Insect Pests of Home Lawns

Beverly Sparks and Will Hudson, Extension Entomologists

Importance of Pests

Home lawns in Georgia are commonly infested with insects and related arthropods. Most of these creatures go unnoticed by the homeowner, however several species cause serious damage to turfgrass. These pests can be divided into two groups based on where they are found: soil inhabitants and thatch inhabitants. Both groups can severely damage turf. A knowledge of pest biologies, life histories and habits is needed before effective control programs can be implemented.

Nature of Damage

Damage to turfgrass from insect pests takes many forms. Feeding by soil-inhabitants such as white grubs, billbugs, and mole crickets usually shows up as wilted, dead or dying grass. Sod may be disturbed in areas where wildlife or pets dig up soil-inhabiting pests. Damage to turf by thatch inhabitants such as sod webworms, armyworms and cutworms is apparent when grass is cut off close to the ground. Damage by chinch bugs and spittlebugs, also thatch inhabitants, is similar to damage caused by soil inhabitants. Irregular spots of yellowish turf and dead spots may occur where chinch bug or spittlebug infestations go uncontrolled.

Due to the variation in symptoms of damage, insect pests must be correctly identified before the appropriate method of control can be chosen. Knowledge of the biology and life cycle of correctly identified pests is the key information needed to design an effective control program. Your local County Extension agent or other turf professional can provide assistance with identification of turf pests.

Pests - Identification, Life Cycle and Diagnosis

Soil - Inhabiting Insects

• Mole Crickets
• White Grubs
• Billbugs

• Spittlebugs
• Chinch Bugs
• Sod Webworms
• Armyworms
• Cutworms

Control of Major Turf Pests

In Georgia, most insect pests of turf can be controlled when damaging populations are found. However, remember the first step to management of lawn pests is prevention. Good cultural practices are essential to prevent insect pests from destroying turf. Use recommended methods of fertilization, watering, mowing, etc., to keep grass healthy and growing vigorously. A healthy lawn can tolerate light insect infestation and damage is masked or overcome by rapid growth of plants. Current recommendations for growing and maintaining healthy turf are available from your local County Extension office.

Thatch Removal

Thatch removal is one means of preventing chinch bug and spittlebug outbreaks. Heavy thatch accumulation provides an ideal environment for these insects. Thatch also interferes with delivery of insecticides to the insects.

The next step to management of turfgrass pests is early detection. This is the weakest link in pest management programs for lawns as most insects go unnoticed until after their damage is observed. Two techniques useful in detection and monitoring insects in turf grasses include floatation and irritation. Floatation uses water to detect the presence of chinch bugs. Remove the bottom from an oil can, coffee can, or similar container. Push the can two to three inches into the turf in an area of suspected chinch bug infestation. Fill the can with water and hold the water level above the grass by adding additional water for about five minutes. If chinch bugs are present they will float to the top. (Sample several spots at the edge of the area where you suspect chinch bugs are damaging grass to increase the chances of finding the insects.) The irritation method is particularly useful in detection and monitoring of mole crickets, cutworms, armyworms or sod webworm infestations. Lemon dish washing detergent is a good inexpensive irritant. Mix the detergent with water and pour over a turfgrass area. The detergent irritates sensitive soil-inhabiting pests causing them to quickly come to the surface. Use one ounce liquid detergent per gallon of water. Use one gallon of water to sample a one square yard area of turfgrass. Pyrethrin is also a good flushing agent when used at a concentration of one to three percent in water.

Proper Selection of Control Materials

Materials labelled for insect control on home lawns are available in several formulations: baits, emulsifiable concentrates, wettable powders, soluble powders, and granules. The formulation selected, as well as the specific insecticide chosen, determine the level of control. For example, bait formulations are superior in spring and fall for mole cricket control, whereas summer treatments with sprays or granules give better control. Spray applications of insecticides provide the highest degree of control within the first 24 - 48 hours after application. In general, the initial control with granular treatments is less than that from sprays. Insecticidal activity begins only when the granule absorbs moisture and releases the insecticide. For specific insecticide recommendations on turf consult your County Extension Agent.

Correct Application Methods

Application methods are extremely important in turf insect control. The homeowner may use the most effective insecticide available, but if the method of application is poor, the level of insect control will be disappointing.

To control insect pests living in the soil, the target zone for the insecticide should be the soil at the root zone. Liquid and granular formulations must be watered in sufficiently to move insecticide off the surface, through thatch, and to the root zone. In lawns with heavy thatch it is of benefit to dethatch the lawn prior to insecticide application.

To control surface feeding pests, the target zone for the insecticide should be the leaves, stem and thatch. Spray formulations leave residues that remain on the surface and provide control of thatch inhabitants.

The objective of spray applications is to apply insecticides to the area where the target pest lives and eats. The volume of spray applied should be adequate for uniform coverage of leaves, stems and thatch. Too little volume will result in poor coverage and reduced control. In general, a minimum of 1 gallon of finished spray per 1000 sq. ft. is required for adequate coverage. Use coarse sprays to reduce drift and penetrate foliage.

Water and Irrigation Requirements

Quality and well as timing and quantity of water are additional factors involved in achieving adequate control of insects with insecticide applications. The pH of water used to mix insecticides should fall into the slightly acidic to neutral range. Water with a high pH (greater than 8) can cause rapid breakdown of some insecticides.

Timely use of irrigation can help get best results with insecticides for soil-inhabiting pests. During dry weather the turf should be irrigated prior to treatment. This will help the insecticide to penetrate grass blades and dry thatch. Follow label directions in regard to irrigation procedures following application.

Granular insecticides should be applied to dry turf. Granules will stick to wet grass blades and may not penetrate the thatch layer and reach the soil. Rapid watering-in is desirable with granular formulation, but it is not as critical as with liquid materials. At least one-half inch of water should be applied to activate granular materials and place it in contact with pests located at the surface. An additional half-inch to one inch of irrigation following treatment will carry the insecticide down through thatch and into the soil to the root zone. Delays in watering-in control materials will greatly reduce the chances of good control.

Bait formulations are used to attract soil-inhabiting pests to the turf surface where they consume a toxic dose of insecticide mixed in the bait. These materials will be ruined by rainfall or irrigation. Time of bait treatment is also critical. For night-feeding pests such as mole crickets and cutworms, baits should be applied late in the day.

Trade and brand names are used only for information. The Cooperative Extension Service, The University of Georgia College of Agricultural and Environmental Sciences does not guarantee or warrant the standard of any product mentioned; neither does the use of a trade or brand name imply approval of any product to the exclusion of others which also may be suitable.

Bulletin 1094/May, 1993

The University of Georgia and Ft. Valley State College, the U.S. Department of Agriculture and counties of the state cooperating. The Cooperative Extension Service offers educational programs, assistance and materials to all people without regard to race, color, national origin, age, sex or disability.

An Equal Opportunity Employer/Affirmative Action Organization Committed to a Diverse Work Force

Issued in furtherance of Cooperative Extension work, Acts of May 18 and June 30, 1914, The University of Georgia College of Agricultural and Environmental Sciences and the U.S. Department of Agriculture cooperating.

Gale A. Buchanan, Dean and Director

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