Agrisel Sulfentrazone 4F is a concentrated suspension herbicide designed for pre-emergence and residual control of tough broadleaf weeds, grasses, and sedges in crops like soybeans, turfgrass, and field corn. By inhibiting the protoporphyrinogen oxidase (PPO) enzyme in susceptible plants, it halts chlorophyll production and causes rapid cell membrane breakdown. Farmers and turf managers use it to suppress troublesome species such as yellow nutsedge, pigweed, and nightshade before they establish root systems.
Choosing the right application rate requires analyzing soil texture and organic matter levels. Coarse soils with low organic matter demand lower rates to prevent crop injury, while fine-textured soils with higher organic matter need higher doses for effective residual control. Always calibrate spray equipment carefully and maintain uniform boom pressure to avoid overlapping passes that concentrate active ingredients.
Mechanism of Action and Weed Spectrum
Sulfentrazone belongs to the aryl triazolinone chemical family, classified as a Group 14 herbicide. When applied to the soil surface, it creates a chemical barrier. Emerging weed shoots and roots absorb the active ingredient during germination, leading to rapid necrosis under sunlight.
Its primary targets include hard-to-control weeds that resist traditional glyphosate applications:
- Sedges: Yellow nutsedge, purple nutsedge, and annual sedge species.
- Broadleaf Weeds: Common lambsquarters, waterhemp, Palmer amaranth, morningglory, and pigweed.
- Grasses: Large crabgrass, barnyardgrass, and goosegrass (partial pre-emergence suppression).
Tank-mixing Sulfentrazone 4F with complementary herbicides broadens the weed spectrum. For instance, pairing it with glyphosate for burn-down applications knocks down existing emerged vegetation while sulfentrazone handles incoming flushes. According to the National Pesticide Information Center, understanding active ingredient chemistry helps applicators protect non-target organisms and prevent runoff.
Application Guidelines and Timing
Timing dictates success when working with residual herbicides. Pre-emergence applications should occur before crop emergence, typically immediately after planting or up to three days post-planting, provided the crop seed has sufficient soil coverage to avoid direct chemical contact.
- Soil Preparation: Ensure seedbeds are firm and free of large clods so the herbicide forms an even, uninterrupted surface layer.
- Carrier Volume: Apply in a minimum of 10 to 40 gallons of water per acre using flat-fan nozzles that minimize drift.
- Incorporation: Shallow incorporation or rainfall (0.5 to 1 inch) shortly after application activates the chemical barrier in the top soil profile.
Post-emergence directed sprays require extreme caution. If crops have already emerged, shields must prevent spray contact with green crop tissue to avoid severe leaf burn and stunting. For official regulatory guidelines and safety data sheets, consult the CDMS Label Database.
Common Application Mistakes to Avoid
Even experienced applicators make avoidable errors that reduce weed control efficacy or cause crop damage. Recognizing these pitfalls saves time and protects investment returns.
- Overlapping Spray Passes: Double-spraying headlands or turns doubles the active ingredient concentration, frequently causing crop stunting or stand loss.
- Ignoring Soil Characteristics: Applying high rates on sandy, low organic matter soils increases the risk of herbicide leaching into the root zone during heavy rains.
- Improper Nozzle Selection: Using coarse droplets can lead to poor coverage on rough soil surfaces, while fine droplets increase off-target drift risks.
- Delayed Activation: Failing to receive adequate rainfall or mechanical incorporation within two weeks of application diminishes residual weed control.
Frequently Asked Questions
Can Agrisel Sulfentrazone 4F be tank-mixed with liquid fertilizers?
Yes, but you must conduct a jar test first to check for physical compatibility. Mix small proportions in a glass jar before filling the main spray tank to prevent severe clumping or line blockages.
What is the typical residual activity window in soil?
Under normal moisture and temperature conditions, sulfentrazone provides residual control lasting between four to eight weeks, depending on application rates and microbial breakdown rates.
How does soil pH affect sulfentrazone activity?
Soil pH directly influences the adsorption and availability of sulfentrazone. In soils with a higher pH, the chemical is more mobile, which increases both weed control efficacy and the potential for crop injury.
What protective equipment is required during handling?
Applicators must wear long-sleeved shirts, long pants, chemical-resistant gloves made of barrier laminate or butyl rubber, protective eyewear, and socks with shoes during mixing, loading, and application.
