BROWN SPOTS IN THE LAWN AND SOLUTIONS
If we had wanted a brown lawn, we could have sodded a lawn with
the dead blocks of grass brought to Milberger's last weekend for
analysis during the KLUP-930 AM radio program! Either aliens with
small, round ships had landed in most folk's lawns killing spots
in the lawn or we have a serious problem. We decided that the
two main culprits in this spontaneous ugliness were drought and
diseases.
This is not the first week we have had this onslaught-we have
been getting questions since the first of August. So many were
received that Calvin Finch wrote an expose' which appears at:
http://www.plantanswers.com/calvin_finch_articles/brown_spots.htm
He writes: "Many lawns have brown dead looking areas. There
are many causes of the brown areas and in order to green the problem
areas, you must diagnose the cause. The brown areas usually are
caused by drought, brown patch, take-all-patch, chinch bugs or
grubs. Drought is addressed with infrequent deep watering. Brown
patch is a fungus disease favored by excessive and/or too frequent
irrigation, too much nitrogen fertilizer. Brown patch can be managed
by watering less frequently, reducing nitrogen fertilizer, and
applying a fungicide. Take-all-patch is a fungus disease that
is managed by acidification (with sphagnum peat moss, acidifying
sulfur treatments), aerating compacted soils, providing surface
drainage, deep infrequent irrigation, correcting iron and zinc
deficiencies (based on recent work by Roger Havlak), and using
a vigorous turf variety. Both chinch bugs and grubs are killed
by application of a soil insecticide."
To further refine this analysis, I will state that shallow soil
is not a good growing medium for turf grass. Most St. Augustine
planted on shallow soil and watered less than once a week with
a application of at least one inch of water WILL TURN BROWN from
lack of moisture. The exception is Floratam which is the most
drought tolerant of all St. Augustinegrass. Also, brown spots
near sidewalks or pavement are caused by drying-even if you have
an automatic sprinkler system. The water from such systems are
directed away from the sprinkler so the area immediately under
and slightly behind the system dries and dies. Also, it is very
difficult to apply enough water to the lawn in the hottest section
of the lawn which has the shallowest soil when we have a spell
of 100º F days with no rain. The dead areas are usually linear
rather than round and almost always are in full sun. The areas
can also be a spot in the lawn where the irrigation application
of water is not even. What you "should have done" was
to hand water the spots several times per week-but as Tanya Tucker
sings: "It's a little too late to do the right thing now!".
Some hand watering can prevent brown spots during periods of drought.
Brown patch disease caused by Rhizoctonia solani fungus is not
too prevalent now because the weather is dry and hot - it is more
likely to occur in spring and autumn. Brown patch fungus usually
attacks the base of the blade but seldom kills stems and roots.
The pattern is a near-circular rounded brown area with an expanding
edge. Classic spots are shaped like a donut. The green hole in
the center is formed by green blades that are re-emerging as the
grass recovers at the center of the infection. Because some people
water like maniacs (three times a week!!) during hot, dry weather,
we have actually seen brown patch in the summer. Lawns at the
bottom of the slope or lawns with high N fertilizer that are over
watered are the most likely to have brown patch. Brown patch fungus
is why we recommend that homeowners water less and only water
in the morning in the autumn. Labeled fungicides such as Turfcide
10G and Hi-Yield Lawn Fungicide Granules with terrachlor or PCNB;
Greenlight Fung-Away Systemic Granules with thiophanate-methyl,
Ortho Lawn Disease Control and Ferti-lome Systemic Fungicide with
propiconazole and Sprectracide Immunox with myclobutanil will
help stop the brown patch fungus.
Take-all patch, another fungus disease, is caused by Gaeumannoyces
graminis var. graminis. It has symptoms somewhat similar to brown
patch (irregular spots, not circular patches) but symptoms appear
mostly in the summer. Take-all patch kills roots, stems and leaves,
so the entire grass plant often dies and there is no rapid recovery.
It is difficult to manage. As with brown patch, water deeply and
less frequently, keep N fertilizer to a minimum, correct surface
and internal soil drainage, and keep mower blade in the high position.
Most fungicides do not work well, and the effect is temporary.
Texas A&M has started recommending the system discovered by
Phillip F. Colbaugh and outlined at: http://www.plantanswers.com/root_rot_fungus.htm
Basically, apply one-half inch of sphagnum peat moss over the
dead area to encourage recovery of the area. The sphagnum peat
is acid, which disfavors the fungus.
