Q. For many years I have
grown delphiniums in my garden, but in the past eight years many of
them have been plagued with a disease that distorts their leaves and
often their blossoms. As soon as this is detected the plant is
destroyed and replaced, but soon half the replacements are also
victimized. Can this be controlled, or should I just abandon these
beauties? They are the backbone of my garden. Thank you.
A. Delphiniums are tall,
stately perennials that bloom in summer in a range of colors
including pink, blue, violet, and white. Their tall flower spikes
rise above the flower bed to provide an elegant vertical accent.
Delphiniums range in height from three feet tall to over six feet
tall. They are a short-lived perennial, but are easy to start from seed.
From your description, it sounds as if your
delphiniums may be infected with a type of virus. There are many
viruses that affect delphiniums, including aster yellows, delphinium
ring spot, mosaic, and beet curly top. The symptoms of these viruses
include stunted or distorted leaves. The foliage may also be yellowed
and have spots or streaks. Often the entire plant is stunted and has
Viruses can be spread by insects such as aphids. As
the insect feeds on the plant it spreads the disease from plant to
plant. Treat for aphids to prevent the spread of disease. One of the
easiest ways to control aphids is to spray the plants with Neem
Oil. Begin spraying early in the season as soon as the
plants begin growing in spring and spray regularly, about once a
week, throughout the season to control and prevent aphids.
Unfortunately, there is no cure for the viruses that
infect delphiniums. The best way to control them is to remove all the
affected plants and dispose of them. Do not add the diseased plants
to the compost pile. Be sure to disinfect any tools used to remove
the plants. Spray the tools with rubbing alcohol or a 25 percent
bleach and water solution. Wash your hands thoroughly before touching
any other plants.
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