Black leaves on lemon tree
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Shallot Man
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Hi . Have black leaves on the memsahibs Lemon Tree. Have had conflicting advice, from copper spray, and a fungicide to washing with a spray oil, what ever that is.
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Motherwoman
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Is the lemon tree outside? If so it will have got the frost. If it's black mould that rubs off it will have got scale insect.
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FelixLeiter
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You might need to be a bit more specific when you say that the lemon tree has "black leaves".
If the leaves have turned uniformly black, then they may have been frosted. In which case they will falloff, and new ones may appear in the spring. It's not unusual for a lemon to completely defoliate over winter, even when kept frost-free.. Prune it hard in late winter when new growth starts to show.
If, on the other hand, the leaves are in reasonable shape but appear pied with soot smuts, then it's sooty mould. This is a fungus which grows on any sweet residues on the leaves and stems. It is not in itself harmful (although it does block out some light) — it is a symptom, rather than a cause. It is a consequence of an infestation from insect pests — scale, mealy bug, aphids etc., or combinations thereof. It is, however, ugly. It is easy to wash off with lukewarm (not hot!) soapy water and a cloth. Fungicides will kill sooty mould, of course, but you're still left with dead sooty mould. It does work to prevent it, though.
If the leaves have turned uniformly black, then they may have been frosted. In which case they will falloff, and new ones may appear in the spring. It's not unusual for a lemon to completely defoliate over winter, even when kept frost-free.. Prune it hard in late winter when new growth starts to show.
If, on the other hand, the leaves are in reasonable shape but appear pied with soot smuts, then it's sooty mould. This is a fungus which grows on any sweet residues on the leaves and stems. It is not in itself harmful (although it does block out some light) — it is a symptom, rather than a cause. It is a consequence of an infestation from insect pests — scale, mealy bug, aphids etc., or combinations thereof. It is, however, ugly. It is easy to wash off with lukewarm (not hot!) soapy water and a cloth. Fungicides will kill sooty mould, of course, but you're still left with dead sooty mould. It does work to prevent it, though.
Allotment, but little achieved.
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Shallot Man
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Thank you both for your prompt reply's. The tree is only kept outside in the summer. Then brought into the greenhouse. Have removed a leaf and as FelixLeiter has said, can be washed off with warm soapy water. this is now top of the list of the many jobs the Memsahib wants done. Will seriously mull it over in my mind today at the Rugby Club bar. Wishing you all a Merry Xmas and a good growing year in 2015. 