A cotton defoliation ripening composition and use thereof

Abstract

The present application belongs to the technical field of plant pesticides, and particularly relates to a cotton defoliation and ripening composition and application thereof. The cotton defoliation and ripening composition comprises gibberellic acid and thiabendazole; wherein the mass ratio of the gibberellic acid to the thiabendazole is 1:5-120. The cotton defoliation and ripening composition provided by the present application not only significantly improves the defoliation rate through the synergistic effect of the gibberellic acid and the thiabendazole, but also effectively reduces the phenomenon of 'burning and withering branches' by promoting the natural formation of abscission layer, thereby reducing the impurities of machine-picked cotton from the source. The cotton defoliation and ripening composition provided by the present application promotes the concentrated boll shedding while realizing efficient defoliation.

Description

Technical Field

[0001] This invention belongs to the field of plant pesticide technology, specifically relating to a cotton defoliation and ripening composition and its application. Background Technology

[0002] cotton( Gossypium hirsutum As a major economic fiber crop in my country, the efficiency of mechanized harvesting and the final fiber quality of cotton largely depend on the effectiveness of defoliation before harvesting. In intensive production areas, chemical defoliation has become a key agronomic step in achieving standardized mechanized cotton harvesting. Efficient defoliation aims to induce rapid and uniform leaf shedding, simultaneously promoting concentrated boll opening, thereby significantly reducing the impurity content of machine-harvested seed cotton, improving the harvesting rate, and ensuring fiber quality.

[0003] Currently, thiamethoxam, a plant growth regulator based on cytokinins, is the most widely used defoliant. Its mechanism of action involves inducing ethylene biosynthesis, promoting the formation and degradation of the abscission layer at the base of the petiole, thereby achieving physiological leaf shedding and avoiding the problem of leaves "withering but not falling off." However, the defoliation effect of thiamethoxam alone exhibits significant environmental dependence; its efficacy is easily affected by external conditions such as temperature, light, water, and the physiological state of the cotton plant. Single application often leads to incomplete defoliation or inhibited abscission layer formation. Furthermore, this agent has a relatively limited catalytic effect on cotton boll opening.

[0004] To compensate for the aforementioned shortcomings, existing technologies commonly employ a combination of thiabendazole and the photosynthesis-inhibiting herbicide diuron, such as the popular 540 g / L thiabendazole·diuron suspension. While this combination can accelerate abscission layer formation and increase defoliation rate to some extent, it introduces serious environmental and safety issues. Diuron has high ecotoxicity, and its residues and drift in the environment pose potential risks to non-target organisms and ecosystems, failing to meet the requirements of green and sustainable agricultural development. The strategy of combining the mainstream defoliant thiabendazole with the photosynthesis-inhibiting herbicide diuron carries environmental pollution risks. Summary of the Invention

[0005] To address the environmental pollution risks associated with existing techniques that combine the mainstream defoliant thiabendazole with the photosynthesis inhibitor herbicide diuron, this invention aims to provide a novel defoliation technology that is highly efficient, environmentally friendly, and stable. By introducing gibberellic acid and thiabendazole for synergistic effects, the aforementioned drawbacks are effectively overcome. This significantly improves the defoliation rate while reducing the use of highly toxic pesticides, lowering environmental pollution risks, promoting concentrated boll opening in cotton, and improving cotton quality. To achieve the above objectives, this invention adopts the following technical solution:

[0006] The present invention provides a cotton defoliation and ripening composition comprising gibberellic acid and thidiazuron.

[0007] The mass ratio of gibberellic acid to thiabendazole is 1:5~120.

[0008] This invention replaces diuron in mainstream formulations with the plant growth regulator gibberellic acid, fundamentally avoiding the risk of environmental pollution. Specifically, diuron, as a photosynthesis inhibitor herbicide, works by blocking the electron transport chain in plants, exhibits broad-spectrum toxicity to non-target organisms, and has a long half-life in soil lasting several months, easily leading to soil residues and water pollution. In contrast, gibberellin, the main component of gibberellic acid, is a natural growth hormone present in plants. It can be rapidly degraded into harmless substances by microorganisms in the environment, with a half-life of only a few days, making it ecosystem-friendly. Meanwhile, this invention achieves a synergistic effect between gibberellic acid and thiamethoxam through a specific ratio of 1:5 to 120. Gibberellic acid can significantly enhance and stabilize the defoliation effect of thiamethoxam. The combination of the two provides an alternative solution that does not rely on diuron while achieving the same or better defoliation and ripening effect. This achieves the dual goals of efficient defoliation and environmental protection, and can solve the problem of environmental pollution risks associated with the existing strategy of combining the mainstream defoliant thiamethoxam with the photosynthesis inhibitor herbicide diuron.

[0009] Preferably, the formulation of the cotton defoliation and ripening composition is a wettable powder, a water-dispersible granule, or a suspension.

[0010] Preferably, the cotton defoliation and ripening composition further includes pesticide-acceptable adjuvants.

[0011] Preferably, the additive is selected from any one or more of surfactants, spray additives, deposition additives, anti-drift additives, and functional additives.

[0012] The present invention also provides the application of a cotton defoliation and ripening composition in the defoliation and ripening of cotton.

