Path to perfect health of Lime and Lemon trees


Hi all,

New to the forums, seems like a great, wise group! I recently moved into a house from an apartment, which has the benefit of outdoor space to do some crafting. House came with a lime and what I believe to be a lemon tree. :yum: I am not sure of the varieties and the lemon hasn’t yet produced a ripe fruit though they look to be large (5"+) and yellow… Pictures are below, they seem to be fairly healthy, the lime specifically blossoming and bearing like crazy, but have some problems. I also am reading to learn about the best way to prune the smaller lime tree as it’s kind of all over at this point.

I had a fair amount of white flies on the lemon tree when I moved in but have been spraying with water periodically and top dressed with worm castings, which I had been told/read works once a certain compound from it is taken in by the tree. This combo has seemed to work as I notice much fewer flies now.

Starting with the lemon (larger tree):

  • I notice black bugs on some of the new growth and the growth looks more stunted and curly vs other new growth (picture of reddish growth with black bugs in the linke below)
  • Really only the southwest “branch” (lefthand side on the overall picture) bears fruit, the other main branches do not

Lime (smaller tree/bush in the picture) has 3 things I notice:

  • Leaf curl
  • Leaf yellowing
  • Little tips at end of some tiny fruit turn black and brittle and generally the fruit also then turns black and falls off

Photos of these are here (can’t post more than 1 pic because I am new!): Google Photos

Thanks for any and all help you can provide!! Really enjoying taking care of these so far and will be adding a couple new fruits this winter.



Welcome, please give us your location so we can offer better advice. :slight_smile:


Sorry, I’m in the San Francisco Peninsula, the city of Burlingame. I believe I am USA zone 10a, Sunset zone 16, it gets a fairly good wind in the afternoon here but in backyard where these are there’s a few gates and buildings providing a wind block and it heats up quite a bit in the afternoon as a result (up against a south-facing wall).

Even more info… I’m in Zone B (confirmed Sunset 16) based on this UC Davis publication:


I know you’re location well. It’s ok for lemons and limes.

If you are convinced that is possible to raise healthy Citrus in your area by “natural” means alone then you’re sadly mistaken and I cannot help you. Your challenges are as follows:

Citrus Leaf miner. Regular application of Spinosad can control it, alternating with Cyfluthrin and/or Imidachloprid works better. Expect a minimum of 10% leaf curl on your trees.

Mildew, including black sooty mold. Rinse off the tree completely with water, then a day later treat with copper. Twice a year (winter and summer) is sufficient in many locations. An excellent consumer-grade product available here in California is Monterey Gardens brand “Liqui-Cop”.

Aphids and scale. If you are treating regularly for Citrus Leaf Miner these should not be a problem.

Snails and slugs. Use “Sluggo”. It’s healthy for plants and most animals but bad news for terrestrial mollusks. It is bait – so put it around the perimeter of your plants, not the base.

Overwatering. If the leaves are yellowing from the center outwards then the roots are too wet too often. When the opposite occurs it is underwatering.

Feeding. Citrus are heavy feeders. Feed them 2-3 times a year with a Citrus Food which has the first and last numbers equal and the middle lower; for example 8-4-8.


Thanks Richard, I was rather whimsical with the use of “perfect”, but the advice is helpful.

I don’t see the same type of damage on my trees that is shown in internet pictures of CLM with the trails on leaves… so I assume I don’t yet have that problem. Given your response, I take the black bugs in the picture are aphids, at this point I’ll try controlling with some natural predators to the aphids or neem oil until I see the situation get worse.

I also haven’t seen any evidence of snails or slugs anywhere in the yard but I may not know what to look for other than the bugs themselves or their tracks…

I believe the yellowing is occurring from center out so will lengthen time between waterings.


When you see the damage it is too late to treat.


Oh no! I’ve searched leaf miners because my citrus has them. I started spraying neem oil as soon as I saw them, but they haven’t budged. I guess I started too late. Does this mean doom for the tree then?


Neem oil will not control leaf miners.


Dormant oil will cure most citrus ills except leaf miner. It is non toxic. Spinosad will get the leaf miners and it is used by “organic” farmers.


Thank you, I wonder why so many people recommend it. But I’m not sure if I should try the Spinosad since there’s already damage. Also, what’s really the difference between organic or not in home gardening? I know I don’t want to use Roundup, but honestly I read the bottle of an organic pesticide and it was 99% “other ingredients” and it kills bees, so I didn’t see why it was considered better. I am no expert, of course


Neem oil and dormant oils won’t help with ACP, citrus gall mite, citrus thrips, or black sooty mold either.


Thanks! I’m going to get some Spinosad and keep my fingers crossed


I spray my citrus trees with a Solo 451 and use dormant oil, spinosad, surfactant, and Scott’s STEM. Kills them all and greens them up. Also soil drench with imidicloprid once a year. I thought sooty mold was from white flies.


Black sooty mold is ubiquitous in western California.