Dealing
with Rose Disease
There are three fungal
diseases roses are generally
susceptible too. When dealing with
rose diseases, the most
common of these diseases are Black spot,
Powdery and Downy Mildews, and Rose Rust. Black spot and powdery mildew
are
spread through roses by spores. These rose diseases need specific temperature,
moisture and humidity to
survive. They usually occur in early
Summer and Fall when the night temperatures are cool and moist or the
humidity is high. These diseases are fungus infections and can be
treated with fungicides.
Disease
Control and Prevention
Keeping
your roses
healthy is your first line of defense.
Healthy roses are less prone to disease. Water and adequate nutrients
through proper fertilizer and
compost will help keep your roses
healthy. When your roses are healthy, they are less likely to succumb
to disease.
Proper maintenance of
your roses will also help, remove and
dispose of any dead canes and leaves in the Spring and Fall to prevent
the spread of disease. The disease spores can live through the winter
months on old and weak leaves and reinfection can occur on any new
growth in the Spring.
You have three choices
you can do to control these diseases:
1. Do nothing or
leave your roses alone, but remember that
to much leaf loss can weaken and eventually kill your rose plant. Also
these diseases can multiply and become established through out your
rose garden site infecting your other rose plants.
2. Once disease has
infected your garden, fungicides are
an effective means of treatments
for your roses. Use chemical fungicides for roses to
establish a spraying program. Start your program in early Spring and
spray every seven to ten days. Follow the directions carefully and wear
protective eye wear and masks when spraying. For sprays to have any
effect on your diseased rose plants remember to spray every seven to
ten day during the growing season.
3. Many people do not
feel comfortable using chemical
sprays, due to hazards to humans, animals and the environment. The
other alternative is to use an organic spray which is less hazardous,
to prevent the disease from occurring. Use the same spraying schedule
you would use with chemical sprays, usually every seven to ten days.
You
may also use these sprays after you find the disease to help prevent
it's spread. Using available fungicides that contain copper, neem or
sulfur as an organic disease control can be effective against leaf spot
diseases. You can also make your own spray using this mixture: Add to
one gallon of water,
one tablespoon of baking soda and two and a half tablespoons of
Sunspray ultra fine horticultural oil, mix well. Apply this mixture to
roses in the morning and evening. Follow the recipe, higher
concentrations of both the baking soda and the oil can cause more leaf
damage. This recipe has been known to be very effective against powdery
mildews.
You can test your
recipe spray mixture on a small area of
your rose plant before completely spraying the whole plant to check for
any reactions.
Cautionary
note: Rugosa roses can have
an
allergic reaction to chemical sprays, so use caution when spraying
these roses. These sprays can cause leaves to yellow and fall off.
Rugosa roses are disease resistant and very seldom need to be sprayed,
but there are some exceptions. Some Rugosa roses maybe cross breed with
other varieties of roses that are susceptible to these diseases. It is
best to test your spray on a small area of your plant to see if it
drops leaves. If the leaves do not turn yellow and fall off, spray the
whole plant.
Learning about what
rose diseases your plants may get will
help you solve your problem. Here is a great site that gives you some
problems/symptoms of rose diseases with pictures to help you identify
what they look like, what may have caused your plants to get the
disease and what to do to solve your rose disease problem. Visit: http://www.olyrose.org/pests.htm
Content and photos
may not be copied or used without
express written permission.
Copyright 2011-2012
