The
key to proper pest control in lawns is based on good lawn maintenance.
A well maintained and healthy lawn can avoid many diseases and problems
caused by insects. A vigorously growing lawn crowds out weeds and
therefore reduces the need for pest control. FIVE
STEPS TO A HEALTHY LAWN:
- Plant
adapted grasses-
Plant types of grass that are adapted to your region and the conditions
that exist in your lawn. In the northern United States, where
Kentucky bluegrass is widely grown, many different varieties are
available.
Perennial ryegrass and turf-type tall fescues are suitable for
sites where lawn watering is limited. Warmer weather areas of
the country would do better using other types of grasses such
as Bermuda grass or zoysia grass (see "Greener Grass" for more
on types of lawn grasses)
- Fertilization-
Provide fertilizer as needed for healthy plant growth. Avoid high
application rates of fertilizers, particularly quick release nitrogen
fertilizers, at any single period. High rates of nitrogen over
stimulate shoot growth at the expense of root development. Over
stimulated plants are more susceptible to many lawn diseases.
They also require more watering and mowing. For most lawns, fertilization
every two months during the growing season works well (see How-To
article #3095 "Lawn Fertilizers" for more information on fertilizers)
-
Deep root growth-
Infrequent deep watering of 1/2-1 inch is better than frequent
shallow watering. Water early in the morning. Leaf blades will
dry quickly afterward which helps reduce leaf diseases.
- Mowing-
Use a sharp mower blade to avoid ragged cuts. Never "scalp" the
lawn since this increases exposure of the grass crowns to temperature
extremes and discourages root growth. As a general rule, mow at
a height of about 2 1/2-3 inches, never removing more than one-third
of the leaf area.
Note: Mowing heights may be increased some what during
hot months, reduced slightly during cooler periods. Lawn clippings
do not need to be removed if they are short. As the clippings
decay they release nutrients and reduce fertilizer needs.
- Aeration-
Periodically aerate the lawn to improve compacted areas or places
where thatch (accumulated dead plant debris) blocks water and
nutrients. You can use either a motorized or a foot-press type
of aerating machine.
WEED
CONTROL:
Annual (single season) weeds such as crabgrass, chickweed, and spurges
can be controlled by use of pre-emergent herbicides, which kill
germinating seeds or newly sprouted weeds. Since they do not affect
older plants, these herbicides must be applied before the weed seeds
have sprouted.
Post-emergent
herbicides kill weeds that already exist in lawns. Many of these
herbicides are selective and only kill certain types of plants.
For example, MCPP and 2, 4-D are selective herbicides that only
kill broadleaved plants such as dandelions, chickweed, and thistle.
Other herbicides, such as fluazifop-butyl (Grass B-Gon) only kill
grasses. In addition, there are many non-selective herbicides, such
as glyphosate (Round-up, Kleen-up, etc.) which kill most plants.
It
is often best to spot treat individual weeds by digging with a hand
weeder or applying herbicides.
Dandelions-
Although the dandelion was first brought to North America as a food
plant, most people today do not appreciate its virtue. It is the
weed most homeowners fight the hardest. Dandelions are perennial
weeds that live for several years once they have become established
in a lawn, their bright yellow flowers first appearing in spring.
Post-emergent
herbicides such as 2, 4-D, MCPP, MCPA, and dicamba can kill dandelions
during any period when the plants are actively growing, but are
particularly effective in the fall.
Crabgrass-
An annual weed that grows from seeds produced in previous years,
crabgrass seeds sprout early in the spring and continue to sprout
through early summer. Pre-emergent herbicides, such as pendimethalin,
must be applied before seeds sprout in order to be effective. (First
bloom of forsythia is a common natural indicator for application
timing in many areas.)
Post-emergent
herbicides, such as MSMA can also suppress crabgrass. However, this
treatment can cause desirable grasses to discolor temporarily, particularly
if not used carefully.
Chickweed-
Like crabgrass, chickweed moves aggressively into areas of the lawn
that have thinned. However, these plants sprout in the fall and
the plant grows during the winter. Small white flowers begin to
be produced in early spring along with seeds.
Post-emergent
herbicides such as MCPP can kill chickweed plants, particularly
if they are small. Pre-emergent herbicides, such as DCPA and benefit,
applied in fall can prevent new seeds from germinating.