[0013] Preferably, the cotton defoliation and ripening composition is applied 15 to 25 days before cotton harvest.

[0014] Preferably, the cotton defoliation and ripening composition is applied in stages or in combination.

[0015] Preferably, the step-by-step application process is as follows: First, prepare gibberellic acid into an aqueous solution and spray it. After an interval of 2 to 4 hours, prepare thiabendazole into an aqueous solution and spray it.

[0016] Preferably, the process of mixed application is as follows: After mixing gibberellic acid and thidiazuron in a mass ratio of 1:5~120 to form an aqueous solution, it is applied as a single spray.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention provides a cotton defoliation and ripening-promoting composition comprising the plant growth regulator thidiazuron (TDZ) and gibberellic acid (GA); wherein the mass ratio of gibberellic acid to thidiazuron is 1:5~120. This cotton defoliation and ripening-promoting composition exhibits stable defoliation promotion under different environmental conditions and significant economic and environmental friendliness. This invention fundamentally avoids environmental pollution risks by replacing diuron in the mainstream formulation with the plant growth regulator gibberellic acid. Specifically, diuron, as a photosynthesis inhibitor herbicide, works by blocking the plant electron transport chain, exhibits broad-spectrum toxicity to non-target organisms, and has a long half-life in soil lasting several months, easily leading to soil residues and water pollution; while gibberellin, the main component of gibberellic acid, is a natural plant growth hormone that can be rapidly degraded into harmless substances by microorganisms in the environment, with a half-life of only a few days, making it ecosystem-friendly. Meanwhile, this invention achieves a synergistic effect between gibberellic acid and thiamethoxam through a specific ratio of 1:5 to 120. Gibberellic acid can significantly enhance and stabilize the defoliation effect of thiamethoxam. The combination of the two provides an alternative solution that does not rely on diuron while achieving the same or better defoliation and ripening effect. This achieves the dual goals of efficient defoliation and environmental protection, and can solve the problem of environmental pollution risks associated with the existing strategy of combining the mainstream defoliant thiamethoxam with the photosynthesis inhibitor herbicide diuron.

[0018] 2. This invention has significant advantages in several aspects: Regarding defoliation performance, the synergistic effect of gibberellic acid and thidiazuron not only significantly improves the defoliation rate but also effectively reduces the "scorched and hanging branches" phenomenon by promoting the natural formation of the abscission layer, thus reducing impurities in machine-harvested cotton from the source; Regarding environmental compatibility, this system completely avoids highly toxic components such as diuron, significantly reducing ecological risks, while simultaneously reducing pesticide dosage through synergistic effects; Regarding application stability, the regulatory function of gibberellic acid effectively improves the environmental adaptability of defoliation, ensuring stable defoliation under different climatic and cultivation conditions; Regarding comprehensive agronomic benefits, this solution promotes concentrated boll opening while achieving efficient defoliation; Furthermore, the flexible setup of both stepwise and mixed application modes provides adaptable solutions for different production scenarios. 3. From an industrialization perspective, gibberellic acid, a commonly used plant growth regulator in agricultural production, has a complete industrial chain in China, including multiple raw material and formulation manufacturers, ensuring stable supply. Regarding application costs, based on the technical solution recommended by this invention (gibberellic acid dosage 20 mg / L, 50% thiamethoxam dosage 30 g / mu), combined with market price calculations, the cost per mu is approximately 3.74 yuan. Compared to the currently mainstream thiamethoxam-diuron compound (cost approximately 5-6 yuan per mu), this invention reduces costs by approximately 32% while maintaining defoliation effects, and completely avoids the environmental risks of diuron, demonstrating significant economic and environmental friendliness. Attached Figure Description

[0019] Figure 1 This invention illustrates the effects of different concentrations of gibberellic acid and 100 mg / L thidiazuron on the defoliation rate of cotton.

[0020] Figure 2 The images show the defoliation effect of representative cotton plants treated with different concentrations of gibberellic acid and 100 mg / L thidiazuron in this invention; the two samples in each treatment group are parallel samples.

[0021] Figure 3 This invention illustrates the effects of different concentrations of thiamethoxam and the addition of gibberellic acid on cotton defoliation under different temperature conditions; wherein: A represents the defoliation rate of a single cotton plant; B shows the defoliation effect of representative cotton plants in different treatment groups; Multiple samples under each different treatment condition are considered parallel samples.

[0022] Figure 4 This invention illustrates the effects of different concentrations of thiamethoxam and the addition of gibberellic acid on cotton defoliation under varying light conditions; wherein: A represents the defoliation rate of a single cotton plant; B shows the defoliation effect of representative cotton plants in different treatment groups; Multiple samples under each different treatment condition are considered parallel samples.

[0023] Figure 5 This invention illustrates the effects of different concentrations of thiamethoxam and the addition of gibberellic acid on cotton defoliation under varying soil moisture conditions; wherein: A represents the defoliation rate of a single cotton plant; B shows the defoliation effect of representative cotton plants in different treatment groups; Multiple samples under each different treatment condition are considered parallel samples.

