Swarming and Biting Gnats, Tree Leaf
Diseases, Master Gardener Plant Sale
By John Fulton
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[April 28, 2016]
Swarming and Biting Gnats Have
Returned - Spending some time outside over the weekend and early
in the week, it seems the dreaded gnats have returned, and at least
some of these are the early buffalo gnat populations. The small
flies, or gnats, are hatched in clean, running water. This is one
indicator our water protection plans are succeeding. They will
continue to hatch until water temperatures hits about 75 degrees.
They will also travel up to 10 miles in search of a food source,
Male buffalo gnats feed on nectar while the females feed on
nectar and blood. These insects can produce serious welts when
they decide to bite. They tend to be worse during the day, and
are seldom a problem inside buildings. In addition to people,
they tend to attack birds. Young poultry and wild birds are
especially vulnerable. Some poultry insecticide treatments, such
as insecticide dusting, will help control the gnat populations.
Control is difficult. Sprays of malathion, permethrin, or
bifenthrin (or area fogging) will help with controlling the
buffalo gnats when outdoor activities must be held in infested
areas. Of course, their robust travel habits mean area
treatments will be short-lived. Dusts of permethrin will also
help with outside poultry operations. Repellents of DEET,
citronella, vanilla, and some of the other plant based
repellents may also provide some relief. It seems like the
vanilla, or a commercial product such as Buggins or black fly
ointment, are much more effective than the DEET. Remember, only
the females bite and the males swarm your face. When the bite
occurs, a chemical is injected to help with blood flow. This is
often the reason for the painful welts, usually on the face.
Children also seem to be bitten, and affected, more than adults.
The gnats seem to be attracted to white clothing, while Navy
blue seems to be the least favorite color of the buffalo gnat.
Tree Leaf Diseases
One of the normal scourges of spring has hit us again. This is
the group of fungi collectively known as leaf spot fungi. Common
ones include anthracnose and apple scab. Anthracnose starts as
dead leaf 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. It is much more noticeable on one side of many trees as
well, 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 4-6 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.
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Apple scab is a disease similar to anthracnose, and 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 preventative
programs, and not curative. These programs then continue until
roughly two weeks before the fruit is ready to harvest.
Master Gardener Plant Sale
The 15th annual plant sale by the Logan County Master Gardeners
is scheduled for Saturday, May 14. It will be from 9:00 a.m.
until 11:00 a.m. in the Logan County Special Event Building
(located across from the Fair Secretary’s Office on the South
end of the fairgrounds). Types of plants for sale include
perennials, annuals, heirloom tomatoes, peppers, ornamental
grasses, houseplants, and a limited number of shrubs. There are
no early sales available.
[By JOHN FULTON, COUNTY EXTENSION
DIRECTOR SERVING LOGAN, MENARD, AND SANGAMON COUNTIES]