Pre-Emergent
Types of Pre-Emergent Herbicides & Their Modes of Action
Pre-emergent herbicides stop weeds before they become a problem. They work in the soil during seed germination and early seedling growth, preventing weeds from establishing while leaving desirable turf, ornamentals, or crops unharmed.
Cell Division & Root Growth Inhibitors (Dinitroanilines)
Mode of Action: These products interfere with cell division and root growth in germinating seedlings. The weed seed may sprout, but it cannot form roots or shoots and quickly dies.
Examples:
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Barricade (Prodiamine): Long-lasting control of annual grasses and broadleaf weeds in turf and ornamentals.
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Pendulum AquaCap (Pendimethalin): Controls both grassy and broadleaf weeds in lawns, landscapes, and ornamentals.
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Surflan (Oryzalin): Common in nurseries and landscapes for annual grass and broadleaf weed control.
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Team / Treflan (Trifluralin): Used in crops, turf, and ornamental plantings.
Cell Wall Synthesis Inhibitors (Broadleaf Control)
Mode of Action: These herbicides prevent proper cell wall formation in broadleaf weeds during germination. They do not control grasses but are very effective on a wide range of broadleaf species.
Examples:
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Snapshot (Isoxaben + Trifluralin): Broad-spectrum pre-emergent that combines two modes of action for grasses and broadleaf weeds.
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Isoxaben (standalone products available): Targeted for broadleaf pre-emergent control in landscapes and turf.
Photosynthesis Inhibitors (Triazines)
Mode of Action: These herbicides block Photosystem II, preventing seedlings from producing energy through photosynthesis. This results in early death of broadleaf and grassy weeds.
Examples:
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Simazine (Princep): Effective on both grassy and broadleaf weeds in turf, landscapes, and non-crop areas.
Pigment & PPO Inhibitors (Bleaching / Burn-Down with Residual)
Mode of Action: These herbicides disrupt pigment production or cell membranes, leading to bleaching or burn-down of germinating seedlings. Some products provide residual pre-emergent control.
Examples:
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Ronstar (Oxadiazon): Provides excellent control of grassy and broadleaf weeds in turf and landscapes.
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Flumioxazin (various trade names): Common in ornamental and non-crop areas for pre-emergent broadleaf control.
Key Takeaway
Pre-emergent herbicides are most effective when applied before weed seeds germinate and watered into the soil. Choosing the right product and timing your application are critical for season-long control. Always read and follow the label for safe, effective use.
At BES-TEX Supply, we are your go-to source for all herbicide solutions. Whether you’re managing lawns, landscapes, pastures, or rangeland, we carry trusted products to keep weeds under control.
4512 Adobe Dr., San Angelo, TX 76903
325.653.1300
www.BES-TEX.com