As an important economic crop in China, the development of the cotton industry plays a crucial role in the agricultural economy. Among them, the Xinjiang cotton industry occupies a core position in the country. According to data from the National Bureau of Statistics, in 2024, the sown area of cotton in Xinjiang reached 2.4479 million hectares, with a yield of 5.686 million tons, accounting for 86.25% and 92.25% of the national total sown area and total yield of cotton respectively, making it a key region determining the national cotton production capacity. Pesticides, as important production materials for preventing and controlling diseases and pests and regulating growth in the cotton production process, their registration management and application directly relate to the high-quality and efficient development of the cotton industry. China implements a pesticide registration management strategy that emphasizes both safety and efficacy. Combined with the characteristics of the cotton growth period, pesticide application is concentrated from April to August, covering multiple types of products such as herbicides, insecticides, fungicides, plant growth regulators, and defoliants/ripening agents, with a high frequency of application. For example, the number of applications for controlling cotton aphids can reach 6-10 times, and in some areas with severe aphid infestations, the number exceeds 10 times, which fully reflects the core supporting role of pesticides in cotton production.

As of October 28, 2024, a total of 2,822 types of pesticides have been registered for cotton in China, covering six categories: seed dressings, herbicides, insecticides, acaricides, fungicides, and plant growth regulators. Although this figure is slightly lower than the 3,027 registered pesticides for corn, when compared with the sown area, the sown area of corn in 2023 was 44.2 million hectares, while that of cotton was only 2.7881 million hectares. The number of registered pesticides per unit sown area is significantly higher for cotton, reflecting the industrial characteristics of cotton having a wide variety of harmful organisms and complex control needs. The following will conduct a detailed analysis on the registration details, functional characteristics, and application scenarios of various types of pesticides.

I. Seed Treatment Agents: The First Line of Defense for Seedling Protection

As an important means to reduce pesticide use and increase efficiency, seed treatment agents have a long application history in China. Relevant records can be found in the "Fan Shengzhi Shu" (a classic agricultural book) compiled during the Western Han Dynasty. Since the 1950s, seed soaking and dressing technologies have been promoted on a large scale. By forming a protective film on the seed surface, they can not only resist the invasion of soil-borne diseases and pests but also slowly release active ingredients during the seed germination and plant growth process, which are absorbed by the crops. They have the advantages of convenient use, labor and pesticide saving, and environmental protection.

As of October 28, 2024, the number of registered cotton seed treatment agents has reached 141, which can be divided into 70 insecticides, 58 fungicides, 12 insecticide-fungicides, and 1 plant growth regulator by function. Insecticides are mainly imidacloprid and thiamethoxam single preparations, with the core control target being cotton aphids, and some products can also control thrips. Fungicides have a variety of components, mainly targeting common seedling diseases such as damping-off and blight. Insecticide-fungicides are mostly compound preparations of neonicotinoid insecticides and various fungicides (such as fludioxonil, metalaxyl-M, azoxystrobin, thiram, carbendazim, carboxin, pyraclostrobin, etc.), which realize the simultaneous control of diseases and pests. There is only 1 plant growth regulator in cotton seed treatment agents, with chitosan as the active ingredient, used to regulate cotton growth, indicating that the application of this type of agent in the seed treatment link is still relatively limited.

II. Herbicides: A Key Control Link for Ensuring Yield

Weeds are important factors restricting the high-quality and high-yield of cotton. The occurrence area of weeds in cotton fields accounts for 56%, causing a yield loss of 14%-16% every year, and the yield loss can reach 50% in severely affected areas. Weeds not only compete with cotton for water, heat, light, nutrients and other resources but also easily become intermediate hosts for diseases and pests, increasing the input of material and chemical costs in cotton fields. There are abundant types of weeds in Chinese cotton fields, covering 60 species in 25 families. With the increase of continuous cropping years in Xinjiang cotton fields, the occurrence frequency of weeds increases year by year, and the control pressure continues to increase.

