Biting gnats, borer control, planting time
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Call them buffalo gnats, black flies and other
unmentionable names, but they are back. 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 hit about 75 degrees. They will also travel up to
10 miles in search of a food source, meaning 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
Control is difficult. Sprays of malathion, permethrin or
bifenthrin will help with controlling the buffalo gnats when
outdoor activities must be held in infested areas. Dusts of
permethrin will also help with outside poultry operations.
Repellents of DEET, citronella and vanilla may also provide some
Remember, only the females bite. 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. Navy blue seems to be
their least favorite color.
Here is a listing of common borers and their control times:
ash borers, early June and early July; bronze birch borer,
mid-May and repeat two times at two-week intervals; dogwood
borer, mid-May and mid-June; flatheaded apple borer, late May
and repeat in three weeks; lilac borer, early June and early
July; locust borer, late August and mid-September; mountain ash
borer, early June and mid-July; peach tree borer, mid-June and
mid-July; viburnum borer, early June and early July; and
Zimmerman pine moth, April or August. For the emerald ash borer,
although not confirmed in our area at this time, control time in
Michigan begins in mid-May and runs through mid-July.
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The product of choice for many borers is now permethrin, since
Dursban is off the market. Imidacloprid is fairly new on the market.
One trade name is Merit, sold for homeowners as Bayer Advanced
Garden Tree and Shrub Insect Care. The use rate for this product is
an ounce per inch of circumference of the tree trunk. You then mix
it with three gallons of water and pour around the base of the tree.
It may take a few months for it to translocate though the tree. A
good time to apply it is in early spring, when the sap rises. These
treatments need to be completed by late May to have a chance of
getting the current season borers. Each treatment lasts about a
year. Fruit trees generally are treated differently, with Sevin or
just using the regular spray program, due to the possibility of
residue in fruit.
Zimmerman pine moth is also one of the borers. It generally
affects only severely weakened trees and goes just under the bark to
girdle the cambium layer. It seems like older Scotch, red and
Austrian pines are favorites when they begin to decline. Bird damage
from yellow-bellied sapsuckers on trunks and main limbs also looks
like borer damage to many. This bird damage is easily recognized by
the evenly spaced holes in a straight line.
We are approaching the planting time for warm-loving vegetables,
which is May 10 through June 1. These would include lima beans,
cucumbers, eggplant, melons, pepper plants, sweet potato slips,
pumpkins and squash. You can also put out successive plantings of
snap beans, beets, carrots and sweet corn to extend the season.
University of Illinois Extension, Logan County]