Arthropod pests of turfgrass are varied and sometimes difficult to manage. Damage caused by arthropod pests can be mistaken for disease, drought stress, or other environmental disorders, so proper identification of the causal agent is an essential component of integrated pest management (IPM) of turfgrass pests. Chemical control should not be used as a substitute for good horticultural practices or as “preventative insurance” because it is usually not economically or environ-mentally justifiable. Careless pesticide use also can encourage the development of insecticide resistance. Many turfgrass pest problems can be avoided by following good horticultural practices such as selection of Oklahoma-adapted varieties that are resistant or tolerant to commonly encountered pests. Other cultural control methods include effective thatch management, mowing heights and frequencies that do not stress turfgrass, proper fertilization and irrigation, and weed and disease control. Keep in mind that insecticides with a broad spectrum of activity can harm more than the intended target pest, including pollinators and natural enemies (predators and parasites) of pests. Whenever possible, choose a “reduced risk” insecticide that is not harmful to the environment or non-target organisms when used correctly. Rotate among different pesticide classes to delay or prevent resistance among target pest populations. Chemical recommendations made within this publication are current as of the revised date and are intended for commercial use by golf course superintendents, lawn and landscape professionals, and parks and recreation managers. Always check the insecticide label for the most current application rates and methods, and any use restrictions. Refer to the following OSU publications for additional information.

• E-1020: A Pocket Guide to Oklahoma Turfgrass Diseases, Insects, and Other Disorders ($5 and available through Oklahoma Cooperative Extension Service)
• HLA-6418: Selecting A Lawn Grass for Oklahoma
• HLA-6419: Establishing A Lawn in Oklahoma
• HLA-6420: Lawn Management in Oklahoma
• HLA-6600: Turfgrass Management of Bermudagrass Football Fields
• HLA-6601: Broadleaf Weed Control for Lawns in Oklahoma
• HLA-6604: Thatch Management in Lawns
• CR-6605: 2014 Oklahoma Turfgrass Sod Source Directory
• HLA-6608: Managing Turfgrass in the Shade in Oklahoma
• EPP-7324: Large Patch (Zoysia Patch) of Warm-Season Turfgrasses
• EPP-7658: Dollar Spot of Turfgrass
• EPP-7665: Spring Dead Spot of Bermudagrass

^† Restricted Use Pesticide

Control Notes for Imported Fire Ants

Individual mound treatment

Generally, non-chemical methods are not effective against fire ants. Digging or tilling up mounds simply moves them around. Boiling water (3 gallons per mound) may be effective for treating individual mounds, but it must be done carefully to avoid killing plants and not suffering from serious burns.

Best control has been achieved with chemical treatment of nests and surrounding areas. The best time to individually treat mounds with contact insecticides is on a sunny morning after a cool night, when ants are near the surface of the mound. Such treatments can be accomplished with drenches, surface sprays, granules, or baits.

Most mound drenches involve mixing the insecticide in 1-2 gallons of water. The treatment should be applied to the mound with a watering can that sprinkles the treatment on the mound much like a gentle rain. If the drench begins to cause the dirt on the mound to run off, stop and allow the liquid to soak into the mound, then resume drenching until all of the liquid is used.

Dust formulations like Pinpoint can be sprinkled on and around the mound, according to label instructions. If the label states that the treatment should be watered in, then do so with a watering can. Other products may state that the products should not be watered in.

Baits

Most ant baits contain a slow-acting insecticide, such as an insect growth regulator (IGR) that can be taken back to the mound and fed to other members of the colony, including the queen. They can be applied as a broadcast, or used as individual mound treatments. If they are used to treat individual mounds, the bait should be placed about 1-3 feet around, but not directly on, the mound.

Baits work best if applied when workers are actively for-aging. This can be determined by leaving some greasy food, such as some chunks of tuna fish, or hot dog pieces, potato chips, or peanut butter near a mound and checking if for ant activity after 15-20 minutes. During the summer, worker ants forage at night and are actually inactive during the day. The best time to apply baits is in late afternoon or early evening. Moisture and rain will dissolve bait particles, so use baits only when grass and soil are dry, and no rain is expected within several hours after treatment.

A proven approach for managing red imported fire ants is to make a broadcast bait application in late spring when soil temperatures are above 70 degrees F and ants are actively foraging. This bait application should be followed up by treating individual problem mounds about 1-2 weeks later. For best results, always avoid disturbing the mound before or during treatment since it will cause the ants to move away and avoid the chemical.

For downloadable documents on red imported fire ant control options and more information on red imported fire ants in Oklahoma, check the Oklahoma State University Department of Entomology and Plant Pathology’s Fire Ant Website.

* The numbers associated with the pesticide class column were developed by the Insecticide Resistance Action Committee, (IRAC) in 2005. It is intended to help in the selection of insecticides for preventative resistance management. If you make multiple applications for a specific pest or group of pests during a growing sequence, simply select a registered insecticide with a different number for each generation (14-21 days). You can rotate within the same number if more than one subgroup is available (Example: 2A and 2B). To further delay resistance from developing, integrate other control methods into your pest management programs.

NOTES:

1. Check registration for specific site uses. Some products are labeled for sod farms and golf courses, while others are not.
2. Before purchasing and using any pesticide, read the label carefully for registered use(s), rates, and application frequency. Also note toxicity category on the label of each pesticide since toxicity ratings may affect reentry intervals and note any ventilation requirements. Wear protective clothing as recommended on each pesticide label.
3. Insecticides with a broad spectrum of activity in the chemical classes pyrethroids, organophosphates, carbamates, and neonicotinoids may be harmful to natural enemies (parasitoids and predators). Some broad-spectrum insecticides are more selective than others, and selectivity further depends on how, when, and where the insecticide is applied. Be sure to check the label for the kinds of insects controlled by the product, or contact your county extension educator for information on the use of insecticides with natural enemies.

Eric J. Rebek
Extension Entomologist