Black Tip on Leafs..

[murihikukid]

Hi..Would anybody be able to tell me what this is....I had it in my Greenhouse plants...then I got some cuttings from a gardening centre and prepared them inside specificly to keep everything away from the greenhouse environment and now even some of my small cuttings now have it.....
on the bottom branch the tip of the end leaf will turn black like the tip of an arrow...It will then work its way round the outer edge while other leaves start showing the same ....over time the leaves will gradually curl up ..and finally the branch just drops of....My photos show it in the early stages and I do not know if it can be got rid of unless the branch is cut off and even then is the cutting effected elsewhere....Thankyou for any help..Regards Ron