Chemicals labeled for take-all patch include Spectracide Immunox,
GreenLight Fung-Away Systemic Granules and Ferti-lome f-Stop with
myclobutanil. When I asked Jim McAfee, the common-sense Cooperative
Extension Turfgrass specialist in Dallas to comment, he responded:
"These products contains myclobutanil which is one of the
fungicides listed as having activity on Take-All Root Rot. I believe
it is as good as the other products labeled for use on Take-All.
As to which is best, peat moss or fungicide, I really can't say.
In some cases the peat moss seems to work better and then in other
cases one of the fungicides seems to work better. At $16.95 per
8 pound bag, this is very expensive. If you apply two applications
in the fall and two in the spring, that is over $68 per 1,000
square feet. You can sod cheaper than that."
Well said, which brings me to the major point of this article
on dead-spots-in-the-lawn. Many OF THESE PROBLEMS could have been
avoided if Floratam St. Augustine had been planted!!!!! See:
http://www.plantanswers.com/grass.htm
It is the most drought tolerant of ALL the St. Augustines, it
is chinch bug resistant and it is tolerant (does not show pronounced
symptoms) of Brown Patch or Take-All Patch. With this said, those
of you who have suffered the brown-spots-in-the-lawn phenomenon
this summer should follow this advice. Rent a lawn de-thatching
machine, cut and remove the dead grass areas, and re-sod with
Floratam St. Augustinegrass. Problems solved. Then next summer
when we get into a dry spell, watch for the rounding blades in
the morning on the Floratam-then water thoroughly for at least
an hour. This is a testimonial-I have had Floratam St. Augustinegrass
in my front yard for over 25 years-through the 6 degree F. temperatures
of 1983 and the 12 degree F. temperatures of 1989-and never lost
the stand AND NEVER had a brown patch circle in the yard.
When grass is rolled rather than flat in the morning water thoroughly
immediately.
One more point of interest, the ONLY organic solution which is
effective on lawn diseases is the sphagnum peat for Take-All Patch.
Sphagnum peat is not effective against Brown Patch. Lately there
have been claims made that corn meal and a garlic extract is effective.
This is absolutely false! even if these purveyors claim that a
University tested and/or recommended the product. Everyone trying
to do the "environmentally friendly-to-a-fault" thing
have been wasting their money. They would have been better off
making corn bread and using their garlic for cooking purposes!
Let me explain how these University tests and recommendations
have been misrepresented in a desperate attempt to find an organic
fungicide. The corn meal was investigated by a Texas A&M pathologist
as a way to produce parasitic fungi used to control a fungus which
occurs on peanuts if not planted in a crop rotation with corn.
This is a very specific and very unusual parasitic fungi relationship
which DOES NOT translate as a control for every other fungus on
earth! The same "leap of knowledge" was used years ago
when it was found that a sugar concentration in a solution would
kill soil nematodes in a test tube because of osmotic pressure
differentiation. The resulting organic nematode control was to
add sugar to the soil!
The old test tube and petri dish has also generated another
massive outlay of misinformation about garlic extract. Another
University did some studies in petri dishes exposing several soil
pathogenic fungi types to garlic extract as well as THE EVIL PETRO-CHEMICAL
products currently being used. GOOD NEWS!!!!!!!! The garlic extract
was as good if not better than the chemical products. I imagine
salt would have also been effective-in fact, I know it would.
Years ago Texas A&M stated in a publication that the addition
of salt to a soil would reduce the occurrence of cotton root rot
fungus. Who could tell? The plants wouldn't grow in the salty
soil anyway!!!
I consulted Dr. Larry Barnes, Texas A&M pathologist about
this University test on garlic extract. He indicated that the
petri dish test is only an indicator of what might work in the
soil and the petri dish test alone SHOULD NEVER BE USED as a positive
indicator of effectiveness of a product. Do you wonder why further
testing in field conditions have not been performed? Because the
product distributors do not want to take the chance of failure.
So if you want to waste money on a "snake-oil" product
that hasn't ever been statistically shown to be effective in field
conditions just for the sake of organics, step up to the counter-they
will be more than glad to take your money!
For more about the importance of fungicides-chemical or not--
read on:
Safe, abundant, high quality food is the rule rather than the
exception in America. It's a standard which consumers demand.
Food producers rely on a variety of agricultural technologies
to ensure that America's dietary needs remain affordable, nutritious
and readily available on grocery store shelves.
One of these agricultural advances, which has helped make U.S.
consumers and growers the envy of the world community, is a family
of agricultural chemicals known as fungicides.
Fungicides are chemicals which shield crops and foods from fungus.
They perform as "medicines" for plants. Fungal diseases,
if left unchecked, rob crop yields and cause rapid spoilage of
fresh produce.
