Having nutrition problems, or some sort of disease has set in. This condition is affecting seven of my mature twelve trees, including Valencia, Pink grapefruit, Satsuma, Ruby Red, Temple, Thompson, and Meyer. Trees have been healthy since planted some 12 years ago. Sandy soil.
Pruned in January (do this every year), fertilized with a citrus-specific fertilizer, and Ironite. Noticed then a grainy texture to the leaves, which continues to worsen. Applied manganese a few weeks ago – no change. Applied a foliar feed with micros – no change. In fact, the tops of my trees are gradually turning chartreuse – they are completely losing the normal solid green color. The trees have set new fruit normally. Finally, we are having a mild drought in northeast Florida, so I have been slow-watering the trees with a soaker hose once a week. Very concerned about the color of the leaves turning light green – presume there is a nutrient deficiency at play, but can’t identify it. Or, is this a disease of some sort? Can someone help?
[img]http://img69.imageshack.us/i/citrusdeficiency.jpg/ [/img]

It is spider mite.

Without a good clear close-up picture of the leaves in question, no one can give you any type of a knowledgeable answer. If you supply a picture, someone on this forum should be able to help you. Because you live in Florida, you can also ask your county agent. A county agent in Florida should well know about problems affecting citrus. - Millet ( 631)

Phil,

Judging by the picture, I think it does look like spider mite infestation. Inspect reverse side of leaves, preferably with a magnifying glass. Do not wait! Dry weather is favorable for spider mites... I was fighting them since mid March.

Good luck!

Got the 18X jeweler's loop out and looked closely at the underside of a leaf and there are little brown bugs crawling around. They are too small to positively identify in the light of an incandescent bulb, but they are round shaped. I'll look again tomorrow in the bright sunlight. Also, saw some white stuff - maybe eggs? Not glad to have the pests, but very happy to know what is causing the grainy texture and light color. Two questions for now: 1. What is the best course of action? and 2. Will the solid color return after the mites are eradicated?

Also, I tried and tried to attach a photo to my post but couldn't figure it out - so I included the URL to ImageShack. If there is a way to insert a picture, please let me know.

Finally, thanks folks, for your help.

I see where Millet said in another post discussing spider mite eradication using oil: "UltraFine is 100 percent non toxic, and 100 percent effective." Volk was also mentioned. Can someone give me more information on these products? I am a dooryard grower so don't need to mix up 500 gallons. Is this a product I can buy at Lowes, Home Depot, Ace, or another supplier? I am much encouraged by the aspect of "...100 percent effective." I would think a complete drench, including leaves, stems, limbs, and trunk would be called for. Right? BTW, the second flush is just starting.

Darkman,

You are right regarding the humidity... However, they attack in spring and fall when humidity is still low. Btw, we have the same climate.

Phil,

I am afraid the damaged leaves will stay damaged and may eventually drop. Please, experts, correct me as I really hope of being wrong on this!

Be careful with oil sprais as they are not recommended for temperatures above 85 (at least, I learned this for neems). What worked for me was lime sulfur spray... It is also not recommended for over 85-90 but applying it in late afternoon should be fine. It took me two-three applications to get rid of nasties and neems oil had no effect at all... To my surprise.

One more thing: act quickly as they may cause quite damage.

Good luck!

Sorry, I did not see the link at the bottom of Phil's post for the pictures of his tree. Guess I must be going blind. GT is correct about spraying at temperatures above 85F. When using Volk or UltraFine oils, either spray in the early morning or at dusk. Being an oil they restrict transpiration for a short time. However both oils are extremely pure and are rapidly volitale, therefore they evaporate from the plant quickly, before the heat of the day. Volk oil was invented especially for citrus. You should be able to find either the Volk or Ultra Fine in quarts at Home Depot, Lowes or most good garden centers. Spray both the upper and lowers leaf surface. Works very well. - Millet (630-)

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Is it true that Imidacloprid will not kill spider mites?