Huanglongbing (HLB), commonly known as citrus greening disease, was first detected in Texas in 2012 and has since spread to 17 counties across the southern portion of the state. Florida has already lost more than US$4 billion in their economy since the disease was first detected in Miami-Dade County in 2005. Texas is actively trying to prevent the spread of citrus greening disease and does not want to suffer losses similar to Florida.

Trees can be infected with the disease for years without showing symptoms. The Asian citrus psyllid, which spreads HLB to trees it feeds on, was first reported in Texas in 2001. Today, the quarantine for the Asian citrus psyllid covers the whole state. You can learn more about HLB by clicking here.

The Rio Grande Valley

While Texas’s citrus industry makes up less than 5 percent of the United States’ citrus production, it is still worth US$100 million and is an important industry in South Texas, particularly in the Rio Grande Valley. This area grows the majority of Texas’s citrus and is comprised of four counties: Hidalgo, Cameron, Starr and Willacy.

Just 10 miles north of the Mexico-Texas border, in Hidalgo County, lies the town of San Juan. In January 2012, a 5-mile radius emergency quarantine was established around infected trees in San Juan. The officials in the Valley tried containing the disease, but by the end of 2014, Cameron, Fort Bend, Harris, Hidalgo, Montgomery and Willacy counties were under the HLB quarantine. Infected trees in Fort Bend, Harris and Montgomery County were found to have been bought in the Valley.

In the Valley in 2014, there were 430 reported trees infected with HLB. By 2016, that number had more than tripled, rising to 1,700 and included trees in Houston, Fort Bend and Montgomery counties.

Tamarixia Radiate Wasps

One way officials have tried to control the spread of HLB and the Asian citrus psyllid, is by using a parasite. Tamarixia radiate, an Asian wasp, has also been used in Florida and California to kill the Asian citrus psyllid. The female adult wasp lays her eggs under Asian citrus psyllid nymphs. The nymphs are not yet able to fly, so when the wasp’s eggs hatch, they feed on the hemolymph of the nymphs. Adult wasps also like to feed on hemolymph (bodily fluids of the nymph) and the excess sap the nymphs excrete.

Bright, Plastic Triangles

Texas officials deployed the use of bright, plastic triangles in the fall of 2019, to attempt to control the population of the Asian citrus psyllid. These triangles are brightly colored to attract the psyllid and have “contact insecticide”. Once the psyllid lands on the triangle, they are killed. Promising results have been received from the citrus grove trials of these triangles and this form of controlling the Asian citrus psyllid could one day even be deployed by homeowners.

Plant It Where You Buy It

So what does this mean for the everyday Texan who owns or wants to buy a citrus tree? First and foremost, be proactive. Routinely check your citrus trees for signs of disease or the Asian citrus psyllid. If you are planning to purchase a tree, do your best to give it a good look over for the same signs. Citrus trees are still available for purchase from nurseries, but they must remain in the county they are bought in. Do your part in helping stop the spread of citrus greening disease in Texas and make sure you are not transporting trees across county lines. For those who share or sell fruit from your home trees, you’re in luck! Fruit can still be moved freely, however any leaves or stems attached to or on it, must be removed before transporting.

HLB Continues to Spread

In 2018, three more counties were added to the growing list of counties under the citrus greening quarantine. By the end of 2019, six more counties had been added to the listing. The HLB quarantine has almost completely engulfed the Coastal Bend, Gulf Coast, and area in and around the Valley.

Texans are serious about fighting this disease, going as far as to perform door-to-door, backyard checks on residential trees. MitoGrow, a Houston-based company, has joined this fight. You can read more about our efforts to help stop the spread of the Texas citrus greening disease problem by clicking here.

For further information on the topics discussed above, check out our main sources for this post:

  1. Citrus Greening Keeps Spreading in Texas
  2. Tamarixia Radiate Wasp
  3. Progression of Citrus Greening Disease in Texas
  4. USDA Citrus Fruits 2018 Summary