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My aubergine plant seems to be developing some nutrient deficiency. I pulled it from the ground in autumn about 9 months ago and placed it into an air pruning pot with some potting mix, and kept it inside over winter. During this period it still flowered and produced several fruits which I consumed. The only issue were some spider mites which disappeared after spraying with neem oil.

I took it outside in spring after the last frosts, and it's started to flower again with fruits forming. I noticed a light aphid infestation today and sprayed with insecticidal soap. I've only fed it twice with a fish blood and bone mix, and general water with aquarium water.

I've noticed today that the older leaves are suffering with some interveinal yellowing, which seems to be starting from the middle and spreading out. Younger leaves are still green.

As aubergines go, this one is only 2 foot tall versus reaching the roof as with greenhouse grown plants.

Since the young leaves are not yet affected, is this more likely to be magnesium versus manganese or iron? pH is 7.4, and soil is moist.

the whole plant here young leaf older sick leaf

Graham Chiu
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  • Graham...have you looked at this plant closely? I think it still has spider mite. There is no getting rid of spider mite once a plant gets it they will always be there. My first look at your plant told me spider mite and then you said it had had it. I don't see the webbing, you need to take your loupe and go look closely. Sure looks like spider mite is sucking the life out of your plant. If you can find a tub to make a batch of neem turn this guy upside down and DUNK it, swish it gently is the best way. Not permanent, however. Check the neighbor plants, too. This is spider mite!! – stormy Dec 27 '16 at 23:41
  • Spray your soil with neem and check the other plants. Dunk all of them that are in pots. Then tell me what fertilizers and how much how often you've used them. – stormy Dec 27 '16 at 23:42
  • Iron availability drops at over 7.0 (pH). It looks like typical iron chlorosis. How quickly did the condition develop? – J. Musser Dec 28 '16 at 00:09
  • J. You got it the same time I did. 7.4 is too high even for plants that love alkalinity!! But to ADD iron is wrong at this point. There might be too much available once the pH is corrected. Making a soil more acidic takes a lot of time!! Easier to go the other way with lime. I KNOW there are still lots of spider mite sucking the juices out of this plant...not just iron chlorosis. – stormy Dec 28 '16 at 00:15
  • Looked with lens and no spider mites. Iron chlorosis is supposed to affect immature leaves first, and is more diffuse. I'm not sure I believe this pH meter as everything reads the same even tap water. Still looking for my pH strips to test the meter. – Graham Chiu Dec 28 '16 at 00:35
  • Just stuck this pH meter into a fresh bag of potting mix, and it reads the same. I think it's broken :( – Graham Chiu Dec 28 '16 at 00:41
  • Go find a test tube looking pH meter. Like those for aquariums. I've also got a $350 pH meter I keep testing. I kinda think 7.4 is not a bonafide result...that is quite high. Potting mixes in my experience have always been on the slightly acidic side but I always check. I've also got these duo spike meters that have shown to be very wrong too many times. I still continue to try them but never rely on them. Have you done a real soil test by a University? – stormy Dec 28 '16 at 00:50
  • I have an aquarium test kit for ammonia, nitrates etc. But can't find my pH test kit :( – Graham Chiu Dec 28 '16 at 00:51
  • What are you fertilizing with? – J. Musser Dec 28 '16 at 00:52
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    Fish blood and bone, and aquarium water – Graham Chiu Dec 28 '16 at 00:53
  • I am unbelieving that there are no spider mites on your plants. Argggghhh. Truly, there is no complete eradication, even when dunking in Neem solution. What power of lens are you using? 10X should easily show (in my case) reddish orange yellow little 'spiders' and definitely fracas or insect poop and webbing. Honest injun...you don't see any of this...look at the undersides of the leaves. I hate trying to diagnose via pictures!! Please look again? – stormy Dec 28 '16 at 00:54
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    Fertiliser http://i.imgur.com/Z5Df5Xo.jpg and npk http://i.imgur.com/isZ39li.jpg I saw these mites easily before. They're gone, and no webbing is present except for one ordinary spider web. – Graham Chiu Dec 28 '16 at 00:58
  • Fish blood and bone and poopy fish water do not a complete fertilizer make. How much and how often? Nothing else? Doesn't matter, these plants aren't getting enough and I know you have given them plenty. Need pH for sure. Do not fertilize at all until you know the pH of that soil. If that soil is garden soil...make sure most of the soil in that pot is potting soil. What does your potting soil label tell us? Different countries different everything man made... – stormy Dec 28 '16 at 00:58
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    Actually aubergines grow in aquaponic systems which use fish poopy water. – Graham Chiu Dec 28 '16 at 02:11
  • So if the soil's healthy, and the fertilizer looks good, ... possibly a virus? – J. Musser Dec 28 '16 at 02:47
  • I was being facetious, Graham, with the fish poopy water, grinning widely!! Don't you dare take it personally!!! LOL! Still looks like major spider mite damage as well as iron chlorosis. I've been dealing with lots of spider mite in my little greenhouse and until spring gets here it is constant dunking. I gave up with spraying. Spider mite is here to stay until we STERILIZE that room! Even dunking them is only a temporary respite. Blueberries need the same pH as Solanaceae plants. I have still not been able to reduce lower than 6.0. My soil was pure pumice. – stormy Dec 29 '16 at 21:49
  • Could this all be sure to the aphids? – Graham Chiu Dec 30 '16 at 23:03
  • Nope. The conditions that favor aphids is the same for spider mite. We are going on our 5th generation and still spider mite is voracious. No matter our diligent Neem dunking and spraying. When we are done with these starts we are 'fogging' the room and still will expect spider mite. What is the pH of your soil btw? I am pretty sure aquarium testers are not going to work for soil. When a plant gets weakened by sub optimal pH, temperature changes...etc. they will be great fodder for spider mite, lace wing, white fly... – stormy Jan 15 '17 at 22:43
  • @stormy I'm using soil testing pH meters and one says about 7.3, and the old one says about 7.6 – Graham Chiu Jan 15 '17 at 23:04
  • Still way too high. Have you looked at what it takes to acidify soil? You have to get the pH down to 6.0. Adding sulfur and lowering pH is tough in my experience!! Far easier to raise pH with lime. When a plant is not growing in its preferred pH it is stressed...cue for the spider mite. You really deserve to buy yourself a LOUPE at 10X. The microscopic world is to die for!! I found a specimen microscope up to 40X with its own light source for $14. I can't live without these guys...you have to be able to see spider mite, if not, I am wrong. But my goodness, looks like spidermite to me – stormy Jan 15 '17 at 23:11