[0024] Figure 6This invention illustrates the effects of different concentrations of thiamethoxam and the addition of gibberellic acid on cotton defoliation under different nitrogen application conditions; wherein: A represents the defoliation rate of a single cotton plant; B shows the defoliation effect of representative cotton plants in different treatment groups; Multiple samples under each different treatment condition are considered parallel samples.

[0025] Figure 7 This invention illustrates the effects of different mepiquat chloride treatments, including the use of thiamethoxam and the addition of different concentrations of gibberellic acid, on cotton defoliation; wherein: A represents the defoliation rate of a single cotton plant; B shows the defoliation effect of representative cotton plants in different treatment groups; Multiple samples under each different treatment condition are considered parallel samples. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments, but this should not be construed as limiting the invention. Unless otherwise specified, the technical means used in the following embodiments are conventional means well known to those skilled in the art, and the materials, reagents, etc. used in the following embodiments are commercially available unless otherwise specified.

[0027] Example 1: Plant Experiment 1. Plant material (cotton) variety: Xinluzao 78, whose seeds were purchased from Xinjiang Jinfengyuan Seed Industry Co., Ltd.

[0028] 2. Experimental treatments: A total of five treatment groups were established, namely, a series of concentration gradients (5 mg / L, 10 mg / L and 20 mg / L) of gibberellic acid (GA) aqueous solution and a 100 mg / L thiabendazole (TDZ) aqueous solution, referred to as 5 mg / L GA+TDZ, 10 mg / L GA+TDZ and 20 mg / L GA+TDZ respectively; a single TDZ control (100 mg / L TDZ aqueous solution, hereinafter referred to as TDZ) and a commercial thiabendazole formulation control (100 mg / L thiabendazole, hereinafter referred to as thiabendazole).

[0029] 3. The experiment was conducted in April 2025 in the photoculture laboratory of China Agricultural University, using cotton pot experiments. The pots were 10 cm in diameter and 8.5 cm high, with 2 seedlings planted in each pot. After reaching the 6-leaf stage, the cotton was treated according to the methods described in the five treatment groups above. Each treatment group consisted of 4 pots with 8 cotton plants. All treatment groups received a single application of the mixed pesticide solution. Leaf drop (leaf drop rate) was continuously observed and recorded after application for each treatment group.

[0030] The defoliation rate is calculated using the following formula: Defoliation rate = (Number of cotton leaves before application - Number of cotton leaves after application) / Number of cotton leaves before application × 100%; In the above formula, the unit for defoliation rate is %.

[0031] The results of the defoliation rate are as follows Figure 1 As shown in the image, the defoliation effect of a representative cotton plant is as follows: Figure 2 As shown in the figure. Experimental results showed that treatment with 5 mg / L, 10 mg / L, and 20 mg / L GA+TDZ aqueous solutions effectively improved the defoliation rate. Compared with TDZ alone, the defoliation rate was significantly improved from 2 to 5 days after application. Among them, at 5 days after application, the defoliation rate of the 20 mg / L GA+TDZ aqueous solution treatment was 8.5% higher than that of TDZ alone, reaching 100%. Even at lower concentrations of GA+TDZ aqueous solution, such as 5 mg / L, the defoliation effect of TDZ was significantly improved. This may be because GA enhances the absorption and transport efficiency of TDZ in leaf tissue by promoting the metabolic activity of leaf cells. At the same time, GA may accelerate the expression and activity of abscission layer cell wall degrading enzymes by regulating the balance of endogenous hormones, thereby synergistically promoting the formation and separation of the abscission layer.

[0032] Experiment Example 2: Plant Experiment 1. Plant material (cotton) variety: Lu Mian 22, whose seeds were provided by Shandong Cotton Research Center of Shandong Academy of Agricultural Sciences.

[0033] 2. Experimental treatments: Three gradients of thiabendazole (TDZ) concentrations were set up, namely 100 mg / L, 250 mg / L and 500 mg / L, which were combined with no gibberellic acid (GA) and 20 mg / L gibberellic acid, respectively, to form a total of 6 core treatments.

[0034] The experiment was conducted at three temperature gradients of 18℃, 25℃ and 32℃, with a total of 18 treatment combinations.

[0035] 3. The experiment was conducted in July 2025 in the artificial climate chamber of Beijing Forestry University. Cotton pot experiments were used. The pots were 10 cm in diameter and 8.5 cm high, with 2 seedlings per pot. Treatments were initiated at the 6-leaf stage. Each treatment combination had 4 pots, totaling 8 cotton plants. The cotton seedlings were placed in the appropriate temperature environment one day before treatment. All treatment combinations (including the GA group) were then sprayed with a mixed pesticide solution. Observations were conducted for 7 days after application, and leaf drop (leaf drop rate) was recorded.

[0036] The defoliation rate is calculated using the following formula: Defoliation rate = (Number of cotton leaves before application - Number of cotton leaves after application) / Number of cotton leaves before application × 100%; In the above formula, the unit for defoliation rate is %.

[0037] The results of the defoliation rate are as follows Figure 3 As shown in A, the defoliation effect of cotton plants treated with a combination of 100 mg / L thiamethoxam (TDZ) and gibberellic acid (GA) is shown in [reference needed]. Figure 3 B in the middle.

