Re: CULT: Blyth irises
Marylou G. Gibson wrote:
> >I have never had any type of rot during our winters, but I spray twice a
> >month for leaf spot, which likes our cool and wet winters.
> >Rick Tasco
> >Superstition Iris Gardens
> >Central California
> >Zone 8
> Dear Rick,
> What is leaf spot and what do you spray for it?
> Marylou Gibson
> Carlsbad, CA Zone 10
Leaf Spot is a fungal disease of mainly bearded iris, although I have
seen it to a lesser degree on Louisiana's and Spurias. Small circular
to oval spots looking watery or greasy appear on the leaves. After a
day or two these enlarge and turn yellowish to brown and often develop a
distinct red-brown border. If plants are severely infected, leaves may
die back from the tip and the lack of green foilage may affect flower
stalk size, bloom size and general vigor of the plant. However, the
disease is not lethal. The fungus becomes a problem during wet seasons
of the year when temperatures are above freezing.
I spray my iris during the winter which is our rainy season. Usually
our winters are mild enough to promote this disease. During some colder
spells I have noticed that the Leaf Spot will be arrested. However I do
spray every 10 to 14 days usually from late October through March. I
rotate about 3 fungicides which are listed for leaf spot. Daconil, Fore
and Bayleton. I once used Benlate, which was very good, but iris was
removed from the label.
Superstition Iris Gardens