Integrated pest management (IPM) is an important component of any lawn care program. IPM is part of a system of keeping lawn pests at nondamaging levels by maintaining healthy plants, correctly identifying pests through regular scouting, determining action thresholds, evaluating all possible control options, and implementing selected controls. Controls used to prevent or remedy unacceptable pest activity or damage may be biological, chemical, cultural, manual, or mechanical; an organic lawn care program makes use of all of these options except chemical control.

A healthy, dense lawn is an indication of good cultural and fertility practices and is the best defense against weed problems. A lawn that is mowed at the proper height, fertilized at the correct rates and times, and irrigated efficiently will minimize infestation by weeds. Weeds in a lawn usually indicate a lack of proper growing conditions for the turfgrass. Table 7 describes weeds associated with various conditions.

If an area is heavily shaded, on a steep grade, or in a depression prone to wetness, the turfgrass cannot effectively compete against weeds that are better adapted to these conditions. If these conditions exist, consider other landscape options for the area or plan to focus more resources on caring for these areas.

If weeds occur in small numbers, use a spade or trowel to remove the plant, including the roots, to prevent regrowth. In areas of heavy weed infestation, the entire area may need to be treated and renovated. Sheets of black plastic will block sunlight and water, while raising temperatures in the soil. Covering an area for 7 to 10 days will kill most weeds. Sometimes existing turfgrass will survive. A thick layer of compost or mulch can also adequately kill weeds, but be careful not to introduce new weeds with the compost.

The best defense against most insect infestations is a healthy lawn. Healthy turfgrass with deep roots will tolerate insect damage better than plants weakened by environmental stresses. Many insects survive by eating plant tissue found in the thatch layer. Thatch buildup can be minimized by using a sharp blade to mow, mowing consistently at the proper height, and watering and fertilizing at the right rate and time. These practices will limit favorable conditions for insect habitation.

Not all insects are pests, and a healthy lawn may have active beneficial insect populations that provide essential services to the ecosystem. Learn to identify the few insects that may cause damage, and target these species with control measures when necessary. During the growing season, inspect the turf for insect activity or damage every 7 to 10 days. Focus scouting efforts in the boundary between damaged and nondamaged, or healthy, turfgrass. Before applying a control product, ensure that you have correctly identified the insect pest. Techniques for searching for insects (scouting methods) vary with different pests. Contact your local N.C. Cooperative Extension center for help or visit the NC Turf Bugs website.

Billbugs

Billbug adults (Figure 3) feed on turfgrass by puncturing holes in stems, crowns, and leaves. Larvae are small, legless grubs that feed primarily in the thatch but can move 8 or more inches deep in the soil as they grow larger. Damage appears as irregular yellow patches that grow larger over time if left untreated. Most adults are active March through April and August through September, although a small number of in-between generations can be found throughout the summer months. Larvae are generally active in June and July.

Chinch Bugs

Chinch bugs (Figure 4) insert their piercing-sucking mouthparts into plants, removing fluids that are necessary for turf health and growth. Adults are small black-and-white bugs that are most active when it is dry and hot—during the summer months. Red-bodied, first-generation nymphs are found where adults are active. Damage appears in the summer and is most severe during times of drought. St. Augustinegrass is most susceptible to chinch bug damage and will first turn yellow, then brown to white.

Scouting Method: Remove both ends from a large metal can and insert it into the turf in an area where the turfgrass is yellowed and declining, keeping most of the can aboveground. Fill the can with water. Wait 5 minutes and look for chinch bugs to float to the top. Examine three or four places in the suspected area. Parting the turfgrass to inspect the soil surface for chinch bugs also works.

Fall Armyworms, Cutworms, and Other Caterpillars

Look for an area that has noticeable bird activity, dead patches of turfgrass, or caterpillars (Figure 5 and Figure 6) feeding on leaves. Direct damage appears as “windowpaning” or sections of foliar tissue removed from leaf blades.

Scouting Method: Mark off an area of 1 square yard in a location of suspected infestation. Mix 2 fluid ounces of liquid dishwashing soap in 4 gallons of water and drench the area with the solution. Within 2 minutes, caterpillars should emerge to the surface. Kneel to observe the area closely. If no insects are found, examine other suspected areas.

Fire Ants

Fire ants (Figure 7) cause damage by constructing large mounds that are unsightly (Figure 8) and can weaken and crack surrounding cement or concrete slabs. Most important, fire ant stings are painful and can cause severe allergic reactions in some people.

Scouting Method: Look for dome-shaped mounds (not mounds with a central opening) or lines of ant hills containing several sizes of worker ants. To avoid stings, take care not to touch fire ants or disturb mounds.