[0038] Experimental results showed that gibberellic acid (GA) significantly enhanced the defoliation effect of thiabendazole (TDZ) under different temperature conditions, but the characteristics of its effect varied with temperature: at a low temperature of 18℃, GA mainly played an "effect enhancement" role, increasing the defoliation rate to 49.0%~69.9%; while at a high temperature of 32℃, GA exhibited an "extreme acceleration" advantage, significantly accelerating the defoliation process in combination with the high-temperature environment, achieving a defoliation rate of 96.3%-100% within 2 days after application; at a suitable temperature of 25℃, the GA treatment group also showed a significant speed advantage. This result indicates that gibberellic acid (GA) can enhance the defoliation effect of thiabendazole (TDZ) across the entire temperature range: at low temperatures, GA mainly plays an "effect enhancement" role; while at high temperatures, GA exhibits an "extreme acceleration" advantage. This discovery provides crucial scientific basis for developing precise defoliation strategies under different temperature conditions, ensuring the stability and efficiency of chemical defoliation technology under variable climatic conditions.

[0039] Experiment Example 3: Plant Experiment 1. Plant material (cotton) variety: Lu Mian 22.

[0040] 2. Experimental Treatments: Three concentration gradients of thidiazuron (TDZ) were set up: 100 mg / L, 250 mg / L, and 500 mg / L. These were combined with either no gibberellic acid (GA) or 20 mg / L gibberellic acid, forming a total of six core treatments. The experiment was conducted under low light conditions (40% light intensity, 115.891 μmol / m²). 2 / s), medium illumination (70% light intensity, 199.365μmol / m 2 / s) and high light intensity (100% light intensity, 282.839μmol / m 2 The process was carried out under three illumination gradients ( / s), with a total of 18 processing combinations.

[0041] 3. The experiment was conducted in July 2025 in the artificial climate chamber of Beijing Forestry University. Cotton pot experiments were used. The pots were 10 cm in diameter and 8.5 cm high, with 2 seedlings per pot. Seedlings were cultivated to the 6-leaf stage before treatment. Each treatment had 4 pots, totaling 8 cotton plants. The cotton seedlings were placed in appropriate light conditions one day before treatment to acclimatize. Then, all treatment groups were sprayed with a mixed pesticide solution in a single application. After application, observation continued for 7 days, and leaf drop (leaf drop rate) was recorded.

[0042] The defoliation rate is calculated using the following formula: Defoliation rate = (Number of cotton leaves before application - Number of cotton leaves after application) / Number of cotton leaves before application × 100%; In the above formula, the unit for defoliation rate is %.

[0043] The results of the defoliation rate are as follows Figure 4 As shown in A, the defoliation effect of cotton plants treated with a combination of 100 mg / L thiamethoxam (TDZ) and gibberellic acid (GA) is shown in [reference needed]. Figure 4 B in the middle.

[0044] Experimental results showed that both light conditions and the addition of gibberellic acid (GA) significantly affected the defoliation effect of TDZ. Under low light conditions, the defoliation effect of TDZ alone was significantly inhibited, with a defoliation rate of 86.0%–89.9% seven days after application. However, the addition of GA significantly increased the defoliation rate to 100%, with complete defoliation achieved as early as four days after application. Under medium light conditions, the GA-treated groups exhibited a faster defoliation speed, reaching 100% defoliation rate four days after application, while the defoliation rate of TDZ alone was 89.4%–93.3% seven days after application. Under high light conditions, although the final defoliation effects of all treatments were comparable, the GA-treated groups still showed a faster defoliation process, achieving complete defoliation as early as four days after application. These results indicate that gibberellic acid can effectively mitigate the adverse effects of low light on the defoliation effect of thiamethoxam, significantly enhancing its defoliation efficiency and speed under low light conditions, providing an effective technical approach to solving the production problem of poor defoliation in cotton under cloudy and rainy weather conditions.

[0045] Experiment Example 4: Plant Experiment 1. Plant material (cotton) variety: Lu Mian 22.

[0046] 2. Experimental Treatments: Three concentration gradients of thidiazuron (TDZ) were set up, namely 100 mg / L, 250 mg / L, and 500 mg / L, which were combined with no gibberellic acid (GA) and 20 mg / L gibberellic acid, respectively, forming a total of 6 core treatments. Three soil relative moisture content gradients of 20%, 40%, and 80% were set up in the experiment, for a total of 18 treatment combinations.

[0047] 3. The experiment was conducted in July 2025 in the artificial climate chamber of Beijing Forestry University. Cotton pot experiments were used, with 4 pots for each treatment, 2 seedlings per pot, for a total of 8 cotton plants. After reaching the 3-leaf stage, the plants were cultivated under appropriate water conditions until the 6-leaf stage, at which point leaf drop was initiated. All treatment groups underwent a single application of a mixed pesticide solution. Observations were conducted for 7 days after application, and leaf drop (leaf drop rate) was recorded.

[0048] The defoliation rate is calculated using the following formula: Defoliation rate = (Number of cotton leaves before application - Number of cotton leaves after application) / Number of cotton leaves before application × 100%; In the above formula, the unit for defoliation rate is %.

