General Information


Meridian 25WG is a broad-spectrum insecticide that is effective when applied at label rates to turfgrass, plant foliage and soil.

Meridian 25WG is active against many sucking and chewing insect pests by contact and ingestion. Meridian 25WG is relatively short-lived on the surface of plant foliage, readily absorbed into plant tissues, and rainfast once it has dried. The rapid translaminar absorption and distribution within leaves provides excellent residual control of foliar feeding insects.

In the soil, the active ingredient in Meridian 25WG will control soil pests upon contact or ingestion and is also readily taken up by plant roots. The active ingredient moves upwards in the plant to the site of pest infestation.

Through feeding on the plant, pests are exposed to the active ingredient in Meridian 25WG. Feeding will stop within minutes to hours of exposure and be followed by death of the pest. The moderate persistence of Meridian 25WG in the soil and foliage also provides residual control of labeled pests. Meridian 25WG is not active as an ovicide or as an insect growth regulator. Because residues on leaf surfaces are quickly degraded, Meridian 25WG is compatible with beneficial arthropods.


Meridian 25WG belongs to the neonicotinoid class of chemistry (Group 4A Insecticide). Pests which are resistant to insecticides in other chemical classes are not known to be cross-resistant to Meridian 25WG. However, insect pests are known to develop resistance to products used repeatedly.

Because resistance development cannot be predicted, the use of Meridian 25WG should conform to sound resistance management strategies established for the crop and use area. Strategies should include rotation of chemicals with different modes of action, limitation of the number of successive generations of the target pest being treated with the same compound and adherence to labeled directions.

Consult your local pest control advisor or extension office for additional methods for preventing resistance development. SYNGENTA encourages responsible product stewardship to ensure effective long-term control of the insect pests on the label.

Limitations, Restrictions, and Exceptions


Sites of Application

Meridian 25WG can be applied to turfgrass on: golf courses, residential lawns, commercial grounds (i.e., office and shopping complexes, airports), parks, playgrounds, athletic fields and sod farms.


- DO NOT apply this product through any type of irrigation system.

- DO NOT apply more than 17.0 ounces of Meridian 25WG (0.266 pounds thiamethoxam) per acre per year

Broadcast Applications to Turfgrass

Apply Meridian 25WG as a broadcast application to turfgrass for control of targeted pests. Use sufficient water volume (1.5 - 5 gal./ 1000 square feet) to uniformly distribute Meridian 25WG over the area being treated and to adequately move the active ingredient into the canopy and thatch layers. To help prevent grubs, irrigate within seven (7) days of application to move Meridian 25WG into the root zone where grubs feed. To control grubs, irrigate within one (1) day of application to move Meridian 25WG into the root zone where grubs feed. Maintain adequate soil moisture before and after application for optimum control and healthy turfgrass growth. Excessively wet or dry conditions may impact the performance of Meridian 25WG against white grubs and mole crickets. Do not mow turf until the treated area has been irrigated or rainfall has occurred to allow for maximum and uniform uptake into turfgrass.Application Timing

For Larvae (white grubs): Meridian 25WG is effective at labeled rates when applied as a preventative or curative treatment.

- As a preventative treatment, Meridian 25WG may be applied up to 45 days before the historical peak of adult flight for the targeted species.

- As a curative grub treatment, make the application from egg hatch to second instar (grubs less than half their full size).

- For optimum white grub control, apply Meridian 25WG from peak adult flight through peak egg hatch of the primary species being targeted.

For suppression of mole crickets: apply Meridian 25WG preventatively from first to peak egg hatch of the generation being targeted.

For suppression of Chinch bugs: apply Meridian 25WG when young nymphs are first observed.


Application Timing:

Apply up to 45 days before the historical peak of adult flight to 2nd instar grub of the species being targeted.

For optimum control, treat from peak flight to peak egg hatch.

To control grubs, make the application from egg hatch to second instar (grubs less than half their full size).

For specific information about developmental stages of the target pest and optimal timing of applications, consult with your State Cooperative Extension Service.

Note: For turf with heavy thatch (more than 0.75 inches), use the higher rates within the recommended range. Meridian 25WG is not phytotoxic to any major turfgrass species.

Note: Meridian 25WG provides suppression of mole crickets and chinch bug populations on turfgrass. Suppression can mean either erratic control, ranging from good to poor, or a consistent level of control below that generally acceptable for commercial purposes.

Restricted Entry Interval

12 hours