This column focuses on ” citrus greening” disease, submitted by John Gose, Lykes Bros., President of Highlands County Citrus Growers Association.
I would like to dedicate this column to Huanglongbing (HLB), Citrus Greening. In a recent Flatwoods Citrus news letter Dr. Mongi Zekri asked several questions. What are growers waiting for to take Greening seriously? Why are citrus growers waiting to inspect their groves for Greening? What are growers waiting for to remove positive Greening infected trees? These are valid questions due to the realism that the majority of citrus growers are not inspecting groves for Greening and it seems as if growers are waiting for the inevitable to affect them before they act.
Letâ€™s take each of these questions and address them one at a time. Waiting to take Greening seriously will be a fatal mistake in that once Greening is detected in your grove in the Yellow Dragon stages it will be too late. Everyone must understand that this disease is not something you can spray for once you have infection. It is not like having a high population of Rust Mites, Spider Mites, PFD or Brown Rot. These problems can be addressed through spray applications and can be brought under control over a reasonable amount of time. Greening on the other hand is not problem you can react to once symptoms occur. We must be proactive and scout the grove on a regular basis to stay on top of it.
Scouting groves is critical for success against this disease. Once even 10% of your trees show visual symptoms it will be too late. I will use an example of a large grove in south Florida that when Greening was first detected they had 10% of their trees showing visual symptoms in February of 2006. They started a tree removal strategy along with sprays to control Psyllids but in August or September of 2006 they were experiencing 60% of the trees showing visual symptoms. With a rate of spread like this you can figure out how they feel about the remaining 40% of the trees. Yes, the majority of them are probably infected and it is just a matter of time before they show symptoms. The goal with scouting is to find the disease symptoms in the beginning stages. This is going to be very difficult due to the fact that just about every grove in the state has yellowing limbs or sections of limbs which are caused by a variety of reasons. It will take time for inspectors to understand exactly what they are looking for and we need to be prepared to spend a lot of time in the grove looking and training. I encourage growers to stay informed on training offered by I.F.A.S. or D.P.I. and make sure your employees performing scouting activities attend as many as possible. The best time for scouting is after the fall flush has hardened off and prior to the spring flushes emerging. Right now is one of the best times of the year for scouting and we all must get inspectors in the field. Once Greening is detected scouts must also inspect for Psyllid populations in the areas with positive Greening so spray applications can be adjusted for control.
The removal of infected trees is also critical in the battle against Greening. It will be difficult to make it mandatory for positive tree removal how ever this is something we need to address. I think most growers will not have a problem removing a tree with Yellow Dragon type symptoms. The problem will be removing a tree with a small area of Greening symptoms while the remainder of the tree is loaded with fruit. Believe it or not we have growers in the state that feel they can bring these trees back through nutritional applications and are not removing trees. History of Greening in others countries shows these growers will not have a grove within five years and in the mean time they are infecting their neighbors. Tree removal regardless of severity should not be an option for growers. I think the more growers are educated on the disease the willingness to remove trees will be easier.
Greening will be difficult and expensive to manage. We will need more employees to conduct scouting activities, addition materials in spray application and additional spending to remove infected trees. For citrus growers in this business for the long haul inspections, additional sprays and timely infected tree removal will be a must in order to remain in business. I encourage growers to train your employees on a regular schedule and gain as much information that you can concerning Greening. Executive Director Ray Royce has posted a link on the H.C.C.G.A. web site to help us stay updated on Greening. Please use this resource and take advantage of the information your association is providing. We might be able to schedule some training at the Ag-Center and we will look into that.
Remember, Greening positive Psyllids have been found in Highlands and Polk counties. It is just a matter of time before positive trees start showing up and when that occurs it may be too late for some of us.