Chinch bugs are insects less than a 14 inch in length with thin, black bodies and white wings. A lawn infested with chinch bugs will have irregularly shaped patches of dead grass, surrounded by a ring of yellowing grass. This differs from fungal infections in that these patches will not be an even circular shape. Chinch bugs feed on grass roots and are one of the largest threats to your lawn.
Thatch is the grass left in your yard after months or even years of repeated mowings. It creates a thick, protective layer that chinch bugs often hide under. Rake it up and you will encourage birds and other natural predators to go rooting for chinch bugs. Make this more effective by spraying the lawn with a mixture of dish soap--not antibacterial soap. The soap acts as an irritant and will drive chinch bugs to the top of the grass to dry themselves. Then, more of them will be vulnerable to predators. Another method to home treat chinch bugs is to drown them. If your lawn is of a type capable of withstanding flooding, overwater the grass until it's so soaked that the chinch bugs either drown or become more susceptible to disease.
Aside from birds, there are other insects which are natural predators to chinch bugs that will do no harm to your yard, if introduced. This is an alternative to pesticides, which can disrupt the balance between harmful and beneficial insects and simply exacerbate the problem. Big-eyed bugs (Geocoris) are a genus of insects roughly 1/6 inch long with fat bodies that closely resemble cicadas. They do not eat plants, and instead prey on other insects commonly found in grass. Note that this also includes other beneficial species of insects. Minute pirate bugs (Xylocoris) are used to protect cornfields from different species of root and earworms. They have triangular abdomens, flat bodies, black carapaces with white streaks and a surprisingly painful bite for an insect no longer than a fingernail. They are not venomous, nor do they carry disease, so they pose little more than an annoyance to people.
Diazinon is generally considered to be the most effective pesticide. It kills quickly and has a short half-life, so the lawn is free of residue no more than six weeks later. The problem is that it's a nerve toxin, which can kill humans and pets, if inhaled, absorbed through the skin or ingested. To that end, you cannot buy it any more, though it's still legal to use if purchased before 2004. Acephate is commonly marketed under the name Orthene. It is an insecticide which operates on the same properties as diazinon, but has an even shorter half-life and is generally considered more manageable, leading to fewer health risks.