by Deborah Birge, Fort Bend County Master Gardener
Besides being hot and miserable, July held a wake-up moment for Fort Bend County citrus growers. Citrus Greening Disease or Huanglongbing, was identified in a tree growing in a Harris Country retail nursery resulting in a quarantine for the entire county. Just this week, the quarantine has been extended to include Montgomery and Fort Bend County.
But what is Citrus Greening? CG is a bacterium injected into your tree via a very small insect called the Asian Citrus Psyllid. The disease received its name because the mature fruit on infected trees fail to turn orange and stay a greenish coloration. There is no cure for this disease resulting in the death of your tree within a few years. Symp-toms are varied ranging from a single limb showing yellow leaves and dieback, to lopsided and bitter fruit. Most importantly, many of the citrus greening symptoms look like the symptoms of nutritional deficiencies. Confirmation of citrus greening is only through laboratory testing. You can learn more about the signs of CG by using this website – www.texascitrusgreening.org/
Citrus Greening entered the US via Florida in 2005 causing widespread damage to the commercial citrus industry. Since then, Louisiana, California, South Carolina, Georgia and now, Texas have been added to the CG roster. Interestingly enough, our invasion did not come from Florida or California, but Mexico. The first identification was in San Juan in Hidalgo County in 2012, the second in Gonzales, then Harris County in August, 2014. CG is a fast moving disease causing immense destruction to the citrus industry. It is important that everyone, home growers as well as professional growers, work toward reducing the numbers of the Asian Citrus Psyllid. The Texas Department of Agriculture website can provide ongoing information concerning the quarantine at http://www.texasagriculture.gov.
So, what does the quarantine mean to the Fort Bend County citrus grower? Most importantly, you must not purchase citrus plants from any retail facility within Harris County, Fort Bend County, or Montgomery County with the intent to take it outside of the quarantined area. It’s perfectly safe to purchase citrus from any retail facility in or out of these listed counties but, once you cross back into the quarantined area, the plant should not be moved outside the county boundaries again.
At home, be on the lookout for the CG vector, the Asian Citrus Psyllid. This psyllid is very small, averaging ¼ inch but can be found mainly on the new growth of your plant. They lay their eggs on the underside of the leaf leaving a waxy substance. Psyllid hunting is best in the early morning using a sheet of copier paper and a pencil. Angle the paper under a group of leaves then thump the branch sharply with the pencil. Any hidden psyllids will fall onto the sheet. A good website for psyllid identification is http://www.saveourcitrus.org/
No psyllids? Lucky you! Do check your trees on a regular basis, once a week or so. Remember that psyllids are not everywhere so it’s okay if you don’t have them. And, remember even if you do find psyllids, it doesn’t mean you have CG. Not all psyllids are infected with CG. But, if you find psyllid eggs, larvae, or adult insects, it would be prudent to begin a spraying program to reduce their numbers helping to prevent your plants from being infected. Psyllids can infest a citrus tree throughout the year and may re-infest trees day, weeks or months after you have sprayed. An effective year-round control requires utilizing multiple control materials such as oils, soaps, neem products and kaolin clay products.
The following links will offer information on controlling the Asian Citrus Psyllid.
Citrus greening information