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1. Controlling Mosquitoes
By Tom Dorn, UNL Extension Educator
Historically mosquitoes are one of the most important
insects encountered by man because they are vectors
of human diseases such as malaria (protozoa), filariasis
(nematodes), yellow fever, dengue fever, and the encephalitis
viruses, including the West Nile virus. It has been
estimated that half of all human deaths prior to 1950
(the dawn of miracle insecticides) resulted from mosquito-transmitted
diseases. Disease transmission by mosquitoes is termed
"biological transmission" because the disease
organisms multiply and complete some or all of their
life cycle within the mosquito.
For more information about mosquito species, life cycle,
and control, refer to:
NebGuide
G74-154, Mosquito Control Guide, http://ianrpubs.unl.edu/insects/graphics/g154.htm
Mosquito
Update for Nebraska, http://entomology.unl.edu/urbanent/mosquito.htm
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2. Watch For Blister Beetles In
Alfalfa
By Tom Dorn, UNL Extension Educator
Alfalfa producers should be on the alert for Blister beetles,
Epicauta spp., as they prepare for the next cutting.
An increase in blister beetles is likely because immature
blister beetles feed on grasshopper eggs, which have been
plentiful for the past couple of years. Blister beetles
feed on a plant's flowers and leaves, but usually cause
little damage. They can create a serious problem, however,
for animals that consume them in hay. Blister beetles
contain a lipid (fat) soluble blistering agent called
cantharidin, which causes blisters on skin tissue upon
contact and can severely irritate an animal's digestive
tract, especially a that of a horse.
Gray, black and three-striped
blister beetles
Image from the University of Nebraska Cooperative
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Adult blister beetles can generally be found in alfalfa
through the second and third cuttings and some years
into the fourth cutting. Horses are particularly susceptible
to blister beetle poisoning. Part or all of a horse's
digestive tract can be severely irritated, leading to
secondary infections and bleeding. Cantharidin is absorbed
and excreted through the kidneys, thus irritation of
the kidneys, ureter, urinary bladder and urethra could
be followed by secondary infections and bleeding. The
substance also lowers serum calcium levels and causes
damage to heart muscle tissue.
For more information about Blister Beetles, consult:
NebFact
NF02-551, Management of Blister Beetles in Alfalfa,
http://ianrpubs.unl.edu/insects/nf551.htm
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3. Get Ready To Plant Alfalfa
In August
By Tom Dorn, UNL Extension Educator
Alfalfa can be seeded either in spring or fall in eastern
Nebraska. Whether it is best to plant alfalfa in the
spring or fall depends on two factors- predominant weed
species and soil moisture. If the predominant weed species
are summer annuals such as foxtail and pigweed, it may
be best to plant alfalfa in the fall, provided the soil
profile has adequate moisture for growth. This allows
the alfalfa to get established with less weed competition,
and since it greens up in early spring, it will get
a head start on the annual weeds next year that must
come from seed when the soil temperature is right for
germination.
If the predominant weed species are winter annuals such
as pennycress or downy brome, spring planting may be
best. The weeds can be killed with tillage or herbicides
in early spring and then the alfalfa planted into a
clean seed bed. Pennycress, downy brome, and other winter
annual weeds are more dominant in former wheat ground
since they have the same growth habit as winter wheat.
The best time for fall seeding alfalfa in eastern Nebraska
is during the month of August, provided adequate soil
moisture is available. Farmers sometimes wait until
middle or late September to plant alfalfa. This is most
often too late because the plants do not have a chance
to become established before the first killing frost.
The latest alfalfa should be seeded in the fall is September
10. If planting cannot be completed by that time, it
is best to wait for another season.
Seed alfalfa 1/4- 1/2 inch deep in fine textured soils
and 3/4 inch deep in sandy soils for best germination.
Regardless of seeding time, it is critical that alfalfa
be planted into a firm seed bed. Alfalfa seeds must
have contact with soil particles and soil moisture to
insure rapid emergence. A firm seedbed also helps prevent
seed from being planted too deep. Leave just enough
loose soil to cover seed after planting.
Alfalfa needs to be planted into a firm seedbed, but
how do you know if the seedbed is firm enough? Dr. Bruce
Anderson, UNL Forages Specialist, says the soil should
literally be so firm you can bounce a basketball on
it or when you walk across the seed bed with hard soled
shoes, your heel should not sink in more than ½
inch. A good rain after tillage will firm the seedbed.
Harrowing with the spikes set flat or rolling with a
packer will firm seedbeds, provided there is some moisture
in the soil.
Complete tillage (disking) following row crops is okay
if the soil is firmed up by either rain, sprinkler irrigation,
or packer-seeders. If the untilled soil surface is already
smooth, no-till planters have been very successful.
In fact, no-till seeding of alfalfa following small
grain crops has become the trend among successful alfalfa
producers.
Before seeding alfalfa, whether you plant in spring
or fall, do a complete soil test. Apply and incorporate
lime and phosphorus fertilizer, if needed, and be sure
to inoculate the seed.
