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by Rett Davis | |
Gardening Q&A by Rett Davis appears in
Alamance County's daily newspaper, The Times-News,
every Sunday in the Accent section. Each week's installment is
posted to this
website, beginning with January of this year. Scroll to the bottom of
this page to navigate to other Gardening Q&As. Please contact
Rett via e-mail with questions
or
comments in regard to this column.
Question:
Just as I was about to pick the best plum crop I have ever
had, the fruit is falling off and rotting. What is happening?
Answer:
This is the number one disease problem on peaches and plums.
Brown rot is a very destructive disease especially during wet periods.
The initial infection from this fungus begins during the blooming
period. The most destructive phase is on the fruit. As the fruit
matures the disease gets more destructive. Infected blossoms, twigs,
and fruits soon become covered with gray-brown tufts of spores. The
brown rot fungus will overwinter on mummified fruit on the ground or
tree. It is obviously a lost cause for this year. But for next year,
be prepared to spray a fungicide. Spray the entire tree, fruit, twigs,
leaves and all. I would recommend using a product containing
myclobutanil (Immunox). Spray according to label recommendations.
Begin spraying during blooming and continue every 10-14 days until
harvest. The waiting period between spraying and harvest is on the
label. In the meantime rake up all fallen fruit and remove all unwanted
fruit from the tree.
Question:
We had an entire new landscape installed two weeks ago. Now
we have crabgrass coming up through the pine needle mulch. If something
is not done now, it will be all grass in a matter of weeks. It is very
difficult to hand weed it all because of the mulch. What can we do?
Answer:
I would use a grass herbicide such as Vantage, Ornamec, or
Poast. These products do a great job on grasses. They will not harm
your new shrubs or flowers even if you accidentally spray them. Some of
the grasses such as bermuda or wiregrass will actually grow into the
shrubs making it hard to hand remove. However, the grass herbicides
will not harm broadleaf plants. Unfortunately broadleaf weeds will not
be harmed either. Just grass is susceptible to these herbicides. One
word of caution, when temperatures are above 85 degrees and the humidity
is that high too, these chemicals will cause some burning to broadleaf
leaves. Therefore, spray these chemicals on predicted cooler days and
in the late evening if your spray will come in contact with the foliage
of desirable plants.
Question:
The bottom leaves of my tomato plants are yellowing. I
switched to newer varieties this year hoping to avoid all these tomato
disease. Why is it not working?
Answer:
Because there are no varieties resistant to all the tomato
diseases. A quick check in my 'Tomato Disease' manual lists 55 diseases
and disorders of tomatoes. A majority can be found in Alamance County
during each growing season. I doubt you will ever see a tomato variety
with all that resistance. There are many diseases that cause yellowing
of tomato leaves. The most common is one called 'early blight'. There
are no varieties immune to this disease. Some will vary in their
resistance. Our most popular variety, German Johnson, catches every
disease that floats by. But we still plant them because they taste so
good. It is a sacrifice most are willing to make. If you want to
follow a schedule of spraying various fungicides religiously you can
protect your plants from many of the tomato diseases. But few
homeowners have the time to commit to this practice. Spraying should
start the day the plants are planted and continue all the way through
harvest. Homeowners also have a general fear of pesticides. Organic
growers will use copper sprays, mulched plants, and drip irrigation. It
helps, but the disease still will appear. If you wish you can pinch off
the most infected leaves. Lastly, don't plant all your tomatoes at the
same time. Stagger your plantings every 3 weeks so you will have
tomatoes up to frost.
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If you have any horticultural questions, please direct them to Rett Davis