Chamaerops Humilis leaf mark cure ?

I have a couple of Mediterranean Palms which are showing black marks on the leaves. I know this is normal for the plant . Is it possible to reduce this marking ? I remove badly marked leaves and congested leaves . Is there any cure or prevention tips to reduce this marking ? Both plants are in containers.
TIA

 

Not sure Harry.
I have a fairly old Chamy that is quite big and it never has problems of this type.
I have a fairly small, although more than 10yrs old Chamy cerifera that I grew from seed, and it is getting leaf problems every year.

I can only guess this happens when they are not happy, but apart from good feeding and watering, if pot grown, I really cant think why.

When young I think they do appreciate some shade, in really hot weather.

 

A few of mine have black spots. Cut the worst ones off,fed well through summer,gave a spray of rose blackspot . Look not too bad now,still in pots that are far too small but thats life .....

 

Thanks for the answers , I'll get some rose blackspot spray today . I'll also try to improve my rather intermittent feeding regime . Would an application of palm feed every 2-3 weeks be about right ?