This Meyers lemon has some white areas on some of the branches. I’m not able to remove or scratch it off. The tree has dropped most of its leaves in the past few months. It has many blossoms and several developing
That looks like scar tissue to me, possibly formed from some past infection. Usually it is not so white, usually such tissue is a bit yellow or brown. Not sure why it would be so white, did you use a soap or peroxide to treat something? That may be what made things so white... from the other photos my guess is the citrus needs a good dose of fertilizer and to have some of the fruit removed. When a citrus plant lacks nutrition and has fruit it will sometimes sacrifice leaves for the fruit. I would recommend removing some fruit and giving it a good dose of miracle gro or equivalent. Also, I see you are using a soilless mix. Be sure to provide calcium in some way as citrus need it and will degenerate without it. Soilless mixes have small amounts that tend to run out. Gypsum is a good source as it also has sulphur that they also need... or you could use some bone meal or a bit of lime (the mineral, not the fruit). Read the label of whatever you choose to make sure the dosage is right...
Do you know the reason behind the loss of leaves? Was it sudden or gradual? Given there are few leaves remaining on the tree I would remove all fruit and flowers. Because the few remaining leaves do not show an obvious deficiency and because the tree is under stress, I would not apply any fertilizer until it shows signs of recovery. Going forward, give it as much light as possible and water it only when the soil has dried somewhat. There'll be a much reduced need for moisture with the loss of leaves.
There was some scale on the leaves so I sprayed with safers insecticidal soap. Today I repotted the tree into a 511 mix. The soil on the bottom of the existing pot was very wet. The rootball seemed very small compared to the size of the tree. I also soaked the roots in h202 and water to kill any bacteria. I hope it recovers from whatever was ailing it.
Thank you! There was some scale so maybe that was the reason for the leaf drop. I repotted the tree today in a 511 mix. The existing soil in the bottom of the pot was very wet.
I don't think a light scale infestation would cause leaf drop. Was the tree exposed to strong sunlight during or shortly after spraying with the soap? If so, it could be the result of phytotoxicity or perhaps it was the result of root damage from an overly moist soil.
No I only sprayed when the tree was shaded. I’m now suspecting it was the overly wet soil but am still wondering what has caused the white on some of the branches. Could this be some type of bacteria perhaps?
I stand corrected. My kieffer lime also has a small section of stem with similar looking damage which I attribute to scratches on the bark. I wouldn't worry if the spots are isolated occurrences.