I have recently purchased a desert rose. Now several of the leaves are turning brown and sometimes getting black spots. I'm not sure due to what that is. At the moment the plant receives 3 to 5 hours of full sunlight every day. Is that enough? Or could it be something fungal? I live in the tropics and it's around 90° and dry. I water once every two weeks. The soil is dry after just three days or so. The soil is around 40% organic and 60% sand.

I just had a closer look with very strong magnification and discovered a tiny red bug on several leaves. Maybe mites? I took some phone pictures through the lense. They're not clear, but I could se them move.

@rolandrumm it does look like spider mights including the bumps or holes. You can wash the leaves with mild soap.

@deepsouth do you agree it looks like spider mites?

not sure ...the first 2 pics, (of top of leaves) ....look more like physical damage ...were the plants shipped in a box ? - have they fallen over from strong winds ?

spider mites thrive in hot dry conditions ....is it hot and dry where you are ?

also , I do not see any webbing .....spider mites produce a mass of thick webbing (hard to see thru) ....like the webs of tree tent caterpillars

suggestions .... move plants where they will get more sun ...at least 6 hours worth ....water more often (leaves look droopy) ....water to saturation in several passes ...you want see water running out of pot from underneath

spray with insecticidal soap

deepsouth said: not sure ...the first 2 pics, (of top of leaves) ....look more like physical damage ...were the plants shipped in a box ? - have they fallen over from strong winds ?

spider mites thrive in hot dry conditions ....is it hot and dry where you are ?

also , I do not see any webbing .....spider mites produce a mass of thick webbing (hard to see thru) ....like the webs of tree tent caterpillars

suggestions .... move plants where they will get more sun ...at least 6 hours worth ....water more often (leaves look droopy) ....water to saturation in several passes ...you want see water running out of pot from underneath

spray with insecticidal soap

It was shipped, but that two months ago. And even new leaves turn yellow after a while. There is no thick webbing. But I saw some slight webs. I will try to take some photos. I will try to give them a sunnier spot and see how they do. It is hot, around 90° almost all year. Ow is the dry season, but air humidity is usually around 80%. I water the thoroughly every two weeks. Is that enough? I give them a good soak. Also I live on a small island and can't get any insecticidal soap or anything like it. Is there any else I can try?

Thank you so much for your help!

rolandrumm said: It was shipped, but that two months ago. And even new leaves turn yellow after a while. There is no thick webbing. But I saw some slight webs. I will try to take some photos. I will try to give them a sunnier spot and see how they do. It is hot, around 90° almost all year. Ow is the dry season, but air humidity is usually around 80%. I water the thoroughly every two weeks. Is that enough? I give them a good soak. Also I live on a small island and can't get any insecticidal soap or anything like it. Is there any else I can try?

Thank you so much for your help!

a rough watering guide based on outdoor temperature

70°f water once every 10 days -
80°f water once every 7 days -
90°f water once every 5 days -
100°f water once every 3 days -

water in several passes to ensure saturation

count any rainfall as a watering day

can you get Dr. Bronner's Pure-Castile, Liquid Soap, Baby, Unscented ??
If not ....what insecticides are available to you ??

Oh thank you so much for that watering guide. I think I had watered them too little. I was watering every two weeks at an average temperature of 86°.

I can get liquid soap and rubbing alcohol. I will try to make a mix with those and then in three weeks I can get some insecticide when I fly to the mainland. I did compare to spider mites and that is exactly what the little critters look like.

Thank you all so much!!!