[0049] The results of the defoliation rate are as follows Figure 5 As shown in A, the defoliation effect of cotton plants treated with a combination of 100 mg / L thiamethoxam (TDZ) and gibberellic acid (GA) is shown in [reference needed]. Figure 5 B in the middle.

[0050] Experimental results showed that both moisture conditions and the addition of gibberellic acid (GA) significantly affected the defoliation effect of TDZ. Under high moisture conditions (80%), the defoliation effect of TDZ alone was significantly inhibited, with a defoliation rate of only 44.3%–81.8% five days after application, demonstrating a decrease in effect with increasing TDZ concentration. However, the addition of GA significantly increased the defoliation rate to 100%, with complete defoliation achieved within 3–4 days after application. Under moderate moisture conditions (40%), the GA-treated groups exhibited a faster defoliation rate, reaching 100% within 4 days after application, while the defoliation rate of TDZ alone was only 62.8%–98.2% seven days after application. Under 20% drought conditions, although TDZ alone ultimately achieved a higher defoliation rate, the GA-treated groups still showed a faster defoliation process, achieving complete defoliation within 3 days after application. This result demonstrates that gibberellic acid not only achieves maximum efficiency under suitable drought conditions, but more importantly, it addresses the industry pain point of poor defoliation in high humidity environments, ensuring high reliability and consistency of defoliation effects across different years and field moisture conditions. This provides a stable technical guarantee for mechanized cotton harvesting, unaffected by weather humidity.

[0051] Experiment Example 5: Plant Experiment 1. Plant material (cotton) variety: Lu Mian 22.

[0052] 2. Experimental Treatments: Three gradients of thiabendazole (TDZ) concentrations were set up, namely 100 mg / L, 250 mg / L, and 500 mg / L, which were combined with no gibberellic acid (GA) and 20 mg / L gibberellic acid, respectively, forming a total of 6 core treatments. Three nitrogen application rate gradients were set up for total nitrogen content, namely 3 mmol / L, 9 mmol / L, and 18 mmol / L (hereinafter referred to as N3, N9, and N18, respectively), for a total of 18 treatment combinations.

[0053] 3. The experiment was conducted in July 2025 in the artificial climate chamber of Beijing Forestry University. Cotton pot experiments were used, with 4 pots per treatment, 2 seedlings per pot, for a total of 8 cotton plants. After reaching the 3-leaf stage, the plants were cultured to the 6-leaf stage according to different nitrogen ratios in the nutrient solution (N3, N9, and N18) before defoliation treatment. All treatment groups were sprayed with a single, mixed solution. Observations were conducted for 7 days after application, and leaf drop (defoliation rate) was recorded.

[0054] The defoliation rate is calculated using the following formula: Defoliation rate = (Number of cotton leaves before application - Number of cotton leaves after application) / Number of cotton leaves before application × 100%; In the above formula, the unit for defoliation rate is %.

[0055] The results of the defoliation rate are as follows Figure 6 As shown in A, the defoliation effect of cotton plants treated with a combination of 100 mg / L thiamethoxam (TDZ) and gibberellic acid (GA) is shown in [reference needed]. Figure 6 B in the middle.

[0056] Experimental results showed a significant interaction between nitrogen levels and the addition of gibberellic acid (GA) on the defoliation effect of thiamethoxam (TDZ). Under low nitrogen conditions (N3), TDZ alone exhibited superior defoliation activity, with 100 mg / L TDZ achieving 100% defoliation rate 3 days after application. With the addition of GA, all treatments at different concentrations achieved complete defoliation 2 days after application, significantly accelerating the defoliation process. Under medium nitrogen conditions (N9) and high nitrogen conditions (N18), the defoliation effect of TDZ alone was significantly inhibited, exhibiting an abnormal dose-response relationship. However, with the addition of GA, all treatments achieved complete defoliation 3 days after application, effectively overcoming the adverse effects of excessive nitrogen on defoliation. This indicates that gibberellic acid can accelerate the defoliation process under low nitrogen conditions and relieve defoliation inhibition under sufficient nitrogen conditions, thus ensuring the stability of defoliation effect under different nitrogen environments. This finding reveals that gibberellic acid can effectively improve the defoliation efficiency of thiamethoxam under different nitrogen nutrient conditions, providing an innovative solution to the production problem of unstable defoliation effect in cotton under different soil fertility conditions.

[0057] Experiment Example 6: Plant Experiment 1. Plant material (cotton) variety: Xinluzao 78.

[0058] 2. Experimental Treatments: A single thiazuron (TDZ) control (100 mg / L TDZ aqueous solution) was set up, along with combinations of 100 mg / L thiazuron (TDZ) with 10 mg / L and 20 mg / L gibberellic acid (GA), forming three core treatments. These three core treatments were then combined with two dimethoprim (DPC) administration doses of 0 mg / L (no DPC) and 300 mg / L (high DPC), resulting in a total of six treatment combinations.

[0059] 3. The experiment was conducted in May 2025 in the photoculture laboratory of China Agricultural University. Cotton pot experiments were used, with 4 pots for each treatment, and 2 seedlings per pot, for a total of 8 cotton plants. After reaching the 3-leaf stage, a corresponding mepiquat chloride treatment was applied. At the 6-leaf stage, a defoliation treatment was performed. For the defoliation treatment, the pesticide solution was mixed and sprayed once for all treatment groups. Observations were conducted for 7 days after application, and leaf drop (defoliation rate) was recorded.