Among the 317 registered cotton herbicides, there are 212 soil spray types (including 165 pre-sowing and 47 post-sowing pre-emergence) and 105 foliar spray types, forming a complete control system of "closed application + foliar treatment". Pre-sowing soil spray herbicides are mainly pendimethalin, flumioxazin, etc., used to control annual gramineous weeds and some broad-leaved weeds. Post-sowing pre-emergence closed herbicides include prometryn, acetochlor, etc., covering various annual weeds. Among the foliar spray types, 79 are used for weed control at the 3-5 leaf stage, mainly oxalic acid, haloxyfop-R-methyl, etc., focusing on annual gramineous weeds. 21 directional spray herbicides are mainly glyphosate series, targeting annual and perennial weeds. In addition, there are a small number of herbicides targeting broad-leaved weeds at specific leaf ages, reflecting the precise orientation of herbicide registration.

III. Fungicides: Professional Support for Disease Control

Cotton is vulnerable to infection by various pathogens such as fungi, bacteria, and viruses during its growth. More than 80 types of cotton diseases have been recorded in China, among which more than 20 cause severe damage, resulting in an average annual yield loss of 15%-20%. As the main production area, Xinjiang cotton fields are mainly faced with seedling diseases such as damping-off and blight, fusarium wilt and verticillium wilt that occur throughout the growth period, and occasional boll diseases. Different diseases have significantly different control methods: seedling diseases are mainly controlled by seed coating, while soil-borne vascular diseases such as fusarium wilt and verticillium wilt require root irrigation or drip irrigation for pesticide application, with a large amount of pesticide used.

The 151 registered fungicides form a targeted disease control system: 83 are for seedling diseases, mainly carbendazim, tolclofos-methyl, etc.; 19 are for blight, 18 for fusarium wilt, and 16 for verticillium wilt. Among them, biological agents such as Bacillus subtilis and amino-oligosaccharide account for a certain proportion, which is in line with the trend of green control. There are relatively few registered fungicides for specific diseases such as anthracnose and phytophthora blight, with 3 types each, and only 1 registered fungicide for minor diseases such as brown spot and red rot, reflecting the characteristic that registration resources are inclined to major diseases.

IV. Insecticides and Acaricides: Core Guarantee for Pest Control

Pest damage occurs throughout the entire growth period of cotton for up to 5 months, which is the main direct factor causing yield loss. With the large-scale promotion of Bt insect-resistant cotton, lepidopteran pests such as cotton bollworm have become minor pests, while cotton aphid, cotton mirid bug, thrips, and cotton spider mite have become major control targets, and the pest control system has been adjusted accordingly. As of October 28, 2024, the total number of registered cotton insecticides and acaricides has reached 1,890, including 1,803 insecticides, 49 insecticide-acaricides, and 38 acaricides, forming a large control agent library.

From the perspective of control targets, there are significant differences between major and minor pests in registered agents: there are 1,222 agents for controlling cotton bollworm. Although its damage has decreased, it still has a quantitative advantage due to historical control needs and the broad spectrum of agents. The active ingredients include phoxim, emamectin benzoate, and biological agents such as Bacillus thuringiensis. As the current major pest, cotton aphid has 523 registered agents, mainly neonicotinoid agents such as imidacloprid and acetamiprid. There are 114 agents for controlling spider mites, with core ingredients such as amitraz and hexythiazox. It is worth noting that there are only 4 registered agents for thrips, which have caused increasing damage in recent years, while there are 51 agents for mirid bugs. This reflects that there is a certain lag in the connection between agent registration and the occurrence trend of pests, and it is expected that the number of registered agents for thrips control will increase significantly in the future. In addition, there are relatively few registered agents for minor pests such as whitefly and Liriomyza sativae, mostly 1-3 types, reflecting the differentiation of control priorities.

