Glyphosate is the most widely used plant protection product in the world with the effective production capacity of glyphosate in China stable at about 800,000 tons/year, and the output volume maintained at 450,000 to 560,000 tons per year.
In recent years, the export volume of glyphosate has been 400,000 to 500,000 tons per year, which shows the huge demand in the international market. However, the low utilization rate leads to increased glyphosate-resistance, which seriously affects its efficacy and sustainable application. At the same time, we have a common understanding that water quality and weed grass relationship are all important factors affecting the efficacy of glyphosate, but there is a lack of research data to support these factors in application technology at present.
This article introduces why the FirstWinner tank-mix adjuvant can decrease the application rate of glyphosate and delay resistance from three aspects: Water hardness conditioning, dispersibility, and wettability.
What is FirstWinner?
FirstWinner is a kind of high-efficiency agricultural tank-mix adjuvant, which has both modification and activation functions. It can adjust the pH value and ion state of the tank-mixed solution, reduce the antagonistic effect of calcium and magnesium ions in agricultural hard water on glyphosate and other non-selective herbicides, and effectively reduce alkali hydrolysis. It improves the dispersibility and solubility of pesticides, as well as the retention, spreading and absorption capabilities, thereby contributing to glyphosate bioactivity.
1.Water hardness conditioning: FirstWinner softens the water hardness into a buffer solution which is beneficial to releasing of glyphosate AI (active ingredients) and reduces the antagonistic effect of calcium and magnesium ions in hard water, and ensures the effect of glyphosate AI.
In the process of applying glyphosate, water hardness conditioning has been ignored. Glyphosate is an organic acid, which is crystalline, has strong polarity and low solubility in water. Glyphosate acid has herbicidal activity. Therefore, glyphosate is usually made into various forms of salt or mixed salt (for example, Dimethylamine salt + potassium salt + isopropylamine salt) to improve the solubility in water (Table 1).
Table 1: Solubility of various salts
In China, the river water and groundwater used for farmland are almost alkaline, containing calcium, magnesium, iron and aluminum ions, with high content calcium and magnesium ions. When glyphosate salt is dissolved in agricultural water, various charged ions are formed. Generally, glyphosate has two negative charges, and the high concentration of calcium and magnesium ions in hard water easily react with the divalent negative ions of glyphosate to form water-insoluble salts, which easily form crystals on plant leaves and lock glyphosate, thus affecting the efficacy of glyphosate (as shown in Figure 1).
According to OASIS’ calculations, generally in the case of high hard water (450-700ppm/L), there will be 6.75-10.5g of precipitation in 15L glyphosate solution. FirstWinner can combine the calcium and magnesium ions in the water to form a stable chain structure and become an absorbable state, which makes glyphosate anion lose the opportunity to react with calcium and magnesium and improve the solubility of glyphosate (Figure 2). Therefore, the FirstWinner must be added before glyphosate.
Fig. 1: A metal ion (M2+), such as calcium and magnesium, is combined with two negative charges on glyphosate molecule (Source: Courtesy of the University of Nebraska-Lincoln)
Fig. 2: First Winner combines with calcium and magnesium ions to form a stable chain structure
OASIS conducted a greenhouse study to determine the ED50 and efficacy loss of glyphosate isopropylamine salt 480 SL (hereafter abbreviated as IPA) on Lambsquarters (Chenopodium album L.) under different hardness and with or without FirstWinner. Lambsquarters (Chenopodium album L.) was selected as the target weed because its leaves were particularly hydrophobic. In 300ppm hard water, after adding Firstwinner, ED50 was 15g ai/ha, while without adding FirstWinner, it was 261g ai/ha, which saved 246g ai/ha of glyphosate AI, and the efficacy loss decreased from 76% to 2%. In 500ppm hard water, the ED50 was 21g ai/ha after adding FirstWinner, while it was 301g ai/ha without adding FirstWinner, which saved 280g ai/ha of glyphosate AI and reduced the efficacy loss from 80% to 5% (Table 2). It can be seen that FirstWinner greatly reduced the antagonistic effect of metal ions in water on glyphosate and improved the application rate of glyphosate.