[0060] The defoliation rate is calculated using the following formula: Defoliation rate = (Number of cotton leaves before application - Number of cotton leaves after application) / Number of cotton leaves before application × 100%; In the above formula, the unit for defoliation rate is %.

[0061] The results of the defoliation rate are as follows Figure 7 As shown in A, the defoliation effect of the treatment on cotton plants is shown in [reference needed]. Figure 7 B in the middle.

[0062] Experimental results showed that early DPC treatment significantly inhibited the defoliation effect of thiabendazole (TDZ), while the addition of gibberellic acid (GA) effectively improved this inhibitory effect. Under the condition of DPC 300 mg / L (high DPC), on the second day after application, the defoliation rate of TDZ alone was only 2.08%, while the defoliation rates of TDZ + 10 g / ml GA and TDZ + 20 g / ml GA increased to 29.44% and 17.22% respectively; by the third day, the defoliation rates of TDZ + 10 g / ml GA and TDZ + 20 g / ml GA were 77.22% and 82.78% respectively, which were 126% and 142% higher than that of TDZ alone (34.17%). Under the condition of no DPC, the defoliation rate of TDZ + 20 g / ml GA on the third day reached 82.74%, which was 48.8% higher than that of TDZ alone (55.58%). This indicates that gibberellic acid can not only effectively alleviate defoliation obstacles caused by DPC, but also significantly accelerate the defoliation process, providing a reliable solution to the technical problem of incomplete defoliation in chemically controlled cotton fields.

[0063] Experiment Example 7: Plant Experiment 1. Plant material (cotton) variety: Jinken 1565, whose seeds were provided by the Cotton Research Institute of Xinjiang Academy of Agricultural Sciences.

[0064] 2. Experimental treatments: There were 4 treatments in total: water control (CK); 15 g / mu of thiamethoxam (TDZ) aqueous solution; 0.8 g / mu of gibberellic acid (GA) oil suspension mixed with 15 g / mu of thiamethoxam (TDZ) aqueous solution (TDZ+GA); and 10 mL / mu of 54% thiamethoxam-dimethoxam compound aqueous solution.

[0065] 3. The experiment was conducted in September 2025 in the experimental field of the Cotton Research Institute of Xinjiang Academy of Agricultural Sciences, Shihezi City, Xinjiang Uygur Autonomous Region. A randomized block design was adopted, with 3 replicates, for a total of 12 plots, each plot being 4.6m × 7m = 32.2m. 2 The weather was sunny and windless on the day of application. The first treatment was conducted on September 6th, and the second treatment on September 13th. A backpack sprayer was used to evenly spray all leaves of the cotton plants in the plot. The leaf drop rate and boll opening rate were investigated and counted after 7, 14, and 21 days.

[0066] The defoliation rate is calculated using the following formula: Defoliation rate = (Number of cotton leaves before application - Number of cotton leaves after application) / Number of cotton leaves before application × 100%; In the above formula, the unit for defoliation rate is %; The cotton boll opening rate is calculated using the following formula: Fluff opening rate = (Number of fluffy bolls opened / Total number of bolls) × 100%; In the above formula, the unit for the fluff discharge rate is %.

[0067] Five plants were selected from each plot and tagged. The number of leaves, total number of bolls, and number of open bolls in each plot were investigated before and after the application of the pesticide. The results are shown in Table 1.

[0068] Table 1. Defoliation rate and boll opening rate of cotton after different defoliation and ripening treatments in Shihezi area. Experimental results showed that GA treatment effectively improved the defoliation rate. The defoliation rate of the TDZ+GA treatment group was 23.5%, 16.6%, and 16.1% higher than that of TDZ alone at 7, 14, and 21 days after application, respectively, demonstrating a sustained synergistic effect. Compared with 54% thiamethoxam compound, the defoliation rate of TDZ+GA treatment was 28.5%, 24.1%, and 13.4% higher at the three observation time points, indicating that its defoliation effect was superior to commercially available compound agents. Regarding the boll opening rate, although the differences among treatments were not statistically significant (…),… P >0.05), but the TDZ+GA treatment group achieved a boll opening rate of 78.8% 21 days after application, which was slightly higher than other treatment groups.

[0069] Experiment Example 8: Plant Experiment 1. Plant material (cotton) varieties: Zheda 18 and Sujimian 211. The seeds were provided by the Hainan Research Institute of Zhejiang University and the Institute of Economic Crops of Jiangsu Academy of Agricultural Sciences, respectively.

[0070] 2. Experimental treatments: There were 4 treatments in total: water control (CK); 15 g / mu of thiamethoxam (TDZ) aqueous solution; 0.8 g / mu of gibberellic acid (GA) oil suspension mixed with 15 g / mu of thiamethoxam (TDZ) aqueous solution (TDZ+GA); and 10 mL / mu of 54% thiamethoxam-dimethoxam compound aqueous solution. All treatments were applied by mixed spraying, with a water volume of 40 L / mu.

