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Lawn Insects: How to Control Them
Agricultural Extension Service
The University of Tennessee
PB1158
LAWN INSECTS:
How to Control Them
United States
Department of Agriculture
Originally Prepared by
Science & Education Administration
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Contents
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LAWN INSECTS: How to Control Them
Frank A. Hale, Associate Professor
Entomology & Plant Pathology
Many insects and insect-like pests damage lawns and other
turf. They cause the grass to turn brown and die, or they build
unsightly mounds that may smother the grass.
Some pests infest the soil and attack the plant roots, some
feed on the plants’ leaves and stems, while others suck juice
from the plants.
Other insects and insect-like pests inhabit lawns, but do not
damage them. The pests are annoying and some of them attack
people.
These pests can be controlled with insecticides. The recom-
mendations in this publication are applicable not only to lawns,
but also to such places as parks, roadsides, golf courses, athletic
fields, cemeteries and to the areas around airport landing strips.
However, they are not intended for the control of insects on turf
areas that might be grazed by livestock.
Pests That Infect Soil and Roots
White Grubs
White grubs are the larvae of several species of beetles. They
are whitish or grayish, have brownish heads and brownish or
blackish hind parts and are usually found in a curled position
when disturbed. They hatch from eggs laid in the ground by the
female beetles. Most of them spend about 10 months in the
ground; some remain in the soil two or three years. In mild
weather, they live 1 to 3 inches below the surface of the lawn; in
winter, they go deeper into the soil.
They burrow around the roots of the grass, then feed on them
about an inch below the surface of the soil. Moles, skunks and
birds feed on the grubs and may tear up the sod in searching for
them.
You can estimate the grub population of your lawn. Do this
in early to mid- August or in the spring after the soil warms up
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and the grubs are near the surface. With a spade, cut three sides
of a strip 1-foot square by 2 or 3 inches deep. Force the spade
under the sod and lay it back, using the uncut side as a hinge.
Use a trowel to dislodge soil on the overturned roots that might
contain grubs. Count the grubs in the exposed soil. Replace the
strips of sod. In the same way, cut strips of sod in several other
parts of the lawn, and count the grubs under each strip. To
calculate the average number of grubs per square foot of lawn,
divide the total number of grubs counted by the number of strips.
The average number of grubs per square foot is a measurement
of grub density. Economic thresholds based on grub density have
been developed to assist in the decisionmaking process of
whether to treat or not. A list of these economic thresholds is
available in the Extension PB 1342, Commercial Turfgrass
Insect Control .
The parent beetles differ in appearance, distribution and
habits. The following are important in lawns:
May Beetles . - These beetles are brown or blackish-brown.
More than 200 kinds are found in the United States. Sometimes
they are called June beetles. The adults of the species emerge in
the early spring. Most species begin emerging in May or June
and can be active throughout much of the summer. Eggs laid in
July and early August soon hatch into young, which are called
white grubs. Some of them remain in the soil two or three years
and may feed on the grass roots during several seasons.
Japanese Beetle - The beetle is about1/2 inch long and has a
shiny metallic-green
body; it has coppery-
brown wing covers and
six small patches of
white hair along each
side and the back of
the body, just under the
edges of the wings.
The adult insect feeds
on many different
plants.
Baker, J.R. 1980. Insects and related pests of shrubs.
North Carolina Agricultural Extension Service.
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Japanese Beetle / White Grub
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These insects are found mostly in the Eastern States. The
adult beetles begin to appear in late May and are active for four
to six weeks. The young are sometimes called annual white
grubs because the life cycle of the insect is completed in one year.
Asiatic Garden Beetle - The beetle is about 1/4 inch long, is
chestnut brown and has a velvety appearance. The underside of
the body is covered with short yellow hairs. The insect flies only
at night and feeds on various kinds of foliage. They are most
abundant from mid-July to mid-August. They complete their life
cycle in one year.
Oriental Beetle - The beetle is about 5/8 inch long, is straw-
colored and has some dark markings on the body. The beetles
have been recently detected in East Tennessee. At present, the
distribution of this pest in Tennessee in uncertain. They appear in
late June and July. Grubs prefer unshaded lawn and short grass.
Masked Chafers - These beetles are 1/2 inch long and
brown. They live in the soil during the day and emerge at night;
they are especially active on
warm humid evenings.
The northern masked chafer
is found from Connecticut south
to Alabama and west to Califor-
nia. In Tennessee, the distribu-
tion of the northern masked
chafer overlaps southern masked
chafer, which is common in the
Southeastern states. Masked
chafers appear in late May, June
and July and are active one or
two months.
These annual white grubs have
irregularly arranged spines on the underside of the last body
segment (raster).
Rose Chafer - The beetle is 1/2 inch long and is yellowish
brown; it has long spiny legs. Rose chafers feed on almost any
vegetation and are very destructive to roses in bloom. They
prefer areas in which the soil is light and sandy.
White grub roster location.
David Shetler
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