Ground Pearls

Ground pearls (Figure 9) are small scale insects that appear as small cysts (pearls) or wingless, pink female adults. Ground pearl damage starts as general yellowing and then browning of turf as populations increase. Ground pearls are most common in centipedegrass.

Scouting Method: April through July, look for 1/16- to 1/8-inch pink, wrinkled insects in the root zone or near the soil surface. In summer or winter, look for 1/8-inch-long pearly cysts in the soil, up to 10 inches deep.

Mites (Bermudagrass and Zoysiagrass)

Bermudagrass mites and zoysiagrass mites are tiny, wormlike arachnids that cause occasional damage to turfgrass. Bermudagrass mites feed beneath the leaf sheath and cause rosettes, or tufts (known as witch's brooms), to form at plant nodes (Figure 10). Zoysiagrass mite feeding causes the leaf to roll in on itself from one side, creating an archlike appearance (Figure 11).

Scouting Method: Mites are almost impossible to see without a hand lens. However, because mite damage is so distinctive, it is often easy to diagnose. If unsure, consult with your local Extension center for identification or submit a sample to the North Carolina State Extension Plant Disease and Insect Clinic.

Mole Crickets

In the spring, look for distinctive tunnels in the turfgrass canopy made by mole crickets (Figure 12). In the summer, look for loose, patchy areas of thinning turfgrass.

Scouting Method: Mark off a 1-square-yard area where you suspect infestation. Drench the area with a solution of 2 fluid ounces of liquid dishwashing soap in 4 gallons of water. Insects will come to the surface in 5 to 10 minutes. If no insects are found, examine other suspected areas. This technique works best from late June to early September.

Sod Webworms

Most sod webworms vary from pinkish to yellowish to light brown. They are 5/8 to 1 inch long with thick bodies, coarse hairs, and spots on each segment. The head is yellowish brown to black. Individual caterpillars often curl into a C shape. The reddish-brown pupae are oblong and 3⁄8 to 1⁄2 inch long. The moths (Figure 13) are 1/2 to 3/4 inch long with a prominent snout. Look for brown areas in closely mown areas. Damage may resemble symptoms of diseases such as dollar spot (brown spots the size of a silver dollar).

Scouting Method: Mark off 1 square yard in a location of suspected infestation. Drench the area with a solution of 2 fluid ounces of liquid dishwashing soap in 4 gallons of water. Webworms will come to the turfgrass surface. Kneel to observe the area closely. Insects will return to the soil in 5 to 10 minutes. If no insects are found, examine other suspected areas.

Sugarcane Beetles

Scarab beetles typically cause damage in their larval form ("white grubs"). Sugarcane beetles, however, cause damage to the turf through foliar feeding as adults (Figure 14) and by tunneling in the soil, creating distinct ridges at the soil surface. Adults are active twice a year (May and September) and are recorded pests of bermudagrass, zoysiagrass, and tall fescue.

Scouting Method: Inspect managed turfgrass surrounding light sources. Adult beetles are attracted to lights at night and can be found tunneling at the base of light structures.

White Grubs

White grubs are larvae of species in the scarab beetle family, which includes green June beetles (Figure 15 and Figure 16) and Japanese beetles (Figure 17). Grubs come to the soil surface at night to feed, creating distinctive, quarter-size holes when they emerge. White grub feeding creates loose, yellow, stressed patches of turfgrass. White grubs are C-shaped larvae with red-brown heads and three pairs of legs.

Scouting Method: At the edge of an area of discolored turf, use a spade to cut three sides of a 1-square-foot piece of sod about 3 inches deep. Pull or pry the sod back like a flap. Use your fingers to sift through the soil and roots. Examine roots for chewed remnants and check the soil for grubs.

Figure 3. Adult hunting billbug.

Photo by D. Reiland

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Figure 3. Adult hunting billbug.

Photo by D. Reiland

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Figure 4. Southern chinch bug.

Photo by D. Reiland

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Figure 4. Southern chinch bug.

Photo by D. Reiland

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Figure 5. Fall armyworm caterpillar.

Photo by M. Bertone

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Figure 5. Fall armyworm caterpillar.

Photo by M. Bertone

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Figure 6. Cutworm.

DeRebus/Shutterstock image

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Figure 6. Cutworm.

DeRebus/Shutterstock image

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Figure 7. Red imported fire ant worker.

Photo by M. Bertone

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Figure 7. Red imported fire ant worker.

Photo by M. Bertone

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Figure 8. Fire ant mound.

Photo by M. Bertone

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Figure 8. Fire ant mound.

Photo by M. Bertone

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Figure 9. Ground pearl life stages: egg, cyst (pearl), and adult female in foreground.