[0071] 3. The experiment was conducted in September 2025 at the Yangtze River Research Center of the China Cotton Research Institute in Huayang Town, Wangjiang County, Anhui Province. A split-plot design was used, repeated three times, with a total of 12 plots, each plot measuring 30 m². 2 The weather was sunny and windless on the day of application. A backpack sprayer was used to evenly spray all the leaves of the cotton plants in the plot. The leaf drop rate was investigated and counted 8, 15 and 25 days after application.

[0072] The defoliation rate is calculated using the following formula: Defoliation rate = (Number of cotton leaves before application - Number of cotton leaves after application) / Number of cotton leaves before application × 100%; In the above formula, the unit for defoliation rate is %.

[0073] The experimental results are shown in Table 2.

[0074] Table 2. Defoliation rate of cotton after different defoliation and ripening treatments in Wangjiang area. The TDZ+GA treatment effectively promoted defoliation in different varieties. In the Zhejiang University 18 variety, the TDZ+GA treatment group showed a 5.5% and 1.3% increase in defoliation rate at 8 and 15 days after application compared to the TDZ-only treatment, respectively; in the Suzhou Cotton 211 variety, the increases were 5.6% and 2.0%, respectively. Compared to the 54% thiamethoxam compound, the TDZ+GA treatment increased the defoliation rate by 0.8% at 8 days after application in the Zhejiang University 18 variety, and by 4.6% and 0.7% at 8 and 15 days after application in the Suzhou Cotton 211 variety, respectively, indicating that its effect in the early stage of defoliation is superior to commercially available compound agents. The response trends of the two varieties to the treatment were basically consistent, and the TDZ+GA treatment showed a good synergistic effect in different varieties.

[0075] Experiment Example 9: Plant Experiment 1. Plant material (cotton) variety: Lu Mian Yan 28, whose seeds were provided by Shandong Cotton Research Center.

[0076] 2. Experimental treatments: There were 4 treatments in total: water control (CK); 15 g / mu of thiamethoxam (TDZ) aqueous solution; 0.8 g / mu of gibberellic acid (GA) oil suspension mixed with 15 g / mu of thiamethoxam (TDZ) aqueous solution (TDZ+GA); and 10 mL / mu of 54% thiamethoxam-dimethoxam compound aqueous solution.

[0077] All treatments were applied using a mixed spraying method, with a water consumption of 40L / acre.

[0078] 3. The experiment was conducted in September 2025 at the research and experimental base of the Dezhou Academy of Agricultural Sciences in Shandong Province. A randomized block design was used, with three replicates, for a total of 12 plots, each plot measuring 25.08 m². 2 On the day of application, the weather was sunny. A backpack sprayer was used to evenly spray all the leaves of the cotton plants in the area. The leaf drop rate was investigated and counted 7, 17 and 30 days after application.

[0079] The defoliation rate is calculated using the following formula: Defoliation rate = (Number of cotton leaves before application - Number of cotton leaves after application) / Number of cotton leaves before application × 100%; In the above formula, the unit for defoliation rate is %.

[0080] The experimental results are shown in Table 3.

[0081] Table 3. Defoliation rate of cotton after different defoliation and ripening treatments in Dezhou area. There were highly significant differences in defoliation rates among the treatments. P <0.01). The TDZ+GA treatment group showed excellent defoliation effect 7 days after application, with a defoliation rate of 74.2%, significantly higher than TDZ alone (62.2%) and the thiamethoxam compound treatment (50.1%). At 17 days after application, the defoliation rate of the TDZ+GA treatment group increased to 86.6%. At 30 days after application, the defoliation rate of the TDZ+GA treatment group reached 90.5%, significantly higher than other treatments, demonstrating a sustained defoliation effect.

[0082] Notably, the TDZ+GA treatment showed a 19.3% higher defoliation rate in the early defoliation stage (7 days after application) compared to the TDZ alone treatment, indicating that the addition of gibberellic acid significantly accelerated the defoliation process. Compared to the thiamethoxam-diflubenzuron compound containing diuron, the TDZ+GA treatment demonstrated a significant advantage in defoliation rate at all observation stages, particularly during the critical defoliation period (7-17 days after application). These results indicate that the combination of gibberellic acid and thiamethoxam performs excellently in cotton fields in Dezhou, not only improving defoliation efficiency but also accelerating the defoliation process, providing a superior defoliation technology solution for cotton-growing areas in the Yellow River Basin.

[0083] Experiment Example 10: Plant Experiment 1. Plant material (cotton) variety: Jimian 30, whose seeds were provided by the Cotton Research Institute of Hebei Academy of Agricultural and Forestry Sciences.

[0084] 2. Experimental treatments: There were 4 treatments in total: water control (CK); 15 g / mu of thiamethoxam (TDZ) aqueous solution; 0.8 g / mu of gibberellic acid (GA) oil suspension mixed with 15 g / mu of thiamethoxam (TDZ) aqueous solution (TDZ+GA); and 10 mL / mu of 54% thiamethoxam-dimethoxam compound aqueous solution. All treatments were applied by mixed spraying, with a water volume of 40 L / mu.

