My Satsuma has had a few leaves like this for a while, but recently a lot have turned like this.  The central vein turns yellow, while the rest of the leaf is green.  Then the yellow spreads outward and the leaf drops.  I was thinking just Nitrogen deficiency, so I just sprayed with fish emulsion.  Could it be something else? 

Over the Summer, I had a pretty bad spider mite problem.  I thought that might be why the leaves are mostly smaller, cupped and pointed upward.  Could this causing the vein yellowing now? 

Only things I sprayed in the past have been dormant oil, micro nutrient spray and fish emulsion.

My Valencia orange is covered in fruitlets just dropping the flower petals.  I've read that I need to thin the fruitlets about now to prevent alternate bearing.  But how much to thin?  50%?  75%?  More?

Do you pick off the smaller ones or the larger ones that are a little older?

What do you guys do to prevent alternate bearing?

Genetically modified trees symptom free after 3 years surrounded by infected trees.  They used genes from a mustard plant.

http://news.ufl.edu/articles/2015/11/uf-creates-trees-with-enhanced-resistance-to-greening.php

I have a small Glen navel orange tree with some kind of boring insect.  There are two holes pretty close together with curly strands of sap coming out.  What should I do?

My lights finally came in.  I haven't got everything set up yet.  I went with three fluorescent fixtures that have twelve t-5 bulbs per fixture.  The fixtures are rated for 60,000 lumens each.  One is set up with only 6500k "blue" lights, another has only 2700k "red" lights, and the fixture between them has half and half "blue" and "red".  I think I might end up turning the fixtures and bringing them closer together, so the light overlaps better.  I plan on enclosing the area with white walls and putting down white plastic on the floors.  I picked up a digital meat thermometer and already have a fan and heater for the area. 

11ft tall - How old is your tree?  Do you know what rootstock it's on?

I just picked up a Cara Cara from Harris, but it's really tiny.

I looked into this a few months ago and didn't get very far.  You can basically get Sugarloaf, White Jade, Smooth Cayenne, Florida Special, and Elite Gold from a few nurseries, but that's really it.  I emailed everyone I could get ahold of including commercial research groups, propagation companies in Cuba and France and growers in Brazil.  And basically, in the US, you have to get anything rare from ARS GRIN.  There is a slim chance you could find something odd from one of the Caribbean islands at a farmers market in South Florida, but it probably would be hard to know what specific variety you had.

I did get ahold of a few guys who have requested rare pineapples from GRIN and they recommended sticking with MD-2, because it is so superior to the other varieties.  Still, I'd like to grow some of the odd stuff just for something different.

 

Is anybody using grow lights on their container citrus over the winter? 

How do you know what size lights to use?  Or what type?  It seems like there are a dizzying array of sizes, types, and prices.  I can apparently spend $5 on a LED screw-in light bulb all the way up to $1,500 on a big LED lamp that hangs from the ceiling.  There are also Metal Halide (MH) bulbs and High Pressure Sodium (HPS) bulbs.  Is there a good source of info on this for use on citrus plants? 

Instead of putting my plants in the ground this Fall, I am thinking about keeping them potted and indoors at my shop near the windows with grow lights (and heaters) over the Winter.  Would this would help them add some size before the Spring?  My new plants from Harris and Four Winds are really tiny.

Added new pictures.

While searching online for different mandarin and orange trees to try, I saw quite a few pictures of citrus trees from China trimmed like vertical cylinders and totally covered in fruit. 



While I find these trees unattractive, trees trimmed like that would definitely let me squeeze more plants into tight places.  How in the world do they do that?  Is it just special pruning practices, a prolific inedible fruit, treating with certain plant hormones or what? 

I'll try to take a better picture, but I'm just worried about Bacterial Canker more than anything.  Is this something you guys have to fight against commonly?

Sorry for the confusing semantics.  I guess they are not all "Satsumas".  I'm still a little new to the lingo.  So, in order of approximate cold-hardiness, I'm guessing it would be something like:

HARDIER
1. Golden Nugget Satsuma (based on some anecdotal reports online)
2. Owari Satsuma
3. Xie Shan Satsuma
4. Ponkan Mandarin (mandarin x pomelo?)
5. King Tangerine?
6. Shiranui Tangor
LESS HARDY

I can't seem to find any good info on King Tangerine cold tolerance, but since it is not a Satsuma, I'm guessing it's on the less hardy side.  Right?

Groups of black spots on my Glenn mango.  Mostly on leaf petioles and some on the trunk.  They don't look raised, like bug eggs and they can be scraped off with a fingernail.

Any ideas?