Understanding the Harmony Extra Herbicide Formula
Harmony Extra is a well-known agricultural product designed for the post-emergence control of broadleaf weeds in cereal crops, such as wheat, barley, and triticale. Formerly a DuPont product, it is now manufactured by FMC Corporation and features TotalSol soluble granule technology for better dissolution and application. The efficacy of this herbicide lies in its precise combination of active and inactive components, with the active ingredients targeting the weeds' growth processes at a cellular level.
The Primary Active Ingredients
The core of Harmony Extra's weed-killing power comes from two sulfonylurea compounds: Thifensulfuron-methyl and Tribenuron-methyl. These active ingredients are responsible for the herbicide's selective action against broadleaf weeds while remaining safe for most target crops.
- Thifensulfuron-methyl: Comprising 33.33% of the formula, this compound is a systemic herbicide absorbed by the foliage and roots of weeds. It inhibits the ALS enzyme, stopping the production of essential amino acids needed for plant growth. This disruption halts cell division, leading to growth cessation and eventual weed death.
- Tribenuron-methyl: This compound makes up 16.67% of the active formula and works similarly to Thifensulfuron-methyl. It is also a selective, systemic, post-emergence sulfonylurea herbicide that inhibits the ALS enzyme. It inhibits cell division in the plant's meristematic regions. This dual-action approach helps ensure broader weed control and can aid in managing resistance.
Inactive Ingredients and Formulation Features
While the active ingredients do the heavy lifting, the inactive ingredients and the formulation itself play crucial roles. Harmony Extra SG features TotalSol® soluble granules, which ensure complete dissolution in water. This leads to better coverage and easier sprayer clean-out.
According to a 2018 Safety Data Sheet, inactive components include:
- Trisodium phosphate dodecahydrate (1-5%)
- Sodium carbonate (10-15%)
- Other proprietary ingredients (30-39%)
Mode of Action: The ALS Inhibition Pathway
The mechanism of action for both active compounds is the inhibition of the Acetolactate Synthase (ALS) enzyme, which is vital for the synthesis of key amino acids plants need to grow. Cereal crops can metabolize the active ingredients into inactive compounds, ensuring the herbicide targets weeds without harming the crop. Visible signs of weed death, such as yellowing and necrosis, typically appear within days or weeks of application.
Comparison of Harmony Extra's Active Ingredients
| Feature | Thifensulfuron-methyl | Tribenuron-methyl |
|---|---|---|
| Concentration | 33.33% | 16.67% |
| Mode of Action | Inhibits the ALS enzyme, blocking amino acid synthesis. | Inhibits the ALS enzyme, blocking amino acid synthesis. |
| Absorption | Primarily absorbed by foliage, with some root uptake. | Absorbed by both leaves and roots. |
| Selectivity | Selective for cereal crops, which metabolize the chemical into inactive substances. | Selective for cereal crops, which metabolize the chemical quickly. |
| Control Speed | Inhibits growth rapidly, with visible effects appearing within 1-3 weeks. | Inhibits growth rapidly, with visible effects typically appearing within 5-10 days. |
Application, Safety, and Environmental Considerations
Correct application of Harmony Extra is crucial for effectiveness and minimizing risks. Apply to young, actively growing weeds for best results. Applications can be via ground or air, following mixing instructions and using spray adjuvants carefully. Tank-mixing with other herbicides can expand the weed control spectrum, ensuring compatibility.
Safety is paramount; the product label and Safety Data Sheets (SDS) detail precautions, including wearing personal protective equipment (PPE). Instructions for washing and rinsing after contact are provided. Proper disposal of wastes prevents water source contamination.
Environmentally, sulfonylurea herbicides can persist in the soil, especially in alkaline conditions. Repeated use of ALS-inhibitors can lead to herbicide-resistant weed biotypes, making resistance management, like rotating herbicide modes of action, essential.
Conclusion: Maximizing Weed Control with Harmony Extra
In conclusion, the active ingredients in Harmony Extra are Thifensulfuron-methyl (33.33%) and Tribenuron-methyl (16.67%), systemic sulfonylurea herbicides that inhibit the ALS enzyme in broadleaf weeds. This dual action and the TotalSol soluble granule formulation provide effective, selective, post-emergence weed control in cereal crops. Adhere to safety guidelines and resistance management best practices for long-term efficacy and safety. Refer to the official product label for detailed usage and safety information.
US EPA, Pesticide Product Label, HARMONY EXTRA SG HERBICIDE ...
