Disruption of Soil
Symptom: Hills, piles or structures of loose dirt on turf
Possible cause:Ants

Symptom: Mounds up to 18 inches tall with no visible entrance(s) on mound with ants emerging in mass when disturbed
Possible cause: Red imported fire ants

Symptom: Small mounds with rims around single central entrance holes and presence of small (3/16 in.) grayish black ants
Possible cause: Pyramid ants

Symptom: Many hills of course soil with central exit holes and presence of large (3/8 in.) red-brown ants with spines on the thorax
Possible cause: Texas leafcutting ant

Symptom: Flat cleared areas up to 3 ft. in diameter made of course soil particles with a single central exit hole and with the presence of large (3/8 in.) reddish-brown ants with squarish heads and no spines
Possible cause: Red harvester ant

Symptom: Trails of raised, loose dirt through turf roughly 1/2 inch wide in an “S” shaped pattern
Possible cause: Mole crickets

Symptom: Small piles of dirt “pellets” (1/8 in.) scattered through thatch
Possible cause: Earthworms

Symptom: Earthen chimneys with center holes (about 1/2″ diameter)
Possible cause: Crawfish

Symptom: Small piles of loose dirt associated with exit holes
Possible cause: Green June beetle larvae

Symptom: Round holes (up to 1/2 in. diameter) in soil
Possible cause: Digger wasp nests or cicada exit holes

Direct damage to grass causing yellowing or plant death:
Symptom: Grass blades chewed or missing
Possible cause: Grasshoppers [PDF]

Symptom: Presence of gray-brown caterpillars up to 1 in. long with an inverted cream-colored “Y” on the fronts of the head capsules
Possible cause: Armyworms

Symptom: Presence of gray-brown caterpillars up to 1 in. long that curl into a tight “C” position when disturbed
Possible cause: Cutworms

Symptom: Presence of translucent greenish caterpillars up to 3/4 in. long with black raised spots on each body segment
Possible cause: Tropical sod webworm

Symptom: Roots missing and presence of cream-colored “C” shaped grubs with three legs on body segments behind brown head
Possible cause: White grubs

Symptom: No tissue removed, with presence of orange, white and black nymph and adult stages of bugs up to 1/4 in. long
Possible cause: Chinch bugs

Symptom: No tissue removed, but with “galls” or globular objects (scales) in the root zone
Possible cause: Rhodes grass scale or ground pearls

Symptom: No tissue removed, but with shortened internodes producing a typical rosetting and tufted growth, or a “witch broom” effect; grass may be very yellow or whitish in appearance with no insects visible to the naked eye
Possible cause: Bermuda grass (stunt) mites or buffalo grass (stunt) mites

In addition to the links above, try these related links or search the Department of Entomology and Extension Entomology online publications:

B-6110, Common Caterpillar Pests of Vegetables
L-2061, House-infesting Ants and Their Management
Factsheet #013, Texas Fire Ant Identification: An Illustrated Key [PDF]
AggieTurf
Behavioral and Community Interaction of Phorid Flies and Fire Ants – University of Texas