Help my lemon tree is dying!

[Nyla]

I inherited a lemon tree and it is dying. It was in bad shape when I got here and I was able to nurse it back to health but over the last three months it has been dying and I have no idea what is happening to it. A kumquat tree and a little other tree in the same row are also dying. I haven't used any chemicals or pesticides, so I am really confused.

 

[alp]

Not being an expert, I've googled and found this

Citrus Black Spot. I would cut those leaves off and burn them whether it is the right diagnosis or what.

https://en.wikipedia.org/wiki/Citrus_black_spot

Have a look please. Just might be useful. Another thing is check the PH and feed the plant to make it stronger.

 

[roadrunner]

What's the condition of the soil?

How much/often do you water it?

 

[Chuck]

I inherited a lemon tree and it is dying. It was in bad shape when I got here and I was able to nurse it back to health but over the last three months it has been dying and I have no idea what is happening to it. A kumquat tree and a little other tree in the same row are also dying. I haven't used any chemicals or pesticides, so I am really confused. View attachment 31841 View attachment 31841 View attachment 31842

I think you have 2 problems. The first is the darkening of the leaf margins on a few leaves. I think this is caused by the Citrus Leaf Miner. I magnified the damaged leaves shown in the pictures and could faintly see tunnels. Don't worry about leaf miners as they cause minor damage and there isn't much you can do about them anyway. I don't think it is a fungus because the damage isn't widespread. The second and most worrisome of the trees problems is a nutrition deficiency, most notably nitrogen. Look at your pictures and you can see many many leaves which are a yellowish green. They are supposed to be the color of the darker green leaves and this yellowish color is a sign of nitrogen deficiency. If the leaves showed green veins it would be a lack of iron. Your pictures also show patches of yellowing on some of the leaves. This is probably a manganese deficiency. If it were me I would fertilize with a good organic fertilizer. I think that the nutrients have leached out of the soil over the years but good fertilization will bring back the soils health in a short period of time. And healthy soil means a healthier tree, one that fight off attacks of insects and pathogens.

 

[roadrunner]

I went back in looked at the old pictures of my Meyers Lemon tree when I was having problems with it; your tree is in so much better condition than mine was, here are some pics of what it use to look like...

My problem was that I allowed so much to grow around the tree, which sapped away much of the nutrients -- lemon trees are heavy feeders.

I cut away much of the growth (chopped and dropped), but still was not looking good, so over last winter I used fava beans as a cover crop and the following spring the tree bounced back nicely. I also had many black spots on the leaves, but after adding the nutrients to the soil it cleared that up also, because the tree's immune system was naturally strengthened -- no need for specific treatment for that fungal growth.

I have very sandy soil and don't amend with any store-bought soil/nutrients; I rely totally on building the soil, with heavy mulch, composting and cover crops.

I'm thinking your soil is more of a clay type, so I'd recommend more mulching and looking into some type of cover crop that would work in your area. Also, if you do have clay soil, the issue of watering can factor in, i.e. you may need to water less -- over-watering is a big problem with lemon trees.

Just some thoughts, until more info available, here's also a good reference: https://www.gardeningknowhow.com/edible/fruits/lemons/lemon-tree-leaves-turn-yellow.htm

 

[Nyla]

I am so grateful for your help. I've been watering twice a week, I gave it fertilizer and the soil ph is highly acidic.

 

[Chuck]

I am so grateful for your help. I've been watering twice a week, I gave it fertilizer and the soil ph is highly acidic.

You are not watering the trees correctly. Do not water by the calendar. Water when the tree needs it. A tree that size should be watered no more than twice a month at most. They should be watered heavily with a low volume hose out to the drip line of the tree and not just at the base. A soaker hose or a regular hose just barely tuned on is best. Water until the soil is SATURATED deeply and do not water again until the soil is DRY about 4 inches deep. And when you fertilize spread the fertilizer out to the drip line as well, not just around the base. You cannot over water a tree but you can and will kill a tree by watering too often.

 

[Chuck]

I am so grateful for your help. I've been watering twice a week, I gave it fertilizer and the soil ph is highly acidic.

What is the Ph?

 

[Nyla]

The ph is highly acidic, I thought we were watering too often. I've also noticed holes in the leaves that are definitely from being eaten but I've examined the leaves with a magnifying glass and I do not see where or what could be attacking my tree. Do you have any suggestions. I'm very grateful for your help.

 

[Chuck]

The ph is highly acidic, I thought we were watering too often. I've also noticed holes in the leaves that are definitely from being eaten but I've examined the leaves with a magnifying glass and I do not see where or what could be attacking my tree. Do you have any suggestions. I'm very grateful for your help.

It is probably the caterpillar of the Giant Swallowtail butterfly that is chewing on your trees. They are know as and look exactly like bird poop. I wouldn't worry about them.
Lemons like acidic soil between 5.5 and 6.5. I presume you have San Juaquin soil?

 

[alp]

Could it be fungal?

 

[Chuck]

Could it be fungal?

Possible but unlikely. Look closely at the damaged leaves and you can barely discern old physical damage. Also the damage occurs on almost all of the damaged leaves on the outer edge of the leaf.