there’s a serious disease you need to know about affecting all citrus cultivars and can cause a rapid decline in the health of trees Citrus greening is caused by a bacterium that is spread by a psyllid insect As the psyllid feeds on the sap of a citrus tree the bacterium can move throughout the plant This means that the infection is systemic throughout the plant and cannot be removed by pruning off the portion expressing symptoms An early symptom of citrus greening is the yellowing of leaves that may appear on a single shoot or branch leaves may have a mottled or blotchy appearance Affected trees can also have twig dieback and rapidly decline into a non-productive state within 2 to 3 years In trees with advanced stages of the disease abnormal in appearance and fail to color properly The Asian citrus psyllid is the vector for citrus greening the psyllids remain capable of transmitting citrus greening for their entire lives The psyllids feed and survive primarily on citrus and citrus relatives.   Citrus greening is one of a few citrus diseases that can be considered a truly limiting factor for citrus production Control is difficult if infected trees are widespread and the psyllid vector is well established The greening bacterium can infect virtually all citrus species as well as several citrus relatives that are grown as ornamentals such as orange boxwood (Severinia buxifolia) and orange jasmine (Murraya paniculata) In addition to being a host for the bacterium they are also a host for the Asian citrus psyllid having these ornamentals in the landscape can allow psyllid populations to build up and increase the risk of spreading the disease to other ornamental and citrus plants Movement of these ornamentals is restricted under Florida regulations and they should not be moved out of areas where greening is present Now for a little good news in the fight against citrus greening Homeowners who are growing citrus trees can now apply online for some parasitoid wasps to release on their citrus tree will hunt the Asian citrus psyllid and parasitize the young psyllids An egg is laid in the psyllid where hatches More information on Tamarixia can be found at http://edis.ifas.ufl.edu/in858 the spread of citrus greening could be reduced or possibly stopped The Tamarixia release program is just one of several tools researchers and growers are using to slow the spread of greening Tamarixia releases should work well in urban areas where the wasps can fly from tree to tree throughout a neighborhood Now for some additional steps that you can take to protect your trees from citrus greening 1)      Check your citrus trees for leaves that show a blotchy This appears as a variegated yellowing of the leaf that is not symmetrical (or a mirror image) on both sides of the leaf’s center vein An easy test to help determine if the symptoms are symmetrical is to draw two circles on the leaf surface on either side of the center vein.  If the areas within the two circles look similar that would rule out citrus greening and indicate a minor element deficiency An advanced symptom is typified by bright yellow leaf veins that are raised 2)      If a tree does have citrus greening The reason for grinding up the trunk is to prevent the production of root suckers 3)      Orange jasmine (Murraya paniculata) and orange boxwood (Severinia buxifolia) plants should be removed since they allow the bacterium and psyllids to multiply 4)      Get the soil tested unless a soil test has been done within the last two years before fertilizing can begin again in October For information on soil testing for your citrus tree 5)      For extra protection Neptune’s Harvest) on the foliage of your citrus tree Use a hand pump-up sprayer to apply a fine mist on both sides of the foliage 6)      Re-mineralize your soil with rock powder (i.e etc.) to provide important trace elements for a healthier tree and more nutritious fruit there are still steps that can be taken to grow your own home-grown citrus. Sally Scalera is an urban horticulture agent and master gardener coordinator for the University of Florida’s Institute of Food and Agriculture Sciences.  To apply for some Tamarixia, follow this link