Question
the following is a question i have asked another expert.  he is now full.  can you help?

thank you very much for your help.  i am worried that this will continue, and i would like it to stop.  is there a way for me to send a picture?  i think if you see what i'm talking about, then you would understand a little better.  i really appreciate your help.
-------------------------

Followup To

Question -
i have researched this before asking the question, and i know it's not the "Powdery Mildew".  the blades of grass ore completly white.  Also, it has been over 100 degrees here for over 3 weeks, and over 95 for two months.  Plus, the parts of the lawn that this is occuring is in direct sunlight all day.  Also, i fertilize with the Scott's schedule.  i water in the middle of the night, and have gotten the schedule and times down so the lawn is getting properly watered.  i have also aeratted the lawn last fall, and again this spring.  is there any other thing you can think of?  One person i talked to said it could be an air born fungus/mold.  he suggested i put dish soap on it.  i did notice that the areas where this happened last year were very green this year.
-------------------------

Followup To

Question -
I live in northern Utah, near the Great Salt Lake.  I have a Kentucky Bluegraa lawn, laid ontop of some very clay-like soil.  I have had success with my lawn, but the last two years i have gotten some white patches on my lawn.  They totally kill the grass, and there is a white powder substance in it.  it looks like alkali, and the grass looks bleached.  No one can tell me what this is, how to prevent it, or how to correct it.  Can you tell me what to do?

Answer -
I suspect you are witnesing a common fungal disease called "Powdery Mildew" which is found during cool, humid weather and in shady areas. The disease is usually most common in spring and fall, but can occur anytime during the growing season.

Grass which is affected may turn yellow and die as the white powder covers the green leaves and prevent the grass from photosynthesizing.

You can test for this by rubbing a piece of grass blade between your fingers. If the white powder rubs off on top your hands then it is PM.

Mildew can be prevented by pruning trees ("limbing up") and shrubs to allow more sun to reach the grass and improve air movement.

You can also implement good sound practices to improve overall health and vigor of the grass:
- fertilize in late spring, early fall and late fall.
- mow the lawn frequently at approximateyl 2.5-3.5" tall
- water infrequently and deeply when you do water.

Hard compact soil can be loosed by core aerating the lawn every 2 years in early september. Core aerators are oversized machines which punches holes in the ground and depoit cores on top to decompose (I prefer to rake the cores).



Answer -
Just to make sure I understand:

- does this happen to the grass primarily in hot summer months ?

There are several diseases which can attack KBG in hot summer months.

One such disease is Fusarium Blight.
This disease is severe during the dry, hot periods especially following night time wetness periods. There may be light brown dead spots on the grass blades initially, and as the crown of the plant are infected, the wilting grass plants will usually turn strawcolored.

Typically the dead areas appear after the grass has been under some kind of stress for a while.

To reduce drought stress:
- adjust the mowing height upwards in mid-summer.
- Be sure to follow proper lawn maintenance practices and fertilize at the right times.
- water infrequently and deeply, such as once per week for 1 hour i/o 15 minutes every night. If you can, try to water in the morning hours so the lawn can dry right after.

Especially avoid watering late afternoon/early evening as this will lead to prolonged leaf wetness. Your best choice is in very early morning hours (4-6 am) before the main water pressure of the city starts, but just before the sun will help dry the lawn again.

Don't let thatch accumulate because fungus can grow in the thatch and then infect the grass plants when they are stressed .

I don't recommend putting dish soap on it (what good would that do, except it sometimes acts as a surfacant which helps water to penetrate heavy clay soil).

For continously infected lawns, you can apply a lawn fungicide in late spring before the symptoms normally appear, but changing lawn care routines as above is normally all you have to do.

If the "whiteness" you describe is not bleached/dead grass, but truly white (and not powdery mildew) then I suspect some kind of mold. I would have suggested snow mold, except that would be seen in spring. It could be a fungi feasting on the organic matter in the soil. This will stop once all organic matter has been decomposed

Answer
Hi Bub;
I have never seen or heard of a condition like you describe, and I have lived in almost every climate in this country.
I live in the dallase., Texas area now, and have for 40 years. We have a high humidity here, and I water early in the morning, late in the evening, and sometimes in the middle of the night.
You can't guage proper watering by time for all over, and all soil conditions.
You should always water to a depth of at least 6 inches.
I water with a soaker hose to avoid evaporation. i want all the water I pay for to benefit my lawn and garden.
If you water deeply, there will be not thatch to worry about.
Too many people don't understand what thatch is. It is dead roots that have come too close to the surface, to get water, from too shallow watering. these dead roots trap other debris and form a watertight, airtight mat. that is what kills the grass.
If you read any of my [ast answers, you know I recommend an organic program.
After over 40 years of gardening with chemicals, I final;ly tried organics, and it has solves all my problems.
What I have learnes is, chemicals CAUSE the problems,. they don't cure them.
As for the disg soap.
I know a lot of people are saying to use laundry detergent or dish washing liquid now, but think back, if you are over 40. those are some of the main things that have caused so may problems with polluting our streams.
They have very HARSH chemicals in them, and can actually KILL vegetation.
I would NOT put any of it on ,my lawn.
My best advice to you is to talk to a local nurseryman. ?They should be familiar with the specific problem you have, and know what it is and what to do about it.
Not a landscaper,,,, A degreed nurseryman.
Your County Agricultural Extention Agency will also have answers for you.
Your taxes support that department, and that is what they are there for.
Find the listing in the County Government pages of you telephone directory.
I would be very interested in knowing what you find out, about what this is and what causes it. I may get this from another questioner in your area sometime.
I searched for information, and here is the web address for a page with information on where you can call and get the information you need.
Copy and paste this address into your browser.
I am sure they will be able to tell you more about what that problem is and what can be done about it.

http://www.utahcityguide.com/home/163.asp?print=yes

Hope this helps you.
Charlotte