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Outdoor Insects
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Fall Armyworm Moths
-by Dennis M. Ferraro Extension Educator Douglas/Sarpy Extension
Unit
The tan, fuzzy egg masses appear on home siding or lawn furniture,
and hatch.
In turfgrass, especially fescue, be alert to areas of the lawn that
appear "frosted" or brown, where young fall armyworms etch away
green tissue, creating "window-pane" damage. Later, entire blades
are devoured.
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Green Cloverworm Moths
-by Dennis Ferraro Extension Educator Douglas/Sarpy Extension Unit
When at rest, the moths are triangular (deltoid) in form. They have
a long snout.
Host plants for larvae include soybean, alfalfa and clover, but
significant infestations in the future are not likely.
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Sod Webworm Moths
-by Dennis M. Ferraro Extension Educator Douglas/Sarpy Extension
Unit
Due to low moist levels and a colder than normal spring this year
these insects are low in numbers. Over the past several weeks, very
few instances of sod webworm moths have been observed. Usually, the
larvae begin to emerge in May and eat very little grass because it
turns into a moth soon after emerging. This spring, the insect may
be in lawns longer than usual because of cooler conditions.
The larvae hide in soil or thatch during the day and feed at night
on grass blades near the soil surface. Due to this habit, early
spring cold night may kill many of the pests.
The sod webworm larvae is a worm about 1/2 to 3/4 inch long,
grayish-brown in color with a brown head and dark spots on the body.
To determine infestation, apply a mixture of 1/4 cup household
detergent and a gallon of water over a square yard of lawn. This
irritates the webworms, causing them to squirm to the surface in
five to 10 minutes. If 15 or more larvae are found in a square yard,
controls may be justified.
Water and mow lawns before applying insecticides. Insecticidal
controls include Dipel, Diazinon, Sevin and several other products.
For best results, apply liquid insecticides in late afternoon or
early evening to coincide with pest activity. Don't remove lawn
clippings for a week or two after application, so that the
insecticide remains on the lawn.
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White Grubs
-by Dennis M. Ferraro Extension Educator Douglas/Sarpy Extension
Unit
This lawn pest can be effectively controlled chemically only when an
insecticide reaches the grub where and when it is feeding. That
makes timing important.
Monitoring of the masked chafer, the beetle responsible for 90
percent of the white grub problems in this area indicates that any
chemical controls should be applied Aug. 1 through Aug. 20. If you
use a control agent that has a short effective period, apply it
after Aug. 8. )Calculated monitoring done by Cooperative Extension)
A lawn that is in good condition can tolerate moderate grub
infestation. Some root damage may occur, but recovery can be aided
by adequate watering, fertilization in early September and late
October, and reseeding thinned areas with improved disease-resistant
cultivars of Kentucky bluegrass, tall fescue or perennial ryegrass.
White grubs live through the winter about six to 12 inches below the
soil surface of the lawn. They move closer to the surface as the
soil warms in early spring, and a small amount of non-destructive
feeding takes place then. The grub is a curled white worm about an
inch long and 3/8 inch in diameter, with a caramel-colored head. If
a lawn was checked at that time of year and more than five to eight
grubs found per square foot, chemical control to prevent damage is
warranted. An insecticide is probably also needed if the lawn or
neighboring lawns had white grub problems last year.
Adult beetles which develop from those grubs deposit eggs below the
soil surface in mid-July. Upon hatching, these young grubs
immediately begin devouring turfgrass roots. The damage occurs when
the grubs are half grown and feeding voraciously.
Insecticides are effective against grubs only during the active
feeding stage. The chemical must get into the soil below the thatch,
where the young grubs are feeding.
If the lawn was not aerated in the spring and there is more than
one-half inch of thatch, aeration may be needed before the
insecticide is applied. Do this only when weather conditions are
cool and moist.
Granular formulation of insecticides are best, but solubles and
emulsions may be used. Examples of chemical registered for use
against white grubs include: * General use -- Diazinon, Dylox,
Oftanol, Sevin, Merit, Grub-X
* Certified applicators -- Triumph, Mocap., Merit
Granular insecticides should be applied with a rotary cyclone
spreader for even distribution. Calibrate and apply as stated on the
label. Irrigation following application of the pesticide is
essential. Apply an inch of water immediately, then repeat watering
every four to five days. This will move the insecticide into the
grub feeding zone. A second application is not usually necessary.
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