V. Plant Growth Regulators: Important Support for the Upgrade of Cultivation Modes

Since the formation of the "dwarf, dense, early-maturing" cultivation mode for Xinjiang cotton production around 1994, which is based on reasonable close planting, plant dwarfing, and early emergence and maturity, it has gradually become the dominant cultivation technology. This mode takes promoting early emergence and maturity as the main goal, makes full use of chemical regulation, and through close planting and dwarfing management to promote early growth, coordinates the growth and development with light energy utilization, balances the contradiction between individual and population, and improves the effective photosynthetic area and photosynthetic production capacity. With the maturity of the "dwarf, dense, early-maturing" cultivation mode, the frequency and dosage of plant growth regulators have gradually increased. Cotton needs to be sprayed with plant growth regulators multiple times starting from the seedling stage to improve stress resistance and shape a good plant type, thereby increasing yield and adapting to mechanical harvesting. In addition, cotton defoliation and ripening technology is a prerequisite for realizing mechanical cotton harvesting. The reasonable application of defoliants and ripening agents can not only solve the problems of late maturity due to overgrowth or inconsistent maturity in the later stage of cotton but also accelerate the leaf abscission before harvesting, improve the harvesting rate and operation efficiency of cotton pickers, and reduce the impurity content of machine-harvested seed cotton.

The 323 registered plant growth regulators form a complete functional system: 144 are used for growth regulation throughout the growth period, mainly mepiquat chloride, gibberellic acid, chlormequat chloride, flumetralin, and brassinolide, etc., to realize plant type shaping and stress resistance improvement; 20 are used for increasing yield and boll setting rate, with gibberellic acid as the core active ingredient; 101 are defoliants, mainly thidiazuron single preparations and compound preparations of thidiazuron and diuron, which realize leaf abscission by promoting the formation of abscission layers between petioles and stems and inhibiting photosynthesis; 57 are ripening agents, mainly ethephon, to ensure the concentrated boll opening of cotton. In addition, there is 1 diquat product registered as a cotton desiccant in the category of plant growth regulators, which is used when about 60% of cotton bolls crack naturally in the later growth stage to promote cotton boll opening, providing comprehensive technical support for mechanical cotton harvesting.

VI. New Registration Trend in Recent Years: Orientation towards Environmental Protection and Precision

According to the provisions of the "Pesticide Management Regulations" and "Pesticide Registration Management Measures", the validity period of pesticide registration certificates is 5 years. From the perspective of the expiration of new cotton pesticide registrations from 2024 to 2030, there will be a peak of expirations in 2028-2029, corresponding to a significant increase in the number of new cotton pesticide registrations in 2022-2023, reflecting the increased enthusiasm of the industry for registration after the implementation of the new pesticide policy. At the same time, the continuous improvement of social attention and requirements for pesticide use has promoted the development of the pesticide industry towards a more environmentally friendly and safer direction. In terms of the formulations of newly registered pesticides for cotton, environmentally friendly formulations such as soluble concentrates, suspension concentrates, oil-dispersible concentrates, water-dispersible granules, microcapsule suspension concentrates, microemulsions, and aqueous solutions are more than non-environmentally friendly formulations, which is in line with the trend of green agricultural development.

Conclusion

In 2024, the registration of pesticides for cotton in China presents the characteristics of "rich types, complete functions, and prominent priorities". The 2,822 registered pesticides cover the entire production links such as seed treatment, weed control, disease control, pest control, and growth regulation, providing a solid guarantee for the high-quality development of the Xinjiang cotton industry. From the perspective of the registration structure, insecticides and acaricides occupy a dominant position, reflecting the core demand for pest control; the number of registered plant growth regulators is sufficient, adapting to the "dwarf, dense, early-maturing" cultivation mode and the needs of mechanical cotton harvesting; seed treatment agents and herbicides have formed a systematic control system, while fungicides focus on major diseases. In the future, with the increasing damage of emerging pests such as thrips and the improvement of green development requirements, it is expected that the registration of cotton pesticides will show a development trend of "enhanced targeting, increased proportion of biological agents, and optimized environmentally friendly formulations", further supporting the quality and efficiency improvement and sustainable development of the cotton industry.