I seem to have a periodic problem where the leaves of my D. capensis
begin to turn black from the ends inward. The problem starts with the
oldest growth and then spreads to the newer leaves and flower stalks,
eventually killing the plant. At least that's what I *think* happens.
What I've done so far is to spray the plants with "Safer" brand
fungicide (0.40% sulfur) and "Schultz-Instant" insect spray
(pyrethrins 0.02%, piperonyl butoxide, technical 0.20%, water 99.78%)
It may be my imagination, but this treatment almost seems to accelerate
the death of the plant.
Plants with no evidence of the disease/infestation seem fine, even when
treated with both compounds.
So, can either of these compounds damage a weakened plant, am I spraying
too late? I've lost three mature flowers so far and I was really looking
forward to starting a new batch from seed this year :-( I still
have a chance, but not if this stuff comes back.
Cheers,
Rick