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Peach
leaf curl |
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Anthracnose |
This week's highlights -- or lowlights
By John Fulton
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[May 22, 2013]
What a difference a year makes! Last
year we were warm and dry for large parts of the spring, and this
year has been cool and damp for the most part. With the type of
weather we have experienced, it should have been expected that many
different diseases would come our way this spring. Well, they are
here. Here are some shorts on the past week and some of the diseases
found without looking too hard.
Peach leaf curl is caused by a fungus on trees in the stone fruit
family. This would include mainly peaches and plums. It is rather
striking with the bright red swellings on the green leaves. This
disease can only be prevented with a dormant-time application of a
fungicide on your trees. Seeing it now means that you probably
should have sprayed before the buds began to swell (meaning before
leaves actually came out).
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Anthracnose starts as dead areas
between leaf veins or on the tips of leaves. When severe enough,
leaves will fall. Several of the infected trees have actually had
the leaves turn completely black already. On many trees, it is much
more noticeable on one side, due to air movement carrying the
disease and drying out foliage quickly. The good news is that it
rarely harms trees. If enough leaves drop, a new set comes out in
four to six weeks and we start all over. The next set of leaves may
also get the disease, but they may not. Infection can continue with
weather favorable to the disease and when nighttime temperatures
stay under 65 degrees. Treatments when you see the symptoms of this
disease are simply wasted time and money.
Apple scab, a disease similar to anthracnose, can cause premature
leaf drop in apples and crabapples. If you are on a regular spray
schedule for fruit trees, it should prevent most of the problems.
You could also spray crabapples this way, but you would have to
weigh the cost and benefit since no fruit production is involved.
As a reminder, spray programs for disease prevention in fruit
trees should be applied every 10-14 days after the bloom period is
over. It should be stressed that these are preventive programs and
not curative. These programs then continue until roughly two weeks
before the fruit is ready to harvest.
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Garden update
Just to catch up on a few things, we are now ready for the
warm-loving vegetables to be planted. This would include lima beans,
cucumbers, eggplant, melons, sweet potato slips, and summer and
winter squash. You would want to accomplish these plantings around
June 1 at the latest for summer harvests.
In another two weeks or so, we'll begin planting for fall garden
harvests already, with plants such as potatoes, summer squash and
tomatoes.
You can also do second-crop planting of sweet corn, green beans
and cucumbers. Just remember, the length of time between your first
and second plantings will not equal the time between the harvests.
Heat units and length of night affect the crops. Heat units
accumulate much faster during the summer months, and the length of
night will be equal on either side of the summer solstice.
[By
JOHN FULTON,
University of Illinois Extension]
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