oliver75 - I don't have any answer for you, as I, too, am a complete novice with dahlias. But I have some brown on a bud now and then, as well as some leaves getting brown (quite a bit). I'm replying to your post because I can see that nobody has come forth with any help for you. I thought I'd mention the forum called "Pests and Diseases" on the general list of the garden forums. I posted a question there and got a couple of good answers, so you might give that a try.