Bromoxynil is a broad-spectrum herbicide used to control annual and perennial broadleaf weeds in a variety of crops, including cereals, cotton, rice, sorghum, and soybeans. It is also effective on certain grasses such as barnyard grass, bermudagrass, and Johnson grass. Bromoxynil is most commonly used in post-emergent applications.
A potent herbicide, bromoxynil has been widely used in agriculture to control a wide range of weeds, making it an essential tool in modern farming practices. Bromoxynil is available in various dosage forms, including liquid, granules, and wettable powder. It can be applied using ground or air equipment.
In this blog, we’ll explore what bromoxynil is, how it works, its benefits, and best practices for using it in your farming operation.
How does bromoxynil work?
Bromoxynil works by inhibiting the enzyme photosystem II, which is essential for the light-dependent reactions of photosynthesis. Photosystem II is responsible for capturing light energy and using it to produce chemical energy that drives metabolic processes in plants. Bromoxynil specifically binds the D1 protein subunit of photosystem II, which is required for electron transfer during light-dependent reactions.
By inhibiting photosystem II, bromoxynil disrupts the ability of plants to generate energy through photosynthesis. This causes the energy reserves in the weed to be depleted rapidly, leading to its death. Importantly, bromoxynil is selective in its activity, meaning it primarily affects broadleaf weeds and has little effect on grasses and other non-target crops.
Bromoxynil is often used as a post-emergence herbicide, which means it’s sprayed directly onto the foliage after the weed has grown out of the soil. It is absorbed by the leaves and transferred throughout the plant, effectively controlling a wide range of broadleaf weeds in a variety of crops.
Benefits of using bromoxynil
Bromoxynil is a widely used herbicide with several advantages in agricultural and horticultural applications:
Effective Control of Broadleaf Weeds: Bromoxynil is very effective in controlling a wide variety of broadleaf weeds, including many thorny weeds such as quinoa, clover, and ragweed.
Selective Activity: One of the main advantages of bromoxynil is its selective activity, meaning it primarily affects broadleaf weeds and has little effect on grasses and other non-target crops. This allows effective weed control without harming the desired crop, reducing the risk of crop damage and increasing crop safety.
Post-emergence application: Bromoxynil is often used as a post-emergence herbicide, meaning it is applied after the weeds have emerged from the soil. This provides flexibility in timing and allows targeted application of actively growing weeds, resulting in effective control and reducing the need for pre-emergence applications.
Short residual activity: Bromoxynil has a relatively short residual activity in the soil, which means it does not persist in the environment for long periods of time. This allows flexibility in crop rotation and minimizes the risk of herbicide residues to subsequent crops.
Tank mix compatibility: Bromoxynil is often used in tank mix combinations with other herbicides to provide a synergistic or additive effect for enhanced weed control. This allows for greater flexibility in herbicide programs and helps manage weed resistance.
Broad crop tolerance: Bromoxynil has broad crop tolerance, making it compatible with many important crops such as cereals, corn, and cotton. It can be used in a variety of cropping systems and is an important tool in an integrated weed management program.
Some bromoxynil products to consider
There are so many bromoxynil products (Bromoxynil and its esters) on the market that it can be difficult to know which one to choose.
Here are three bromoxynil products we recommend:
| Name | Bromoxynil (phenol) | Bromoxynil octanoate | Bromoxynil heptanoate |
| CAS No | 1689-84-5 | 1689-99-2 | 56634-95-8 |
| Structural formula |  |
 |
 |
| Solubility in water | 539 mg/l at pH5; 90 mg/l in distilled water; > 3100 mg/l at pH9 |
0.17 mg/l at pH5; 0.08 mg/l at pH7; 0.15 mg/l at pH9 |
0.04 mg/l at pH5. 0.03 mg/l at pH7 and pH9 |
| Solubility in solvents | Acetone = 170 g/l Methanol = 90 Tetrahydrofuran = 410 Petroleum oils < 20 |
Acetone = 1215 g/l Methanol = 207 ethyl acetate = 847 octanol = 196 toluene = 813 heptane = 368 |
Acetone = 1113 g/l Methanol = 553 ethyl acetate = 811 octanol = 270 toluene = 838 heptane = 562 dichloromethane = 851 |
Bromoxynil octanoate and bromoxynil heptanoate are the esters of bromoxynil phenol, which have better solubility in organic solvents, which can improve the stability of emulsifiable concentrate products and the capability of anti-freezing.