For more information, refer to:
NebGuide
93-652, Seeding and Renovating Alfalfa, http://www.ianr.unl.edu/pubs/Range/g652.htm
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4. White Grubs In Turf
By Don Janssen, UNL Extension Educator
White grubs are among the most destructive insect pests
of turfgrass. They feed below the soil surface on roots
and rhizomes of all commonly used turfgrass species
and cultivars, and are capable of eliminating the entire
root system of the plant. Where abundant, white grubs
are capable of destroying large areas of turf in a short
period of time.
After hatching from eggs in late July, white grubs begin
feeding on the roots and underground stems of turfgrasses.
The first evidence of injury is localized patches of pale,
discolored and dying grass displaying symptoms of moisture
stress. Damaged areas are small at first, but rapidly
enlarge and coalesce as grubs grow and expand their feeding
range. Turf in such areas will have a spongy feel under
foot and can be easily lifted from the soil surface or
rolled like a carpet, revealing the C-shaped white grubs
underneath. Damage is most apparent from mid-August through
early September when white grub feeding activity is greatest.
Inadequate irrigation and drought stress may compound
damage to turf by white grubs. Egg-laying females are
generally attracted to vigorous, well-watered turf,
and adequate moisture is essential for eggs to complete
development. Once eggs have hatched, however, white
grubs will feed on either drought stressed or well-irrigated
turf.
Several animals, especially skunks, raccoons, and moles,
are highly attracted to turf insect infestations, and
signs of their foraging in an area are strong indications
of white grub activity. Flocks of birds, particularly
starlings, feeding in the turf provide additional evidence
of a possible infestation.
For preventative control, please refer to the website
below:
NebGuide
92-1085, White Grubs In Turf, http://ianrpubs.unl.edu/insects/g1085.htm
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5. My Pond Won't Stay Full!
By Tom Dorn, UNL Extension Educator
I visited with an acreage owner last spring about
his pond and decided it would be good to share the
experience in this issue of the Acreage Insights newsletter.
The owner was wondering about sealing his pond with
bentonite clay because he thought he had excessive
seepage losses that made it impossible to keep his
pond full in summer.
After probing for more information, I learned the
surface area of the pond was about 2/3 acre. It was
situated below a very limited watershed area of perhaps
an acre. The watershed area did add runoff water to
the pond during rainfall events but did not have a
flowing spring. His main source of water for the pond
was groundwater that first circulated through the
heat exchanger in his geothermal heat pump. He could
direct the water coming from the heat pump either
to his pond or to a recharge well by switching a valve.
He was told by the installer that the pump was supplying
7.8 gallons of water per minute to the heat pump (when
the heat pump was operating).
My first thought was to calculate the water balance,
or how much water is lost to evaporation vs. how much
water is being added to the pond, before recommending
an expensive procedure like adding bentonite to seal
the pond.
Average summertime evaporation from the surface of
a pond is in the range of 1/3 of an inch per day.
An acre-inch of water, the volume of water required
to cover an acre one inch deep, is 27,154 gallons.
His pond's surface area is 2/3 or 0.67 acres. Therefore,
to raise or lower the pond's water level one inch,
it would take an addition or loss of 27,154 gallons/acre-inch
x 0.67 acre = 18,193 gallons. Since 1/3 inch of water
is evaporating each day, we can assume daily evaporation
losses of 18,193/ 3 = 6,064 gallons from this pond.
If we assume the heat pump operates 1/4 of the time
during the summer months, or 6 hours per day, how
much water is moving through the cooling system and
into the pond each day? And will that be enough to
balance the water lost to evaporation? The heat pump
is assumed to operate 6 hours or 360 minutes per day.
The water inflow to the pond is therefore 360 min/day
x 7.8 gal/min = 2,808 gallons/day.
To determine this pond's water balance, subtract the
6,064 gal/day water loss from the 2,808 gal/day water
gain. This results in a negative 3,256 gallons per
day, or an overall loss of 0.18 inches/day. (3,256
gallons /18,193 gallons/inch = 0.18 inch/day.) This
would result in a water level drop except on days
when rainwater runoff helps to fill the pond.
In conclusion, there was no need to seal the pond
because seepage was not the problem. This acreage
owner now understands that water from the heat pump
is not sufficient to maintain his pond's water level,
and that he will need to pump additional water into
the pond during periods with little rain.
Not many people use the outflow water from their heat
pump as the main water supply for a pond but many
people mistakenly believe the reason their pond doesn't
stay full is because they have excessive seepage when
in fact evaporation losses simply exceed the amount
of water coming into the pond during dry spells.
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6. Cleaning Spray Equipment
By Don Janssen, UNL Extension Educator
All spraying equipment will work better and have
a longer life if it is maintained. The most important
maintenance task you can do for your spraying devices
is to clean them. Below is a list you may want to follow:
- Check the pesticide label for any specific equipment
cleaning instructions.
- Clean spray equipment as soon as possible after
use.
- Flush the sprayer with clean water no fewer than
two times.
- Fill the sprayer to one-half capacity and add one
cup household ammonia or trisodium phosphate for each
10 gallons of water. Consult the pesticide label for
specific instructions.
