Thanks all for your feedback.
I had Carmonas since 15 years when I was living in Belgium, and now that I live in Dubai I bought another one. The difference is that here I keep him outdoors, because aircon kills them. I have the tree since 2 years and it is now his second "winter". Outdoor we go as low as 19 degrees C at night. So far he did not suffer from the summer heat as I water him daily and vaporise the leaves morning and evening with water. The only pest he ever suffered from was in winter last year when he was infested with cochenils but I hate treating Carmonas with chemicals, they suffer allot from treatment, so my treatment which I applied now as well is to wash the leaves and twigs softely with mild soap diluted in water and scrub gently with a tooth brush, and then spray with water from below the tree. It seems this has halted the white spots on the new leaves. I will do some sampling of the soil and check under the microscope if there are any parasites.
On the water drops side of things we have temperatures over 50 degrees C in summer peaks and I vaporise every morning and evening. I do provide shade for all my bonsais in summer.
A happy New Year to you all,
Daniel