Powdery mildew on zinnias?

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Powdery mildew on zinnias?

Post by Bulldo » Wed, 14 Oct 1998 04:00:00



I believe my zinnias may afflicted with powdery mildew.  The flowers are
fine, however the leaves look horrible.  They have many white powdery spots
and turn black/brown very quickly.  I ended up ripping both my zinnia bushes
out because they looked so sad after I picked the dead leaves off that I
couldn't stand to look at them every day.  Does this sound like powdery
mildew?  If so, are the seeds also affected?  I have been saving the seeds
from these plants, but if they are infected then I will throw them out.  Any
info you could give me would be greatly appreciated.

Thank You,
Bulldog

 
 
 

Powdery mildew on zinnias?

Post by John Ladas » Wed, 14 Oct 1998 04:00:00


Quote:

>I believe my zinnias may afflicted with powdery mildew.  The flowers are
>fine, however the leaves look horrible.  They have many white powdery spots
>and turn black/brown very quickly.  I ended up ripping both my zinnia bushes
>out because they looked so sad after I picked the dead leaves off that I
>couldn't stand to look at them every day.  Does this sound like powdery
>mildew?  If so, are the seeds also affected?  I have been saving the seeds
>from these plants, but if they are infected then I will throw them out.  Any
>info you could give me would be greatly appreciated.

        This will tend to happen to zinnias in the fall if a) they received
overhead water and b) they're in a spot that gets less than full sun.  The
Sunset Western Garden Book strongly recommends ground water only for zinnias.
I didn't quite get the drip system installed before my wife planted the
flowers this year (the main pipes and risers are in the ground).  I am care-
ful to water on the ground only, but my wife is sometimes in a hurry and
will drench the plants with an overhead spray.  The zinnias that are closer
to the trees, the ones that get more shade, are starting to get white spots
just like you have seen. The ones in full sun are O.K., but this may vary
depending on your local humidity and rain conditions.  Western California
is still reliably dry.

        Don't know about the seeds, but like you, I have noticed that the
flowers seem to be unaffected by the fungus.

--
Rainforest laid low.
"Wake up and smell the ozone,"
Says man with chainsaw.                                 - John Ladasky

 
 
 

Powdery mildew on zinnias?

Post by B & » Wed, 14 Oct 1998 04:00:00


Base watering is always a good idea with most plants that are easily infected
with powdery mildew, and zinnias are such a plant. It helps to plant them far
enough apart and in an open location so that the leaves dry easily.

Lilacs are a common source of infestation. When I got rid of my lilacs, powdery
mildew decreased markedly. There are years when humidity and rainfall combine
to infect any susceptible plant with this disfiguring disease. In such years, a
weekly spraying with the fungicide Daconil keeps it at bay.

John

Quote:

> I believe my zinnias may afflicted with powdery mildew.  The flowers are
> fine, however the leaves look horrible.  They have many white powdery spots
> and turn black/brown very quickly.  I ended up ripping both my zinnia bushes
> out because they looked so sad after I picked the dead leaves off that I
> couldn't stand to look at them every day.  Does this sound like powdery
> mildew?  If so, are the seeds also affected?  I have been saving the seeds
> from these plants, but if they are infected then I will throw them out.  Any
> info you could give me would be greatly appreciated.

> Thank You,
> Bulldog

 
 
 

Powdery mildew on zinnias?

Post by IrisCoh » Sat, 17 Oct 1998 04:00:00


Quote:
>I believe my zinnias may afflicted with powdery mildew.

Yes, some zinnias get powdery mildew. Grow something else.
Iris, Zone 5a, Sunset Zone 40
"The trouble with people is not that they don't know but that they know so much
that ain't so."
 Josh Billings, 1818-1885.
 
 
 

Powdery mildew on zinnias?

Post by JFR » Mon, 19 Oct 1998 04:00:00


Quote:

> >I believe my zinnias may afflicted with powdery mildew.

> Yes, some zinnias get powdery mildew. Grow something else.
> Iris, Zone 5a, Sunset Zone 40
> "The trouble with people is not that they don't know but that they know so much
> that ain't so."
>  Josh Billings, 1818-1885.

Towards the end of season, when the sunlight is low and the humidity and
moisture up and temps are cooling off;  it is almost unavoidable with
typical zinnias.  There are more mildew resistant ones available now.
The small linearius and the mexican golds (haagens?) are good choices
that are not affected at all.  Both are smaller plants though than the
big boys....

John R> z8b, Austin