Rose Pests and Diseases
Take a leisurely walk through the garden every few days and enjoy the
rewards of your labor. At the same time keep your eyes open for early
signs of trouble, such as wilted foliage, deformed flower buds, or spots
on leaves.
If you discover such warnings, don't jump to the conclusion that your
garden is disease-or pest-ridden. Take time to diagnose the problem. If
you find insects on the plants, for example, be sure they're not
beneficial insects that prey on damaging insects. Remember, too, that
many plant problems can be caused by a gardener's oversight or neglect.
Not enough water causes wilt; too much water can cause rot; alkaline
soil can cause yellow leaves. Before spraying, make sure the problem is
not a cultural one.
Prevention Is the Key
A healthy and vigorous rose can withstand more injury than a rose that
is under stress from lack of water or nutrients.
Buy high-quality plants that show no abnormal swellings on the roots or
crown (where the stem and the roots meet, just below the bud union) and
no discolored areas on the canes. The bud union should be free of
cracks. Buy from reliable sources that guarantee their products to be
disease-free. To further reduce the chance of disease, choose one of the
many cultivars that have proved particularly resistant to common rose
diseases.
Some diseases can be prevented by watering correctly. If you are
watering overhead, water only in the morning so the foliage has a chance
to dry out before nightfall. If you are irrigating by hand, use a water
bubbler on the end of the hose to prevent soil or mulch from splattering
on the leaves. This technique slows the spread of certain diseases, such
as blackspot.
Perform maintenance pruning throughout the growing season. Remove all
canes showing cankers, or discolored sunken spots, as soon as you detect
them, and destroy the prunings. Remove and destroy individual leaves
bearing black spots as soon as you notice them.
Don't forget a winter cleanup. There will be fewer insects and disease
organisms when theA healthy and vigorous rose can withstand more injury
than a rose that is under stress from lack of water or nutrients.
Buy high-quality plants that show no abnormal swellings on the roots or
crown (where the stem and the roots meet, just below the bud union) and
no discolored areas on the canes. The bud union should be free of
cracks. Buy from reliable sources that guarantee their products to be
disease-free. To further reduce the chance of disease, choose one of the
many cultivars that have proved particularly resistant to common rose
diseases.
Establish a regular spray schedule for pest and disease control during
the growing season. You may never see any evidence of pests or disease
if you regularly take the time every two weeks or so to spray or dust
the plants with a multipurpose pesticide. This program shouldn't take
more than about an hour every two weeks for most rose plantings.
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