Almost every Saturday morning
on my show I will get the inevitable turf grass question,
what is wrong
with my lawn? Why? Well remember that our lawns make
up a very large proportion of our garden. This large area is also
a monoculture of various turf grass species and even
the most novices of gardeners easily notice any
small discrepancy in colour, height or texture. If the question is not about a turf
grass disease or weeds then it will be about insects. The question
is by far almost always about those turf grass thugs- insects.
Insects are always feeding on our lawns. This is natural but when
a turf area is stressed by adverse environmental conditions then our
turf grasses can not grow faster than the destruction caused by
the insects. The other possibility is that the insect population
has just exploded because their environmental conditions are perfect.
are the top seven wanted to be dead turf grass thugs:
larvae feed on the shoots of the turf grasses. They
are nocturnal feeders that produce somewhat circular
patches of defoliated turf. The moths fly at night
and are attracted to light sources. The females begin
depositing eggs on area just
above they our turf grass in May.
The eggs upon
hatching as larvae, start feeding immediately. The armyworm
larvae migrate from place to place as a large group
fact they will even feed on cloudy dull days as well as at night.
Normally though they can be found hiding in the thatch layer during
the day. Armyworms may have as many as three generations per
Apply a turf grass insecticide at the first sign of the tattered grass.
The Bill Bug
larvae burrow into the stems where there
is moisture. They then feed on the turf grasses roots,
rhizomes and shoots puncturing the plants tissues as they
go. As the turf grass' stems and crowns die they form
irregular brown patches. The Bill Bug adults feed on the stems
leaf blades causing only minor damage. In late May the
females deposit their eggs in the
just above the crown. Their
larvae appear in late
June feeding inside the turf grass' stem. It is at this
stage that the most damage is
Apply a soil insecticide (Diazinon, Chlorpyrifos or
Merit®) in May.
larvae of the European Chafer feed on the roots and rhizomes
of your turf grass in the midsummer. The turf grass roots are
unable to regenerate at this time and thus creating irregular brown
patches. The European Chafer has a one
year life cycle and swarm in the trees in late
to early July. To identify them look at the arrangement of the
spines on their raster. This arrangement will be two rows of
spines that diverge near the tip of the abdomen. Their threshold
is 5-10 grubs per .1 square meter on non-irrigated turf. 10-20
grubs per .1 square meter on irrigated turf.
Merit® in spring or Chlorpyrifos in August.
Life Cycle of the Annual White Grub
characteristic "C" shape typical of all of the white
grubs. Their life cycle is at best irregular. There maybe or
two generations of grubs per growing season or as few as one generation
every three years. The June Beetle feeds on the foliage of your
trees and shrubs. It is often seen flying around your lights at
night. To identify them look at the arrangement of the spines on
their raster. The spines are almost parallel. Their threshold
is 3-5 grubs per .1 square meter before control is necessary.
A soil insecticide (Chlorpyrifos or Merit®) during the growing season.
The Hairy Chinch
Bug sucks the juices from your turf grasses.
This weakens them to form large irregular yellow to brown
patches. The Nymphs are small, red and first seen in May.
The Nymphs emerge in May and June. They go through five stages
(instars) in approximately thirty days. A second
develops in September. As the Nymphs emerge in May and June.
through five stages
(instars) in approximately thirty days. A second generation
develops in September.
Apply Carbaryl (Sevin), Chlorpyrifos, Diazinon or Merit® in early July.
The larvae of the
Sod Webworm feed nocturnally on the grass shoots. They will consume the grass right down to the
soil level leaving large irregularly shaped brown patches .
The Sod webworm adults are small buff coloured moths. They
construct silk-lined tunnels through the thatch layer and down
into the soil. The moths hide in the grass during the day
and usually fly at dusk or when disturbed by foot traffic.
They will fly in a zig zag pattern close to the
Apply Carbaryl (Sevin), Chlorpyrifos, Diazinon or Merit® when you first notice
them. Do not water or mow the lawn for several days after you apply one
remember the pesticide label is a legal document.
follow the label directions.
in doubt always ask a professional.
can only be applied by a licensed professional
following information should help you to minimize your turf disease and
should provide adequate, but not excessive fertility.
Excessive nitrogen application, particularly in the spring results
in lush , succulent growth which is more susceptible to diseases and
insects. An Autumn application of a significant portion of the
fertilizer is highly recommended. A fertilizer application in
hot weather may also burn the turf and be wasteful if the turf is
not actively growing to utilize the nutrients.
the turf thoroughly in the early morning hours to encourage deep
rooting. This makes your turf less susceptible to
drought. Watering in the evening will only encourage diseases.
turf early in the day, as often as necessary, with a sharp lawn
mower. Using a dull mower and evening mowing leaves open
wounds which are more readily infected by disease causing
or remove grass clippings if thatch build up is a problem. Do
not remove more than one-quarter to one-third of the leaf surface in
one mowing. Excessive removal reduces the turfs ability to
regrow after mowing especially in the summer heat. This will also
make it more vulnerable to disease and insects.
excessive thatch. This layer of brown accumulated organic
material found between the leaves and the soil should be less than
2.5 centimeters thick. You can remove it by raking it
out or by composting it on your lawn. Composting is done by
providing adequate moisture, nitrogen and cutting your turf
frequently so that the clippings are very small. This will
allow them to decompose quickly.
type perennial rye grass varieties such as Barry, Blazer, Fiesta,
Fiesta II, Manhattan II, Omega II, Palmer and Yorktown are among the
many varieties that are recommended for over-seeding problem turf
Please note that
perennial rye grasses look very different than other turf grass
varieties. Therefore you should over-seed the entire turf
area. Do not seed just the dead areas.
producing turf grass varieties will discourage those insects that
feed at or above the soil surface.
reduce the insect populations on your turf at or above the soil
surface you can use an old vacuum cleaner to vacuum up the
sandals are available for you to wear. You then walk all over
your turf with them. This will aerate the turf and puncture the
white grubs below the soil surface.
nematodes are also available to be watered into the
turf. They will then hunt out the white grubs and kill
U.S.A. there is a product called milky spore available which infects
the white grub and kills them. This naturally occurring
disease is resident in the soil for many years.
are also a natural predator of turf grass insects so encourage the
birds. (see my
method that you choose to control your turf grass problems is up to you.
You will find that not just one method will solve your problem(s).
Choose the best combination of methods for your needs and level of
Chlorpyrifos IS NOW BEEN REMOVED FROM THE MARKET AND DIAZINON WILL
BY 2003. Sevin and Merit®
is all we have at the moment