. . . . "Host Plant Resistance Although there is no real resistance in Citrus spp. to citrus greening disease, some species and cultivars are somewhat tolerant. Koizumi et al. (1993) did extensive field surveys showing that some cultivars were less susceptible to decline than others. Most of the sweet orange trees became infected with the pathogen and subsequently declined, while grapefruit was more tolerant. In general, sweet oranges, mandarins and tangelos are most susceptible, grapefruit and lemon are more resistant, and limes, Poncirus trifoliata and citranges are the most tolerant (Lee 1996). Cultural Control Management of citrus greening in areas where the disease is endemic depends largely upon cultural control. Infected limbs and trees should be removed as symptoms appear. The pathogen apparently moves fairly slowly within the plant after infection, so severe pruning can be helpful. For African greening, Buitendag & von Broembsen (1993) make the following recommendations: If the infected tree is 5 years old or less, remove the tree. If it is between 6 and 10 years, remove it if it is 75% infected; otherwise remove branches. If it is more than 10 years old, remove affected branches up to 40% of the tree. Do not plant young resets in old groves affected by greening. The tendency for suckers that sprout after pruning to be infected with greening depends upon the diameter of the branches. Branches 10-19 mm in diameter grew no suckers. Among branches 20 mm in diameter or more, the smallest ones were most likely to produce infected suckers (86% for branches 20-29 mm, as compared with 29% for those that were 40-60 mm) (van Vuuren 1993). Roistacher (1996) cited a Chinese program for rehabilitation of citrus in Fujian Province in which cultural control played a major part. Windbreaks were established to protect plants from psyllid vectors (although the efficacy of barriers for protection from a persistently transmitted pathogen is questionable). Trees were examined regularly for citrus greening disease, and all infected trees were immediately removed and replaced with healthy trees from a certified citrus stock program at the Fujian Academy of Agricultural Sciences (Ke & Xu 1990). In another Chinese program, part of the control program involved hand-removal of summer flush in high density citrus plantings following rice cultivation (Aubert 1990b). " Here is a link that might be useful: Some tolerances to citrus greening

I can't figure out how to post pictures but the picture of citrus canker on leaves of a citrus tree on wikipedia is what the leaves that I removed from my tree looked like. One of the leaves was also dripping this clear sticky liquid. The liquid came from one of the infected leaves and splashed onto three of the other leafs. I am leaving these leaves on the tree to see if they develop the same lesion type things that were on the leaf that dripped on them. (I have gone over this tree with a magnifying glass and have not seen any bugs so I am sure that the clear sticky stuff is from whatever disease my tree has.) The good thing is that the treeÂs health is not spiraling down as fast as it was before I removed the damaged leaves and the dying branches so hopefully it will perk up and start growing. If it is citrus canker then I guess it wont matter if it starts getting better because it will be taken away from me anyway. :( hopefulauthor- Thanks for the advice. I moved my tangerine tree to a different room away from all of my plants. I am hoping that it isn't to little to late since the tree has been dripping stuff that could infect my other trees. Sarah

more photos...

Citrus leaf miner is not much of a concern on large citrus trees. However, on small young trees the miner does cause quite a stress on the tree . Most commercial growers don't bother with controlling the insect on large producing trees.