The leaves of the my Aloysia plant developed brown spots. Initially I thought they were tiny insects, so I washed the leaves and indeed some of the spots were removed, but other spots could not be removed. The brown spots look and feel like dry leaves in the autumn.

I cut all the branches with the leaves with brown spots, and a day or two later, I noticed tiny sprouts of fresh clean leaves starting to grow. Now my questions are:

  1. Are these brown spots only a sign of old age, so that the new leaves will be OK? Or, are they a sign of some illness that might infect the new leaves?
  2. What can I do with all the branches that I cut, with the brown-spotted leaves? After washing them well, can I use them for tea?
  • 1
    Do you have some pictures for us to look over? It would help with identifying the problem.
    – TeresaMcgH
    Commented Mar 19, 2014 at 22:50
  • Unfortunately my camera is not working. It looks quite similar to this one: gardening.stackexchange.com/questions/5638/… However, in contrast to that question, it does not drop off when the plant is touched or shaken. Commented Mar 20, 2014 at 15:12

2 Answers 2


If the brown spots cannot be removed, then they are in the tissue of the leaf. The cause is hard to determine without pictures - leaf spot (either bacterial or fungal) can cause this type of damage, or insects grazing on the leaf surface can produce dry, brown areas. As far as I've been able to establish (information I found was for Aloysia citrodora, I don't know which variety you're growing), if you cut out the brown areas, you can use the remainder of the leaves for infusion purposes, provided the rest of the leaf area is healthy.


The plant in the picture you linked to looks to be suffering from a combination infestation of both aphids and whitefly. If yours looks just like this, then I'd treat it with a lukewarm water spray wash and some insecticidal soap. Treat it several times, a few days apart, ending with a good spray wash to remove any sticky aphid residue and any insecticidal soap remaining. You might also try some whitefly traps nearby to catch them before they spread. Lastly, try to keep the plant in its happy place as far as temperature and moisture goes, because stressed plants tend to attract more pests.

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