On Thu, 26 Jun 2003 12:18:53 -0700, Cass
wrote:

In article m, Shiva
wrote:



It goes through bloom-start new growth-blackspot old foliage and drop
it-grow more-bloom-start new growth cycles. I've never seen blackspot
bad enough that all the leaves drop. Just doesn't happen here. Maybe I
don't have enough blackspot-prone roses to completely defoliate.

Or, you just don't live in as moldy a place as I do, or more likely, a
combination of both. Hybrid teas defoliate entirely here after four
weeks without fungicide. And it does weaken them, though I am very
good about lots of good feeding and lots of water to the root systems.




Babies get the most spot here too. It's got to be the containers
harboring fungi.


I meant mine in the ground, but I can see that.





It's not mysterious. It's a hormonal thing. The plant directs the
auxins to the new growth tips, in effect starving some older growth.

Ahhh, I see now!


Take a look at every new stem that grows out of a basal on Granada.
You'll see it. The bottom leaflet is fine until after bloom. Then a new
growth bud somewhere will break and you'll probably see two leaflets
suddenly age and die. The two leaflets that will die are (1) the one
just below the new bud growth and (2) the one where the stem first
broke out of the basal. During that dying process they often show
blackspot or other fungal disease (tho the good ones just yellow), just
like healthy leaflets you cut off and drop on the ground.


I certainly have seen this but never thought if the black spot being a
function of new leaf development. I believe that is how you put it.
Sounded like as long as Mutabilis is making new leaves you will have
spot.