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01-06-05
Question and Answer
Q. I have a pink lemonade
honeysuckle vine. It has bloomed all summer, but the leaves are turning
a powdery white and falling off. Is there a remedy to save my plant? --
Sylvia R. Kline, Ferdinand, Ind.
A. Powdery mildew is the name for the grayish-white
powdery coating caused by a fungus growing on plant leaves, shoots and
flowers. This disease is caused by a group of similar fungi that attacks
a wide variety of plants, including lilac, beebalm and honeysuckle.
Although plants infected with powdery mildew rarely die, the disease
can reduce the attractiveness of landscape ornamentals.
Conditions, including high humidity, overcast weather, warm days and
cool nights favor powdery mildew development. The disease is common in
crowded plantings and in areas with restricted air movement. Recommendations
to reduce infection include adequate spacing between plants and choosing
the right plant for the right location so as to make conditions less favorable
for the disease.
There is no cure for infected plants, however, preventative fungicide
sprays will help protect healthy plant tissue from infection. Products
containing active ingredients, such as chlorothalonil, triforine and sulfur,
are labeled for control of powdery mildew. Hosts and diseases listed on
specific product labels may differ between products containing the same
active ingredient, thus be sure to read the label.
At the end of the growing season, remove powdery mildew-infected leaves
from the ground to reduce carryover of the mildew fungi into the next
season.
Q. I have been fighting
sandburs in my back yard for 20 years. Someone told me to put lime on
them, but this didn't work. I have been pulling them out, but there are
too many! What can I put on them to get rid of them for good? -- Linda
Williams, Wheatfield, Ind.
A. Sandbur is a common weed
in northern Indiana on very sandy soils. Most people don't realize they
have sandbur in their lawn until they or their children step on one with
bare feet. Sandbur is an annual grassy weed that germinates in the spring,
forms the spiny burs during the summer and then dies with the frost in
fall. If you had sandbur in your lawn last year, you will probably have
it again this year. Proper mowing, fertilization and irrigation to create
a dense lawn will help to control sandbur. A number of preemergence annual
grass herbicides are labeled for control of sandbur, including DCPA (Dacthal)
and products containing pendimethalin. Preemergence herbicides applied
in spring to prevent crabgrass should also prevent sandbur. Homeowners
can also use products containing MSMA for selective control of sandbur.
If there is not enough grass on the area to justify a selective control
(a playground or sandbox for example), Roundup or Finale can be used to
nonselectively control sandbur.
Q. I have been told that
cut up leaves are good for flower beds. So this year I had the mower cut
up the leaves and had them dumped on the flower beds. When is the best
time to work them into the soil? Should I do it now or wait until spring?
Another question: I have many pots around my house and patio. What about
changing the potting soil? Is this something that should be done every
year? Every five years? I would appreciate any help you can give me. --
Sue Wessels, Lawrenceburg, Ind.
A. Work the leaves into the soil when the ground becomes
workable in the spring, taking care not to damage any existing perennials
or spring bulbs. In the future, you can do this in either fall or spring.
Chopped leaves add important nutrients and improve soil structure.
If your container plants have any diseases, the soil should be discarded
at the end of the growing season. If your plants appear healthy, the soil
can be saved and reused but realize the nutrient level is depleted with
each year of growth. A liquid or granular fertilizer program should be
followed when reusing soil. Also, the soil should be loosened before replanting
each year. Every few years, or when plants seem to grow less rapidly,
replace the soil with fresh potting mix.
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