*Fungicides help growers provide top quality food and feed grains
to U.S. consumers and the world.
*Fungicides provide consumers with fruits and vegetables at
the peak of freshness and nutrition.
*Fungicides enable importation of a variety of fresh produce
which is unavailable or in limited supply from U.S. growers, such
as bananas.
*Fungicides help U.S. producers provide wheat, corn and other
grains to food-needy nations.
*Fungicides help maintain America's pre-eminent position as
an efficient producer of food and fiber for domestic and foreign
consumption.
Some fungicides are applied as a seed treatment, effectively defending
the germinating seed from infection. Virtually all seeds for U.S.
corn and wheat crops and nearly one-third of soybeans are treated
in this manner. Other fungicides are applied to the growing crop
to protect the leaves and fruit. Still others are used to guard
against fungal-borne decay during shipping and storage of harvested
crops.
Fungal disease, unlike many human ailments, is not curable after
detection. Crops are constantly threatened by a variety of fungal
organisms. If left unprotected, crops can be ruined, harvests
devastated. Hence, the recommendation made when tomato plants
have set an abundance of marble-sized fruit, to begin a preventative,
prophylactic fungicide spray every 7 days with a product containing
chlorothanol such as Daconil. This application such be judicially
applied during periods of wet (rain or heavy morning dews) weather.
Once the symptoms (plant foliage yellowing and dying from the
bottom of the plant upward) begin, leaf surface, and consequently
plant production, has been damaged.
What would happen if growers stopped using fungicides? Recently,
a noted Washington, D.C., economics firm explored this question
in detail. Its authoritative report found broad implications of
restricting fungicide use.
Although fungicides account for only 7.4 percent of all crop
protection chemicals sold in the United States, eliminating their
use would:
-reduce, drastically, the availability of foods necessary to
maintain a healthy diet;
-sharply boost food prices, (fresh produce would jump 34 percent),
making a wide variety of produce unaffordable to many lower-income
Americans and causing costly reductions in the supply of many
processed foods, such as peanut butter, vegetable oils, prepared
cereals and canned food;
-increase the threat of natural toxins in foods;
-slash U.S. fruit, vegetable and peanut production;
-and wipe out nearly a quarter million on-farm jobs with negative
ripple effects among rural community businesses.
Imagine an America where fruits and vegetables were constantly
in short supply...an America where fresh produce was so scarce
that higher prices made them unaffordable to the average consumer.
Unimaginable? Such a situation could exist if fungicide use was
halted. Fruit and vegetable supplies would drop by 24 percent.
With the help of fungicides, America's growers have been able
to nearly double apple and peach production and increase by one-third
supplies of strawberries, grapes and tomatoes. The consumer benefit:
greater selection, lower cost, less need for imported produce.
Fungicides also are responsible for safeguarding our nation's
almond and peanut crops. Otherwise, production of these two crops
would be nearly non-existent. Yields for everything from potatoes
and carrots to lettuce and onions would plummet in the absence
of a guard against a wide variety of fungal disease.
Many imported products such as bananas and other tropical crops
which are dependent on fungicides for production would be either
unavailable or so expensive as to be luxury purchases for most
consumers.
By sustaining production, fungicides help hold down food costs.
The price tag for apples and carrots would nearly double without
fungicide use, while the cost for potatoes, peaches and tomatoes
would climb by more than 36 percent. Consumers would pay substantially
higher prices for lettuce, beans, strawberries and grapes. Almond
prices would jump more than 136 percent, and peanut prices would
rise 68 percent.
Fungicides help maintain a variety of healthful food choices.
Fruits and vegetables are more than just good for you. Studies
and recommendations, such as those by the National Research Council,
National Academy of Sciences, show that diets emphasizing fruits
and vegetables can significantly reduce the risk of coronary disease
and some types of cancer.
In the absence of fungicide use, many Americans would be forced
to turn away from or limit their consumption of fresh fruits and
vegetables because of higher price tags, limited supply and lower
quality produce. Low-income consumers would be especially impacted
-- both economically and from a health-risk perspective.
Also worth noting is that many crops grown without fungicides
tend to produce greater amounts of natural toxins produced by
uncontrolled invading fungi, or infected produce. In high concentrations,
these toxins can raise more serious health-related questions which
override the risks of fungicide residues.
We are fortunate to live in a nation where food is plentiful.
Indeed, the United States continues to set the global standard
for food safety, afford ability and nutrition. U. S. growers backed
by proven technologies such as fungicides, and guided by consumer
needs for healthful diets sustain the reality and fulfill the
promise of safe, abundant and nutritious food for generations
to come.
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