With their physical and chemical properties, bromoxynil octanoate and bromoxynil heptanoate could be widely used worldwide. But due to some marketing reasons, bromoxynil heptanoate is only used in North America at present.
In most products, the BROMOXYNIL is present as an ester. The representative formulated product is “Bromoxynil-octanoate EC 327.5 g/L EC”, an emulsifiable concentrate (EC) containing 327.5 g/L bromoxynil octanoate (equivalent to 225 g/L pure bromoxynil).
How to use bromoxynil?
Bromoxynil should always be used in accordance with specific product label instructions as well as local regulations and best management practices.
Here are some general guidelines on how to use bromoxynil:
Read and follow labels: Carefully read and follow label directions for the bromoxynil herbicide product you are using.
Choose the right product and rate: Choose the right bromoxynil product and rate based on the target weed, crop, growth stage, and environmental conditions.
Timing of application: Bromoxynil is often used as a post-emergent herbicide, so it should be applied after the weeds are present and actively growing.
Method of Application: Bromoxynil is usually applied as a foliar spray, usually in the form of a water-based solution. Use proper application equipment, such as calibrated sprayers, to ensure even coverage of target weeds while minimizing drift and off-target effects.
Crop Safety: Bromoxynil is selective for broadleaf weeds and is generally safe on many crops, although some crops may be sensitive to bromoxynil.
Safety Precautions: Take appropriate safety precautions when handling, mixing, and administering bromoxynil. Wear appropriate personal protective equipment (PPE) such as gloves, gowns, and goggles as directed on the label.
Practical application of Bromoxynil to crops
Bromoxynil is a herbicide commonly used in post-emergent applications to control broadleaf weeds in various crops.
The following are practical application guidelines for the use of bromoxynil on different crops:
Wheat: Bromoxynil can be applied to wheat as a post-emergence herbicide, usually when the wheat is at the 2-4 leaf stage and the target weeds are vigorously growing. It is effective against broadleaf weeds such as mustard greens, cleavers, and geraniums. Recommended application rates are usually between 0.3 and 0.4 kg/ha, but it is important to follow label directions for specific application rates and when.
Oats: Bromoxynil can be used in oats as a post-emergence herbicide to control broadleaf weeds, including species such as wild buckwheat, quinoa and quinoa. Application times and rates are similar to wheat, generally between 0.3 and 0.4 kg/ha, but it is important to refer to the label for exact instructions.
Corn: Bromoxynil is used in corn as a post-emergence herbicide for the control of broadleaf weeds such as ragweed, quartered, and velvet. The timing of the application is critical. It is recommended to apply bromoxynil at the 2-6 leaf stage of corn and the cotyledon-4 leaf stage of weeds. Typical application rates for maize are about 0.3 to 0.4 kg/ha, but see the label for specific instructions.
Soybean: Bromoxynil can be used as a post-emergent herbicide in soybeans to control broadleaf weeds. The best application time is soybean 1-3 three-leaf stage, weed cotyledon to 4-leaf stage. Recommended application rates are usually around 0.3 to 0.4 kg/ha, but always follow label directions for the exact amount and time to apply.
Other Crops: Bromoxynil can also be used on other crops such as peas, lentils, flax, and other broadleaf crops for post-emergence weed control. Application timing, rate, and method may vary with crop type, weed species, and local growing conditions. Always refer to the label for specific instructions.
Conclusion
Bromoxynil, with its unique mode of action, broad-spectrum control, and compatibility with a variety of crops, makes it a valuable tool for weed control in agriculture.
Additionally, bromoxynil is a solid choice for sustainable weed management practices, helping farmers reduce their reliance on harmful herbicides and minimize their environmental impact. To learn more information about our herbicides, please feel free to contact us at info@hb-p.com.
