There is no cure for Citrus Greening, and once a tree, or crop, has become infected the only solution is to remove the infected plants.

The Effects of Citrus Greening on Crops

In just 10 short years, the Asian Citrus Psyllid spread its fatal disease throughout Florida and at an alarming rate. With just four citrus producing counties reporting the disease in 2005 to every producing county being infected by 2015. The magnitude of infestation and destruction to the citrus crops is difficult to fathom. A report in 2018 by the Florida Department of Citrus, showed that Florida had a total of 98 million citrus trees; when recounted in 2017, this number had experienced a significant decrease with the number dropping to just 62 million.

Following hurricane Irma, times have continued to become increasingly difficult for Florida’s citrus farmers as production costs per acre have double, and even tripled for some. Meanwhile, crops are producing a third of what they once did, and the quality is not as good. Bill Roe, the Vice President of his family owned citrus farm, commented on Florida’s oranges during an interview with NBC News stating:

“For anyone who wants to advertise 100 percent Florida orange juice, it’s virtually a thing of the past”

He went on to add that imports are being used to make up the difference, due to the decline in the overall quality and quantity of oranges being produced in Florida. In fact, from 2017 to ’18, Florida only produced enough citrus fruit to fill 45 million boxes. Although this may sound like a lot, this is the lowest production to come out of Florida in 75 years.

Protecting Crops against Citrus Greening

With no cure for Citrus Greening, growers have been left with no choice but to remove and replant infected trees and crops. Unfortunately, due to rising costs this has not been a realistic option for many citrus farmers, and they have been forced to sell their land. Citrus Greening has also had a significant impact on Florida’s agricultural economy. As over the course of just 4 years, Florida experienced a 32% decline in industry related employment.

After having spent years combating these disease carrying insects, all the while desperately seeking solutions to protect their crops and livelihoods against Citrus Greening, growers have shifted their focus towards the future and prevention. There are currently two effective products on the market for citrus growers that, though slightly different, are very similar in nature and have had promising results.

Individual tree nets

When citrus grower, Tommy Thayer, was looking for a solution to defend his crops against Citrus Greening, he found there were no solutions available. So, he partnered with Scott Thompson to invent their own. They call their invention The Tree Defender; which is a netted bag that is placed over each tree providing protection for up to 2 years. University of Florida Scientists researched this product and their findings revealed that trees were in fact protected from the Asian Citrus Psyllid, and that the citrus trees also grew better.

Protective Screens

With Citrus Greening have such detrimental impacts on the citrus industry, the use of protective screens has become the new norm for planting and growing citrus plants and trees. This technique is known as (CUPS) citrus under protective screening. The screened structure is made from galvanized steel and anti-insect mesh and it is large enough to cover 20 acres, within 2 structures. This mesh structure provides the citrus crops with protection from the Asian Citrus Psyllid, as well as, other insect pests and winds up to 80 mph. Trees planted and grown within these protected environments actually grow and produce the fruit faster. Ed Pines is the engineer behind this concept, that he heard from Scientists with UF/IFAS. Once this idea took off, he then established Precision Citrus LLC, to construct these magnificent structures for other citrus growers.

Although Citrus Greening remains a huge issue for Florida’s citrus farmers, these new innovations bring hope for the citrus industry.