Table 2: Comparison of ED50 and efficacy loss of IPA on Chenopodium glaucum under different hardness and with or without FirstWinner
Water hardness (ppm)
Dilute 1000 times
69 g ai/ha
15 g ai/ha
2.Matched dispersibility: Ensures atomization effect, fully deposits and covers the target weeds with pesticides, ensures sufficient dosage and improves the quick-acting effect of glyphosate;
The better the atomization effect, the higher the coverage rate? No, this cognition is completely wrong, because droplets size within 200μm will have the potential of spray drifting, and droplets size within 50μm will evaporate instead of falling. People cannot see the droplets that do not fall on the leaves with the naked eye. The dynamic surface tension of the silicone solution is 27Dynes/Cm, which will shear the droplets very fine so that the number of droplets size less than 200μm and less than 50μm increases, which increases the potential of pesticides drifting and reduces the effective amounts of pesticides falling on the target weeds. FirstWinner effectively ensures the dispersion degree, and the droplets are within 200-300μm, which make most of the pesticides fall on the leaves（Table 3）.
OASIS conducted a test to compare the dispersibility of IPA 150 times and FirstWinner 1500 times + IPA 150 times on two cucumber leaves respectively. After the leaves were dry, it was found that glyphosate precipitated from leaves without FirstWinner (Figure 4).
Table 3: Comparison of dynamic surface tension, wetting time and dry time of different adjuvant aqueous solutions
Adjuvant aqueous solution
Dynamic surface tension （Dynes/Cm）
Draves Wetting (Seconds)
Water+Methylated Vegetable Oil
Fig. 3: The effect of FirstWinner on the wetting and absorption of IPA in leaves
3.Enhancing wettability, adhesion, spreadability and penetration on leaves with thick waxy layer. make them reach the action site quickly, thus improving the quick-acting effect of glyphosate.
The wetting time of FirstWinner aqueous solution is longer than that of silicone, but the drying time is more than 120 seconds, far exceeding that of silicone (10 seconds). Therefore, FirstWinner can prolong the drying time of pesticides and provide sufficient action time for glyphosate (Table 3);
FirstWinner can improve the wettability of pesticides, and make the pesticides fully adhere to the leaves to ensure that the pesticides are fully absorbed and resist rain erosion (Figure 4).
Remarks: After spraying, it rained 50 minutes later, Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences
Fig. 4: FirstWinner improves wettability and rain erosion resistance of pesticides
OASIS and Northeast Agricultural University jointly carried out the experiment of reducing glyphosate application rate and increasing the efficiency by FirstWinner application effect of FirstWinner 1500 times + glyphosate isopropylamine 480SL 150 times is better than that of glyphosate isopropylamine 480SL 100 times. The recommended scheme is FirstWinner1000-1500 times+ glyphosate isopropylamine 150 times (Figure 5).
It can be observed that there are still green weeds in the areas treated by glyphosate 100 times and 150 times, which indicates that the roots of weeds have not been killed, and the weeds are still undergoing photosynthesis. In rain and strong winds, the weeds will recur in large areas.
FirstWinner's three major functions:
A . Water hardness conditioning,
From protecting the amount of glyphosate's active ingredients to fully adhering to the target weeds. It systematically solves the problem of contact between glyphosate and the target, modifies and activates the function of glyphosate acid, improves the quick-acting and lasting effect of glyphosate, reduces the dosage of glyphosate, thus further reducing the cost of use.
Fig. 5: Field trial of FirstWinner on reducing glyphosate and increasing efficiency (14 days after treatment)
For more information about FirstWinner, please follow the company website or contact us directly.
OASIS website: www.oasisagro.com