Category Archives: Pests and Diseases

Why does my Aloe Arborescens have black leaves?

Is there a cure?

About a year ago I noticed my Aloe Arborescens were covered in dappled black marks, and after a few months the leaves turned black, shriveled and died.

 Aloe Arborescen - black marks on leaves

Aloe Arborescens – black marks on leaves

There is an old adage: Don’t put off till tomorrow what you should do today.

Unfortunately, I never acted immediately and when I did seek advice I was told it was a virus and there was basically nothing I could do to  cure it. I was then advised to remove all the affected leaves so only the new growth remained. I tried, but after spending many back-breaking hours pulling off the dead leaves I decided the plant was too far gone and we cut it back to ground level.

Apparently Aloe’s are rarely affected by pests although the root and dry rot can be a problem. I was about to give up on my mission to discover the cause of the black marks when someone suggested it could be a fungus due to humidity. Ah ha! After an extensive search of the web looking for clues I discovered:

Insects such as aphids and snout beetles sometimes attack aloes, and they occasionally fall prey to fungal diseases, such as rust, especially if they are growing close together. Spray the plants with a systemic insecticide to stop the sucking insects in their tracks.
Make sure that the poison runs into the growth points between the leaves as well. A fungicide with a copper base can help to control diseases such as rust, which are a nuisance in humid climates.

Credit: An article published on The Gardener

I am on a mission to find a fungicide with a copper base to save my one remaining Aloe Arborescen growing in another part of the garden. Can anyone recommend a product which I can buy here in Portugal or from the net?

Aloe Arborescen with black marks on leaves

Aloe Arborescen with black marks on leaves

All the plants pictured above have since been cut down to ground level in the hope they will regrow and I will get a second chance.

Fingers crossed!

Does anyone have any other suggestions or advice, please?

Other useful websites:
TipsPlants.com
PlantsAfrica.com

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