Yellow Patches in the Lawn and Dead Trees

Water

• Most established trees are fairly drought-tolerant although most grasses need at least 1 inch of water per week. However, excessive drought can damage or kill trees and cause yellow spots in the yard. Heavy, poorly-draining soil can also cause tree death and yellow spots in the yard. Plant roots cannot get oxygen in wet soil, and the plant eventually drowns.

Disease

• If you've ruled out growing conditions, look at trees and grass separately to identify the cause of the problem. Symptoms of tree disease include leaf spots or yellow leaves, cankers or bumps on the trunk, leaves or branches, and blackened twigs and limbs. Grass diseases usually cause yellow spots to form in a specific way, such as the crescent shape commonly observed when Fusarium wilt is present.

Pests

• Boring insects, such as the Emerald borer that attacks ash trees and the pine bark beetle, can kill trees. Look for signs of insect infestation, such as boring holes and piles of sawdust at the base of the trees. Grubs, aphids and other insects cause yellow patches or wilting in lawns. Cut the bottom off of a coffee can and place it over the soil. Fill the coffee can with 1 gallon of water mixed with 1 tbsp. liquid dish soap. The water will cause insects in the soil to float to the surface where you can see them. Separate the grass and inspect the roots for tiny, white grubs. These insects eat the roots away, causing the grass to yellow and die.

Environmental Problems

• Environmental causes are usually to blame for widespread death of landscaping plants. Leaks in a septic system or gas line can cause toxins to leak underground. Herbicides and other chemicals may drift, causing plant damage. Trees and grass may not survive extremely cold or hot weather.