https://www.growingproduce.com/citrus/insect-disease-update/can-citrus-greening-beaten-biological-approach/

Nitrogen is available at most all pH levels, from as high as 9.4 all the way down to 4.  Nitrogen's greatest availability is between a pH of 8.5 and5.5.

Luak , that would work also.  Are the trees turning color yet in Eureka Springs?

The choice of branches to eliminate from a citrus tree is based on the concept that any space within the canopy must be covered by only ONE branch.  It is unwise to let surplus branches occupy the same aerial space.  Anyway, thinning must not deplete any canopy sector. Suckers can only be kept if they occupy free spaces. After a few years they bear fruit, but all interior suckers MUST BE CUT OUT.  A harmonious citrus tree grows to an almost round shape (globe). Vegetation free canopy spaces must be avoided since they reduce yield.

According to the Spinosad General Fact Sheet of the National Pesticide Information Center, “Spinosad is a natural substance made by a soil bacterium that can be toxic to insects. It is a mixture of two chemicals called spinosyn A and spinosyn D. It is used to control a wide variety of pests. These include thrips, leaf miners, spider mites, mosquitoes, ants, fruit flies and others.” It is approved for use on organic gardens by Organic Materials Review Institute, or OMRI. One caution with its use: In high concentrations, it can be toxic to honey and native bees, so we should only spray when bees are not present on our trees.

Actually, looking at the picture, that half of the tree looks to be very old and  dead,the bark has begun to fall off.  Is there any growth at all on that portion of the tree?

Breeding and growing citrus from seed to prevent HLB

https://www.youtube.com/watch?v=f-g6bcX88Eg&feature=youtu.be

High concentrations of NATURAL gibberellins are associated with the juvenile phases of citrus development. GA3, the most commercial used forum of the hormone, has shown stimulation of budbreak and vegetative shoot growth, but inhibits the transition from vegetative to reproductive flowering growth in citrus if applied prior to irreversible commitment to flowering, but it does not affect flowering when applied after irreversible commitment to floral development. GA3 also prevents senescence in citrus and can  maintain chloroplast thus keeping citrus fruit green longer. Lastly, GA3 is sprayed prior to harvest time to delay rind senescence so that treated fruit remain physiologically young for a longer period of time, improving on tree storage and extending harvest.

Its long been known that water stress of a citrus tree can make the tree flower.  It is done all the time with lemons.  However, I doubt that an application of potassium nitrate has much to do with flowering.

Dr. Manners once wrote that the reason that zygotic gametes loose out against nucellar is that the zygotic gametes began growing later than the nucellar.  Thus the nucellar have a head start and crowd out the zygotic.

My Cara Cara fruit mature from  middle/late November through February.   Cara Cara hangs well on the tree.

Brian, for new grafters I think you will have good success with cleft grafting,  Just make sure the stock and scion are about the same size is with.

HardyVermont,  I have never seen (other than your post) where HO cannot be applied until 6 weeks since last application.  I do not know the purity of Southern Ag's HO product as I have never purchased the product, Perhaps that is the reason for their caution..  I use Ultra Pure HO, which is the most purified  HO on the market.  I have spayed it for years and years  several times in the same week, specially when a tree is flushing new growth, so that the leaves do not develop all twisted and deformed from aphids, and thrips feeding on them,.  I just don't care for the smell of neem, particularly when spraying inside a greenhouse or home.   By the way, it is GREAT seeing you on the forum.