The Tropical Fruit Forum

Ilya11 thank you for the Okitsu, Japan Horticultural Research Station article.  Interesting reading.

Looks like sun burn.  The problem was that the tree's needed to be brought into the direct sun light slowly,by first putting them in shade, and gradually moving into direct sunlight a little at a time.  Like DWF Citrus wrote, cover the trees with some type of shade cloth.  I don't know if the burnt leave will re-green, but with care the new growth should be OK.

I picked my last two Dekopon fruit today.  Since the variety is alternate bearing, next years crop should be a small crop. Guess I need a second Dekopon tree in order to get a good crop every year.

The odds of a mutant must be every slim, taking many many many  seed germinations.

A Florida nursery, Southern Gardens Citrus Nursery, is proposing the release of a GM virus, Citrus tristeza virus, which has been engineered to express bacteria-fighting proteins found in spinach. The GM virus, which has been undergoing controlled field tests since 2010, would be grafted -- not sprayed -- onto citrus trees in Florida. USDA has announced its intent to launch an environmental impact statement on Southern Garden's proposal

Some companies market their food product as “non-GMO” to create a nonexistent distinction that gives them a competitive advantage (sometimes at a premium price). For example, Tropicana Orange Juice includes the “Non-GMO Project” seal on its package, yet its sole ingredient is oranges, and there are no commercially grown, genetically engineered oranges. Every brand of orange juice is naturally “non-GMO,” provided the only ingredient is oranges.

https://www.geneticliteracyproject.org/2017/04/21/no-gm-oranges-tropicana-deceiving-consumers-non-gmo-label/#.WPpNlkqWIip.twitter

Ponderosa lemons taste much like a  Eureka /Lisbon lemons.  The fruit of the New Zealand lemonade tree can be eaten in hand directly off the tree,  They taste pretty much like lemonade.

In 10 years, Florida's round orange production fell from an average 342 boxes per acre down to 163 boxes per acre. That is a 52% reduction.
The report also noted break-even or negative cash flow groves are selling at discounted prices. The University of Florida benchmarks the typical all-in production costs for processed oranges is $2,235 per acre. Given that, the break-even number for a grove would be 225 boxes per acre receiving $2.28 per pound solids delivered (assuming 5.86 pound solids per box).

http://www.freshplaza.com/article/174155/Retail-prices-for-Floridian-orchards-shows-grim-picture

Really not sure of the maturity time for Flying Dragon.  Flying Dragon is of course a slow growing tree.   I have four two year old FD trees growing at this time that are 2-ft. tall that have not yet flowered.  My guess is at least 5+ years to begin fruiting.

Mainly Citrus spp., at least two species of Murraya, and at least three other genera, all in the family Rutaceae.

If they were actually determined to have HLB I think the trees would have quickly been removed.

Not sure if your leaf symptoms are showing symptoms of greening.  Yellow veins is common in nitrogen deficiencies, but the balance of the leaves shown on your link are still very dark green, so at this point that rules out nitrogen deficiency.  Citrus greening symptoms normally show a more blotchy appearance.  Another greening symptom is what is normally called "corky veins".  I'm not sure what "corky veins" looks like, perhaps you can find that out on the Internet. 

gozp, the deficiency your leaves are showing is manganese, not iron.  At this time of year these "transient" Manganese deficiency symptoms are VERY common.   These transient symptoms are due to a marginal supply of available manganese in the soil, which the tree roots temporarily are unable to extract enough Manganese to supply the large rapidly growing new flush of leaf growth.  Normally the leaves will return to the normal dark green color as the grow flush ends, and the roots are able to once again catch up.  However, you can apply a manganese spray such as Southern Ag Nutritional spray if you wish, or in most cases simply do nothing.   In the rare event that the leaves still look deficient upon the completion of the flush, there is always time to apply manganese.