By adhering to the following seven steps, growers will best be able to deal with the presence of the disease in their individual groves and in the industry, collectively. If all growers follow these seven simple steps we should be able to slow down the disease from spreading from tree to tree or from grove to grove and so reduce the impact that this devastating disease could otherwise have on citrus production in Belize. Remember that there is no cure once a tree is infected and all citrus varieties are susceptible to the disease.
1. Get Training To Recognize Syptoms2. Regularly Scout For Disease Symptoms
Getting used to what the symptoms of the disease look like may take some time but once you get used to how they look it is relatively straight forward. If necessary, growers should contact CREI staff for help on recognizing what symptoms for greening look like. CREI staff can train your farm captains or your staff and if you have internet access there is good training course from the University of Florida at: www.citrusgreeningtraining.com.
Growers should walk through their groves, or hire staff to walk through their groves, from tree to tree looking for symptoms of the disease. This should happen each month or at least once every three months. Branches with suspected leaves should be tagged and leaf samples removed to take to a member of CREI staff who will be able to confirm whether or not the symptoms are in fact HLB greening and help you get a test done at the CREI lab if there is any doubt.
3. Take Suspected Leaf Samples To CREI Lab
If there is any doubt as to whether a leaf symptom is in fact citrus greening disease the CREI staff can now conduct a test for the disease in the CREI lab using suspect leaves or the insect vector (the Asian Citrus Psyllid) collected from the grove. There is currently no charge for running tests but the cost is about Bz$10 per sample. Growers should complete the necessary forms and the results will be available for you within (2)two days.
4. Infected Trees Must Be Sprayed With Insecticide, Cut Down & Burnt
Trees found to be infected with the greening disease must be sprayed with broad spectrum insecticide, cut down and burnt. The application of insecticide is required to make sure that any of the Asian Citrus Psyllids (ACP), The insect that spreads citrus greening, that maybe on an infected tree are killed before they have a chance to fly to neighboring trees and spread the disease further in the grove. Next the infected trees should be cut down and burnt. An application of herbicide should be made to the cut trunk to prevent sprouts emerging from the cut trunk or the roots.
5. Monitor & Control Asian Citrus Psyllid (ACP) Populations
Growers should monitor the populations of the ACP in their grove using the stem tap method. This is done by holding a piece of white paper on a piece of board under a branch on tree and by tapping the branch three times. The number of psyllids and other insects that fall onto the paper should then be counted. This should be done 10 times in 10 locations in the grove each week and the number of insects found recorded. If growers do this on a regular basis they will get a good idea of how the populations of insects in their groves vary during the year and they will notice how flushing patterns in the grove influence insect populations. Growers can then consider applications of foliar insecticides but only when there is no leaf or flower flush taking place in the grove. When growers see high populations of ACP feeding on young leaf flush this is not a good time to spray. This might seem like strange advice but the reason is that at times of high ACP population insects that are beneficial to the grower, as they do not harm citrus but control the ACP and other pests, will also be found in the grove. If growers spray at this time they will kill these beneficial insects and allow populations of ACP and other harmful insects to increase still further. Systemic insecticides like Confidor, should be used on young plants.
6. Only Use Plants From Nurseries That Are Screened & B.A.H.A. Approved
Only Use Plants in the Grove from Nurseries that are Screened with BAHA approved structures. CGA/CREI does not currently recommend growers to plant citrus as there is a possibility that all citrus plants in Belize could be infected with citrus greening. CREI will be working with nursery owners to produce greening-free plants.
7. Only Plant Young Plants In The Grove If Greening Incidence Is Low
Only plant young plants in the grove if there is a low to no incidence of greening in the grove. Growers who plant young plants in their groves where citrus greening is present in the mature trees are likely to be wasting their money. The vigorous flushing of young trees will attract populations of ACP to the plants – if the young plants become infected with HLB-greening experience from Florida suggests that the trees will be dead within 1.5 to 2 years. Young trees in a grove should be treated with systemic insecticides up to the age of three years. Systemic pesticides when used correctly (Trunk & Drench application) is substantially more effective than using as a foliar application. One very important factor that should be permanently engraved into our minds is the negative effects the pesticide applications can possibly have on the natural enemies of the citrus psyllids. The active ingredient Imidacloprid is found within a range of product brand names, this is vital information, knowing the Active Ingredient (AI) will reduce the potential risk of resistance.