Freeze damage, fairy rings and millipedes
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[April 24, 2014]
Freeze damage: I
mentioned freeze damage in the column last week. Now that some time
has passed, it is somewhat easier to assess damage — and take
corrective action. Damage may still appear worse than it is today,
but it won't improve any. The reason I say it may get worse is the
simple fact that brown leaves on broadleaf evergreens are still
attached to stems that have some life in them. If damage was severe
enough, the stems will also continue to die back a little further.
Broadleaf evergreens — including boxwood, azalea, rhododendron,
holly and yew — probably took the last cold snap the worst. The
statement of fact is simple: Leaves that have turned brown will not
turn back green. There may be live buds yet on some of those stems
with some life in them, where the layer under the outside is still
green and pliable. In some cases there isn't any hope for some of
the branch tips, or even for some of the branches.
If there is still green under the dead area, you could always
prune or shear just under the dead area. This would get rid of the
dead material for the sake of appearance and also help spur new
growth. An added benefit would be thickening the remaining shrub or
tree. Entirely dead branches should be removed. After removing
these, and giving the haircut, you can assess what is left. Then you
can determine if you want to keep that — or start over. Pruning this
early in the season may lead to some "rank" growth. This could be
pruned again at the proper time in late June.
Dark green grass in rings that look like a target pattern is a
symptom of fairy rings. Fairy rings are visible now. Fairy rings are
caused by a fungus that is in the soil. Actually there are about 50
fungi that can cause fairy rings. These fungi feed on decaying
organic matter such as large roots from trees that were in the area
or from buried lumber. The dark green circle part of the equation
comes from extra nitrogen that becomes available as the organic
matter is broken down by the fungus.
Some prevention will help keep the problem from occurring. Simply
removing stumps and large roots and not burying lumber will help
prevent this type of problem.
As for a cure, fungicide drenches have been successful on a very
limited basis. One option is to mask the symptoms of the dark rings
by fertilizing the surrounding grass with a high-nitrogen fertilizer
to make that grass green also.
What are millipedes? They belong to the arthropod class Diplododa,
which means double-footed. The reason is simple: They have two legs
per body segment. There are many different types of millipedes —
over 1,000 actually. They prefer to live in moist places, such as
under mulch, in flower beds, in good-quality lawns and under wood.
They feed on decaying organic matter and occasionally on tender
leaves or roots.
[to top of second column]
Unlike centipedes, millipedes don't bite or sting. They do
give off a bad odor when disturbed or smashed. Be careful
crushing them on carpeting, as they can cause a stain.
If you're not sure whether you have millipedes or centipedes,
here are some differences: Centipedes have one leg per body segment,
while millipedes have two; centipedes normally have much longer legs
than millipedes; and centipedes move rapidly, while millipedes move
Nonchemical controls aim at removing the moist resting places.
Dethatch your lawn to reduce that damp thatch layer just above the
soil surface; closely mow and edge the lawn to allow it to dry
quickly; remove debris that provides hiding places; pull mulch away
from the house; water grass in the early morning; and keep leaves
from piling up along the foundation.
If millipedes get inside the house, the vacuum cleaner is
probably the best control. It is nonchemical and prevents stains
from smashed millipedes. Other controls in the home include sticky
boards such as are used for mouse control, aerosol sprays that are
used for flying insects, and baseboard sprays used for ants.
Outside the house, start with a foundation spray such as propoxur,
permethrin or Sevin. Spray the foundation and the adjacent foot or
so of soil and plants or lawn. Make sure you treat doorways and
other openings as well. Since millipedes aren't insects to begin
with, don't expect complete control with a chemical spray program.
University of Illinois
Extension director for Logan, Menard and Sangamon counties]