Photo by D. Reiland

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Figure 9. Ground pearl life stages: egg, cyst (pearl), and adult female in foreground.

Photo by D. Reiland

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Figure 10. Normal bermudagrass growth on the left and witch’s broom growth habit on the right.

Photo by G. Miller

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Figure 10. Normal bermudagrass growth on the left and witch’s broom growth habit on the right.

Photo by G. Miller

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Figure 11. Arched grass blades cause by zoysiagrass mites.

Photo by D. Richmond, Purdue University

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Figure 11. Arched grass blades cause by zoysiagrass mites.

Photo by D. Richmond, Purdue University

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Figure 12. Mole cricket adult.

Photo by M. Bertone

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Figure 12. Mole cricket adult.

Photo by M. Bertone

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Figure 13. Sod webworm moth.

Paul Reeves Photography/Shutterstock

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Figure 13. Sod webworm moth.

Paul Reeves Photography/Shutterstock

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Figure 14. Adult sugarcane beetle.

Photo by D. Reiland

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Figure 14. Adult sugarcane beetle.

Photo by D. Reiland

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Figure 15. Green June beetle larva.

Photo by D. Reiland

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Figure 15. Green June beetle larva.

Photo by D. Reiland

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Figure 16. Green June beetle adult.

Photo by T. Billeisen

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Figure 16. Green June beetle adult.

Photo by T. Billeisen

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Figure 17. Japanese beetle grubs.

Photo by B. Royals

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Figure 17. Japanese beetle grubs.

Photo by B. Royals

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Prevention is the most effective way to control disease in organic lawns. Disease occurs only when susceptible plants, pathogens (organisms that cause disease), and favorable environmental conditions exist simultaneously. Choosing turfgrass suited to the region, preparing a well-drained site in a sunny exposure, and maintaining turfgrass health are the best methods to prevent disease.

Even a well-adapted turfgrass can be vulnerable to disease if the soil isn't properly prepared. Most soils in North Carolina tend to have low pH and low phosphorus levels, especially if the area was wooded right before planting the lawn.

Soils at the site should be tested early enough so that if lime and phosphorus are needed, these can be added before planting. The depth at which lime and phosphorus are incorporated influences the root depth of the turfgrass. A deep, healthy root system leads to a healthy plant that can better withstand environmental stresses, including disease.

Cool-season turfgrasses grow more effectively in the fall, which helps them resist infection from fungal pathogens. Pathogens tend to attack turfgrasses when they are stressed; therefore, most cool-season turfgrasses are more vulnerable during the summer months.

Fertilization

Disease is likely to occur in all lawns at some point during the year, but a good fertilization program can help reduce the damage. Fertilizer applications should follow recommendations for the specific type of turfgrass and be based on soil test results. Timing of fertilizer applications is crucial. Applying more than 0.5 pounds of nitrogen in June, July, and August on tall fescue can worsen brown patch (Figure 18) and gray leaf spot (Figure 19). Tall fescue should be fertilized mainly in fall and spring, but additional nitrogen during summer is often necessary. Applying less than 0.5 pounds of nitrogen per 1,000 square feet will not increase the severity of brown patch on tall fescue.

Watering

During dry weather, apply about 1 inch of water per week to turfgrass. Avoid frequent, light irrigations in the evening, as these will increase leaf wetness and create conditions favorable for disease development. Heavy rainfall often increases the appearance of disease organisms. For example, flushes of slime mold (Figure 20) are often observed after heavy rainstorms that were preceded by long periods of dry weather.

Mowing

Maintaining the proper mowing height helps control damage from disease. Most diseases will be less severe in taller turfgrass unless the higher height of cut increases canopy wetness. Also, mow turfgrass when the foliage is dry. Mowing when the turf is wet can spread disease-causing organisms from infected to healthy leaves more quickly.

Source: Diseases of Cool-Season Turfgrasses, AG-361, NC State Extension.

Figure 18. Brown patch is the most common disease of tall fescue in North Carolina. This disease can cause significant damage during the summer months and will likely require renovation if left unchecked.

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Figure 18. Brown patch is the most common disease of tall fescue in North Carolina. This disease can cause significant damage during the summer months and will likely require renovation if left unchecked.

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Figure 19. Gray leaf spot stand and plant symptoms. This disease is highly destructive in tall fescue, especially when nighttime temperatures exceed 74°F and humidity stays high for long periods.

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Figure 19. Gray leaf spot stand and plant symptoms. This disease is highly destructive in tall fescue, especially when nighttime temperatures exceed 74°F and humidity stays high for long periods.

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Figure 20. Slime mold organisms are visible but do not damage turfgrass plants.

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Figure 20. Slime mold organisms are visible but do not damage turfgrass plants.

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