Thatch Control

Key Benefits

Encourages rooting into the soil, not the thatch layer
The lawn is less prone to insect and disease problems

When?

Spring or Fall
Thatch control is best performed in the spring or fall of the year, with fall being the best time of year for lawn work. The "ideal" period is August 20th through October 20th.

Core Aeration

Aeration of your lawn once (fall) or twice (spring & fall) a year will help prevent thatch buildup, improve the penetration of fertilizer and lime into the root zone, and allow the soil to "breathe". We use the machines that pull a soil plug.

Dethatching

When thatch approaches or exceeds the "threshold" of 1/2-inch thick, it becomes necessary to employ physical thatch removal. We use a flail-type machine which we found works the best.

Liming

The third step in thatch control and reduction is the light application of ground limestone. Even though your soil pH is in the correct range, thatch can be very acidic, reducing its tendency to naturally breakdown. We use pelletized lime since it makes less mess and speeds application.

for more information u could go to this site that i gave to u:
http://www.donnan.com/lawnrx.htm

for stoping pesticides hovering in ur lawn u can read this information given below :

There is never, ever, any reason to use synthetic toxic pesticides. Actually, it is more effective to use natural remedies in handling pests. You will get much better results.

Also, one should never, ever, use synthetic herbicides (nor even synthetic fertilizers.) They do much more damage than benefit. Herbicides can be extremely toxic. There are more efficacious ways to handle the lawn and garden.

Here is the deal: It is more effective, safer, less expensive, and easier to use natural remedies to handle conditions. There are so very many alternatives! Thousands! The reason natural remedies are not common-place is because their use is suppressed by the chemical boys.

I could list hundreds of natural remedies for handling pests, but I just don’t have the time to list many right now.

Here is a great start.
external link
There is an abundance of information at this site. Hundreds of alternatives are listed.

By the way, the enzyme soap mentioned works extremely well at killing pests. [use diluted one ounce to a quart] I have tried it and was amazed. Of course, the soap can not be listed as a pesticide thanks to the lobby efforts of the big chemical boys.
References :

An antidote for brown patches in the lawn because of lawn fungus try this:
In a large bucket, mix
1 tbsp baking soda
1 tbsp instant tea
1 tbsp dormant oil
1 gal warm water
Apply with a handheld sprayer, lightly spraying turf.

To get rid of moles in lawn
Mix
1 1/2 tbsp hot sauce
1 tbsp liquid dish soap
1 qt water
Pour into mole runways, & they’ll run away

Here’s a link that covers a lot of lawn topics:
http://hometown.aol.com/eilatlog/lawnol.html
References :