2 Answers2

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First, I just noticed that you have 7.4 pH and that is a big no no for solanaceae. Too high for MOST plants. You need to get that plant into fresh potting soil. Normally potting soil is lower in pH. Takes a bit of time and work to lower pH UNLESS you are using potting soil. When you get fresh potting soil, test the pH with whatever you use, I use 3 different methods. 5.7 to 6.5...7.4 is very unusual. And you do have a stressed plant on a number of counts. First the spider mite which sure looks as if it is going strong. Being taken out of the garden soil and put in a pot and with the pH that high I can't comment on your fertilizer nor should you worry about fertilizer whether the chemicals are deficient or in excess. That pH has to be fixed first. Otherwise chemicals that plant needs that plant can not use until it is more acidic. That is way too high for alkaline loving plants such as lawns and marijuana!

Spider mite attack plants with much more success when a plant is stressed and weakened. And if you look closely at those leaves I'll put money down that you can see little spider mites and webbing and insect poop galore! To include white fly...I can see a bit.

stormy
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    I have pH about 7.3 (and subsoil to 7.8). Really not huge problems also for my aubergines. Maybe the vegetable garden is not so high in pH because of fertilisers (manure), but surelly not so low. I'll need to test. Only blueberries give me troubles (because of pH). – Giacomo Catenazzi Dec 28 '16 at 20:26
  • Spider mite damage doesn't start looking better for a long time...the new leaves look good, the others will not ever look healthy again. Even with high vigilance on the spider mite. The ruined leaves will fall off before they ever look healthy again. – stormy Dec 29 '16 at 21:53
  • The spider mite infestation was in July and treated at that time. These leaves are after that time. I'm wondering now if it's just aphid damage. – Graham Chiu Jan 02 '17 at 09:48
  • It is spider mite damage. Aphids aren't that big of a deal on leaves, perhaps buds, flower buds, flowers but they aren't a big deal sucking on leaves. This is spider mite damage. I've just been through hell with these things. Leaves do not recuperate. It is OK if you keep checking for live spider mite...when you get spider mite it is very apparent and there is no getting rid of it until you clean up the environment. Even then, one egg, one spider mite and the process starts again. Dunking is far superior to spraying. – stormy Jan 02 '17 at 21:18
  • I'm going to accept your answer as spraying for aphids has cleared the problem, and I can accept that there may be mites I can't see. Another pH meter says the potting mix is neutral. – Graham Chiu Jan 15 '17 at 01:20
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To me, the yellowing on older leaves looks like plain old nitrogen deficiency.

Freya
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    Welcome to SE Gardening. This answer would be improved if you explained why nitrogen deficiency would these parts of the plant (hint: are they old or new leaves primarily affected?), whether or not *Solanum melongena* is particularly prone nitrogen deficiency and whether the particular cultivation method increases the likelihood of nitrogen deficiency. – George of all trades Apr 20 '17 at 21:24