- Operate the system to put the cleaning agent in
all parts of the sprayer.
- Allow the cleaning solution to remain in the system
for as long as possible.
- Pump the cleaning solution out of the system.
- Refill the sprayer twice with clean water and flush
the entire system.
- Remove nozzles and screens and clean separately.
To overwinter your equipment, drain all hoses, coat
bare metal parts with oil, store metal nozzles in oil,
and put antifreeze in the pump.
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7. When To Harvest Fruits &
Vegetables
By Don Janssen, UNL Extension Educator
Some people feel the hardest part of gardening is growing
the crop. Growing can be challenging especially on an
acreage, but harvesting the crop at it's peak quality
makes the growing more satisfying. Challenges to gardening
such as weather, insects and diseases make the journey
exciting but may reduce quality. Proper harvesting can
vanquish the enemies making the feast victorious.
Below are NebGuides designed to help you harvest your
fruits and vegetables at their proper stage of development
and help you keep the plants producing as long as possible.
Storing your produce properly will also help retain the
quality.
NebGuide
76-271, When To Harvest Fruits and Vegetables, http://ianrpubs.unl.edu/horticulture/g271.htm
NebGuide
95-1263, Storing Fresh Fruits and Vegetables, http://ianrpubs.unl.edu/horticulture/g1264.htm
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8. Care of Wild Game Meat
By Don Janssen, UNL Extension Educator
Fall will soon be here and hunting of small game and birds
will be upon us. Early season hunts may include long days
accompanied by hot weather. This combination can result
in poor quality meat or contaminated meat unfit for the
table.
Wild game provides wholesome, nourishing food, but it
should be handled and preserved carefully to retain quality.
Like domestic meat, wild meat is perishable, so care is
needed to maintain its safety.
Refer to the following factsheets for safe handling and
care of game meats.
Safe
Handling of Wild Game Birds, http://hgic.clemson.edu/factsheets/HGIC3515.htm
Safe
Handling of Wild Game Meats, http://hgic.clemson.edu/factsheets/HGIC3516.htm
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9. Watch Out For Bagworms In Your
Landscape
By Sarah Browning, UNL Extension Educator
The bagworm is an insect native to
the United States and is common in eastern Nebraska.
Bagworms feed on many species of trees and shrubs,
but are most common on evergreen trees and shrubs.
Juniper, arborvitae, pine, and spruce may be killed
if completely defoliated and less severe attacks
can slow growth. Bagworms also feed on shade, orchard,
and forest trees of nearly every kind, as well as
many ornamental shrubs and perennials, however,
severe attacks are unusual. Since deciduous plants
regrow new leaves each year, damage to them is usually
not serious. The growth of small or newly planted
trees, however, could be slowed by leaf feeding.
The adult male bagworm is a small, furry gray moth
with clear wings; the adult female does not have
wings and never leaves the bag she constructs during
feeding. The larva is a brown or tan caterpillar
with black markings. Bagworms overwinter in the
egg stage inside the female bags, which are fastened
to twigs.
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Larvae, mature bag and adult
male moth.
University of Nebraska Cooperative Extension
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The bagworm's tough, silken
bag offers protection to overwintering eggs.
Image from 'The
Bagworm In Missouri', University of Missouri-
Columbia Extension
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There may be as many as 300-1000 eggs
in a single bag. Since the female bagworm cannot
fly, local populations can build up to damaging
levels as succeeding generations of insects emerge.
Eggs hatch in late May and early June, and larvae
feed until late August or early September. There
is one generation per year.
After hatching, the larvae emerge from a hole at
the base of the mother's bag and spin down a strand
of silk. The tiny insect is often ballooned by the
wind to nearby branches or plants. Once a suitable
host is found the new insect immediately begins
to form a new bag over its body. Initially the young
insect's bag is about 1/8 inch long, but at maturity
will grow up to 2 inches long. By mid-August the
mature larvae attach their bag to a branch with
a strong band of silk and begin to pupate. Adult
males emerge in September. |
Larvae damage host plants by feeding
on the leaves and causing defoliation. Bagworms
can be controlled on small plants by handpicking
during the winter and spring before the eggs begin
to hatch in late May. Destroy bags by burning, immersing
in kerosene or by crushing. If bags containing larvae
are discarded on the ground, the larvae can return
to host plants.
Bacillus thuringiensis, BT, is an insecticide
that is effective against the young caterpillars
after they hatch in late June. BT is available at
nurseries and garden centers as Dipel or Thuricide.
Chemical control of bagworms can also be achieved
with Sevin (carbaryl), Eight (permethrin) or several
other chemicals. Affected plants must be thoroughly
covered with the insecticide so that it is ingested
by the insects as they feed. Chemical control is
most effective against small larvae, rather than
older, mature larvae.
For more information on controlling bagworms, refer
to:
NebGuide
673-4, Bagworms, http://ianrpubs.unl.edu/Insects/g4.htm
HGY2149-90,
Bagworm And Its Control, http://ohioline.osu.edu/hyg-fact/2000/2149.html
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