To reduce pesticide residues in Tea, tea scientists have developed many non-chemical methods for pest and disease control, one of which is the relatively mature technology of sex pheromone control.

1. Application of Sex Pheromone Monitoring in Pest Control on Tea Plants

The tea looper is a significant defoliating pest of tea plants in China. When severe, its larvae can consume all the leaves of a tea plant. In recent years, it has caused considerable damage in localized areas of Hainan, Hunan, Anhui, and Guangdong provinces. The Chinese Academy of Agricultural Sciences' Tea Research Institute analyzed and identified the sex pheromones of the tea looper in Hainan and Anhui provinces and established a formula for a sex attractant suitable for monitoring this pest. Using this sex attractant, continuous monitoring of the tea looper was conducted for six months in tea gardens in Wuzhishan, Hainan province. The results confirmed that using sex pheromones to monitor the tea looper is an accurate and efficient method. The monitoring data showed that there are two generations of the tea looper in the Wuzhishan area from May to October. The first generation of adults was observed on May 7, with low population density persisting for about a month until an increase on June 7. The population peaked on June 17, and ten days later, the density decreased. The second generation of adult populations began to increase on July 27, peaking on August 7, with the peak lasting longer than the first generation before declining after September 7.

Traditionally, black light traps were used for monitoring pests in Japanese tea gardens. However, since the identification of Tea Garden pest sex pheromones, these pheromones have been gradually applied in monitoring devices for tea pests. Currently, sex attractants are widely used to monitor pests such as the tea tortrix moth, long-horned tortrix moth, narrow tortrix moth, and the mulberry scale. For over 30 years, the National Institute of Horticultural and Herbal Science's Plant Protection Research Group has used sex attractants to monitor the three major pests — the tea tortrix moth, long-horned tortrix moth, and narrow tortrix moth — in the Shizuoka region, accumulating a vast amount of data to guide pest control and research on population ecology.

Commercially available sex pheromone products for pest monitoring in Japanese tea gardens

2. Application of Mating Disruption Using Sex Pheromones in Pest Control on Tea Plants

The tea tortrix moth is a significant pest of tea shoots and leaves, causing up to 20% yield loss in Japanese tea gardens. Therefore, extensive research has been conducted on this pest in Japan. In 1983, a sex pheromone disruptant for the tea tortrix moth became commercially available and was widely promoted in Shizuoka Prefecture. Both the tea tortrix moth and the long-horned tortrix moth contain (Z)-11-tetradecen-1-yl acetate in their sex pheromones, which was used as a general disruptant for both species. Initially, the mating disruption effect of this sex pheromone was 96%.

After more than a decade of use, the effectiveness of mating disruption declined to below 50%. In regions where sex pheromone mating disruption had been used for a long time, the tea tortrix moth developed resistance to (Z)-11-tetradecen-1-yl acetate, making male moths less sensitive to low doses of this compound. To overcome the resistance to single-component disruptants, adding other three sex pheromone components of the tea tortrix moth at specific ratios increased the effectiveness of mating disruption against resistant populations to 99%. A new disruptant for the tea tortrix moth was registered and sold in Japan. Recently, Japanese scientists developed a disruptant rope based on the original disruptant thread. The advantage of the new product is that it no longer requires the uniform hanging of a large number of disruptant threads throughout the tea garden; instead, only a rope needs to be placed around the tea garden, further reducing labor costs.

3. Application of Lure-and-Kill Technology Using Sex Pheromones in Pest Control on Tea Plants

Currently, the largest and most successful application of sex pheromone lure-and-kill technology is for the gray tea geometrid moth. After the sex pheromone of the gray tea geometrid moth was identified, the Chinese Academy of Agricultural Sciences' Tea Research Institute conducted comprehensive research on the lure-and-kill technology, studying the optimal ratio, dose, slow-release carrier, trap type, trap height, and spacing between traps. This led to the development of a complete lure-and-kill technology: the two effective components of the gray tea geometrid moth sex pheromone at a 4:6 ratio, with a dose of 1 mg, showed the best attraction activity; the sex pheromone released through an isoprene rubber plug had the best attraction effect on male gray tea geometrid moths, better than that achieved with silicone plugs or PVC capillary tubes; among various trap types tested, the boat-shaped trap was found to be the most suitable for attracting gray tea geometrid moths; when the trap was placed 25 cm above the tea plants, the attraction effect was optimal; and a distance of 15 m between traps resulted in the highest trapping efficiency.

Long-term monitoring revealed that the lure-and-kill technology using sex attractants effectively controlled the density of adult gray tea geometrid moths. Out of 24 surveys conducted from April to October, 15 showed significantly lower pest densities in treated areas compared to control areas, particularly during the peak emergence period of each generation, which significantly reduced the density of male adults and the mating success rate of females. Further field efficacy trials showed that using the gray tea geometrid moth sex attractant to control one generation of adults resulted in a 49.27% reduction in the next generation's larval population, while continuous control of two generations of adults resulted in a 67.16% reduction. Due to the excellent efficacy and environmental friendliness of the gray tea geometrid moth sex pheromone lure-and-kill technology, its application area has steadily increased since small-scale demonstration and promotion began in 2025. Currently, it has been applied across 17 provinces (municipalities), covering an area exceeding 10,000 hectares.

Outlook

The tea industry is a leading agricultural sector in China, playing a crucial role in rural economies, farmer income, and export earnings. Due to the good economic returns from tea, farmers have relied excessively on chemical pesticides to ensure stable yields, posing risks and challenges to tea quality and safety. Although the current quality standards of tea are high compared to other agricultural products, as a health beverage, consumers demand even stricter safety standards. Therefore, there is an urgent need for new control technologies to replace or reduce the use of chemical pesticides. Using sex pheromones to control harmful insects is a viable approach to effectively manage pests while protecting the environment. Pest control using insect sex pheromones has the advantages of high sensitivity, good control efficacy, ease of use, no environmental pollution, no harm to natural enemies, and low cost.

In recent years, tea plant protection scientists have conducted research on identifying sex pheromones of tea pests, developing efficient formulas, creating effective accompanying devices, researching application technologies, and elucidating courtship communication mechanisms. Sex pheromone products for tea pests have become increasingly series-oriented, the supporting application technologies have become more mature, and the application areas have expanded. It is believed that under the backdrop of green development, the use of sex pheromones in controlling tea pests will continue to grow.