Pre-emergent and Post-emergent Lawn Herbicides
By Dean Mosdell, Ph.D., technical services manager for Syngenta
A weed can be defined simply as a plant growing where it’s not wanted. An agronomic view would add that weeds compete for water, light and space with desirable plants, and can harbor diseases and insects. But to a homeowner, and your customer, weeds diminish the aesthetic value of their lawn and landscape plantings.
Importance of preemergent control
A weed control plan for lawn and landscapes should include a preemergent program that includes a product such as Barricade® brand herbicide to prevent development of weed seedlings. This is particularly important for grass weed control as there are few options for post-emergent grass control. Depending on turf type, Tenacity® and Manuscript® herbicides have pre- and/or post- emergent activity on certain grass weeds, such as crabgrass, on turf. However, in landscape beds, woody and herbaceous plants can be sensitive to post- emergent herbicide applications.
The most common post-emergent weed control practice in landscape beds (and edging) is applying a non-selective herbicide as a direct spray to prevent contact with desirable plants. As Lawn Care Operators (LCOs) evaluate herbicides for edging and control of weeds, Reward® herbicide offers fast burn down of grass and dicot weeds without concern of staining concrete, volatility and movement from the application site.
Reward is a contact, non-selective herbicide that disrupts photosynthesis, causing degradation of cell walls. Desiccation of green plants tissue can be seen within hours of application, burning all the foliage it contacts. Reward can be applied as a broadcast spray or in a backpack sprayer for spot treatment applications at 0.75 oz. per gal. All applications will need a non-ionic surfactant to enhance plant surface coverage. Other lawn uses include:
- Weed control in joints and edges of hard surfaces around the landscape
- Winter weed control such as Poa annua in dormant turf
- Burn down of existing bermudagrass turf prior to overseeding with ryegrass for winter color
Fusilade® II Turf and Ornamental herbicide is a selective, systemic herbicide that inhibits the fatty acid synthesis that is required for the growth of new weeds. Because of this mode of action, grass weed control may take two to three weeks, although the plant will stop growing within a week after application. Fusilade II is grass herbicide and is safe to use around ornamental plants and on fine fescue turf. The spot treatment rate for Fusilade II in landscape beds, fence lines and non-turf areas is 0.75 oz. per gal. Poa annua and fine fescue are naturally tolerant to Fusilade II.
If perennial grass weeds are a component of the weed population that you want to control in landscape beds and other non-turf areas, Fusilade II and Reward can be tank-mixed together at 0.75 oz per gal. of each herbicide plus a non-ionic surfactant. This mixture will enhance control of perennial grass weeds such as bermudagrass, bentgrass, quackgrass, etc.
Selecting a herbicide
|Product||Trim and Edge||Landscape Beds||Renovation||Dormant Turf||Non-Crop IVM|
Always consult the product label for complete use and application information
|Reward||Pros: quick burndown of all vegetation (visual effects within 24- 36 hours); short reseeding interval; aquatic weed control|
Note: regrowth of perennial plants; limited tank mix partners
|Fusilade II||Pros: control of grasses such as bermudagrass; safe around ornamental dicot plants|
Note: no Poa annua activity; reseeding > 14 days; slow acting; limited tank mix partners
For additional herbicide offerings, please visit GreenCastOnline.com or contact your local Syngenta Territory Manager.
*Will not kill perennial plants
© 2021 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties and/or may have state-specific use requirements. Please check with your local extension service to ensure registration and proper use. Barricade®, Fusilade®, GreenCast®, Manuscript®, Reward®, Tenacity® and the Syngenta logo are trademarks of a Syngenta Group Company. All other trademarks used herein are the property of their respective owners.