[0085] 3. The experiment will be conducted in September 2025 at the Shangzhuang Experimental Station in Beijing. A randomized block design will be used, replicated four times, with a total of 16 plots, each plot measuring 30 m². 2 The weather was fine on the day of application, and the spraying was carried out once on September 23. A backpack sprayer was used to evenly spray all the leaves of the cotton plants in the plot. The leaf drop rate was investigated and counted 7, 14 and 23 days after the application.

[0086] The defoliation rate is calculated using the following formula: Defoliation rate = (Number of cotton leaves before application - Number of cotton leaves after application) / Number of cotton leaves before application × 100%; In the above formula, the unit for defoliation rate is %.

[0087] The experimental results are shown in Table 4.

[0088] Table 4. Cotton defoliation rate after different defoliation and ripening treatments in Shangzhuang area. Although the difference in defoliation rate among treatments did not reach a significant level ( P While the concentration of diuron was >0.05%, the TDZ+GA treatment group exhibited a stable defoliation effect. Seven days after application, the defoliation rate of the TDZ+GA treatment group was 38.9%, comparable to the 54% thiamethoxam-diflubenzuron compound treatment (40.1%). By days 14 and 23 after application, the defoliation rates of the TDZ+GA treatment group reached 48.6% and 66.1% respectively, slightly lower than the thiamethoxam-diflubenzuron compound treatment (54.0% and 69.1%), but still maintaining a good defoliation effect. It is worth noting that the TDZ+GA treatment completely avoids the use of diuron, achieving environmental friendliness while ensuring defoliation effectiveness, providing a feasible technical option for cotton defoliation in ecologically sensitive areas.

[0089] The results above demonstrate that gibberellic acid (GA), as a highly efficient and broad-spectrum synergist, significantly enhances the defoliation performance of thidiazuron (TDZ). It not only directly strengthens the defoliation effect and accelerates the defoliation and boll opening process, but also greatly improves the stability and reliability of this technology under different cotton varieties, varying climates (temperature, light, water), and complex field management conditions (nitrogen fertilizer, chemical control), thus providing a more resilient solution for mechanized cotton harvesting. From an application perspective, the combination of gibberellic acid and thidiazuron, while ensuring excellent agronomic effects, also exhibits significant advantages in terms of environmental friendliness and cost-effectiveness. These outstanding characteristics of "high efficiency, greenness, and economy" make this technical solution highly competitive in promoting the upgrading of mechanized cotton harvesting technology.

[0090] This invention fundamentally avoids environmental pollution risks by replacing diuron in mainstream formulations with the plant growth regulator gibberellic acid. Specifically, diuron, as a photosynthesis inhibitor herbicide, works by blocking the plant electron transport chain, exhibits broad-spectrum toxicity to non-target organisms, and has a long half-life in soil lasting several months, easily leading to soil residues and water pollution. In contrast, gibberellin, the main component of gibberellic acid formulations, is a natural growth hormone present in plants. It can be rapidly degraded into harmless substances by microorganisms in the environment, with a half-life of only a few days, making it ecosystem-friendly. Meanwhile, this invention achieves a synergistic effect between gibberellic acid and thiamethoxam through a specific ratio of 1:5 to 120. Gibberellic acid can significantly enhance and stabilize the defoliation effect of thiamethoxam. The combination of the two provides an alternative solution that does not rely on diuron while achieving the same or better defoliation and ripening effect. This achieves the dual goals of efficient defoliation and environmental protection, and can solve the problem of environmental pollution risks associated with the existing strategy of combining the mainstream defoliant thiamethoxam with the photosynthesis inhibitor herbicide diuron.

[0091] It should be noted that when numerical ranges are involved in this invention, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. To avoid redundancy, this invention describes preferred embodiments.

[0092] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments, all of which fall within the scope of the invention.

Claims

1. A cotton defoliation and ripening composition, characterized in that, The cotton defoliation and ripening composition includes gibberellic acid and thiamethoxam; The mass ratio of gibberellic acid to thiabendazole is 1:5~120.

2. The cotton defoliation and ripening composition according to claim 1, characterized in that, The formulation of the cotton defoliation and ripening composition is a wettable powder, water-dispersible granules, or suspension.

3. The cotton defoliation and ripening composition according to claim 2, characterized in that, The cotton defoliation and ripening composition also includes pesticide-acceptable adjuvants.

4. The cotton defoliation and ripening composition according to claim 3, characterized in that, The additives are selected from any one or more of surfactants, spray additives, deposition additives, anti-drift additives, and functional additives.

5. The use of the cotton defoliation and ripening composition according to any one of claims 1 to 4 in the defoliation and ripening of cotton.

6. The application according to claim 5, characterized in that, Apply the cotton defoliation and ripening composition 15 to 25 days before cotton harvest.

7. The application according to claim 6, characterized in that, The cotton defoliation and ripening composition is applied in stages or in combination.

8. The application according to claim 7, characterized in that, The step-by-step application process is as follows: First, prepare gibberellic acid into an aqueous solution and spray it. After an interval of 2 to 4 hours, prepare thiabendazole into an aqueous solution and spray it.

9. The application according to claim 7, characterized in that, The process of mixed application is as follows: After mixing gibberellic acid and thidiazuron in a mass ratio of 1:5~120 to form an aqueous solution, it is applied as a single spray.

Images