The stick tea thrip (Dendrothrips minowai Priesner) is the main pest thrip in tea (Camellia sinensis) plantations in China, and seriously affects the quality and yield of tea. Plant-derived semiochemicals provide an alternative to pheromones as lures and these compounds possess powerful attractiveness. In this study, we selected 20 non-pheromone semiochemicals, including compounds that have been reported to attract other thrips and some volatiles emitted from tea plants as the potential attractant components for D. minowai. In electroantennogram (EAG) assays, 10 synthetic compounds (p-anisaldehyde, 3-methyl butanal, (E)-β-ocimene, farnesene, nonanal, eugenol, (+)-α-pinene, limonene, (−)-α-pinene, and γ-terpinene) elicited significant antennal responses in female D. minowai. In addition, a two-choice H-tube olfactometer bioassay showed that D. minowai displayed significant positive responses to eight compound dilutions (p-anisaldehyde, eugenol, farnesene, methyl benzoate, 3-methyl butanal, (E)-β-ocimene, (−)-α-pinene, and (+)-α-pinene) when compared with the solvent control at both 1 and 2 h. Moreover, γ-terpinene exhibited a significantly deterrent effect on D. minowai. Finally, trap catches of four compounds (p-anisaldehyde, eugenol, farnesene, and 3-methyl butanal, respectively) significantly increase in tea plantations. Among these, the maximum number of D. minowai collected by blue sticky traps baited with p-anisaldehyde was 7.7 times higher than the control. In conclusion, p-anisaldehyde, eugenol, farnesene, and 3-methyl butanal could significantly attract D. minowai in the laboratory and under field conditions, suggesting considerable potential as commercial attractants to control D. minowai populations.

Pesticide application is the only known control method for the tea tortrix Archips strojny (Lepidoptera: Tortricidae), which is a major pest of spring tea in China. To develop sex pheromone-based, environmentally safe control strategies, here we identified the sex pheromone components of this species. The male moths’ antennae responded electrophysiologically to two compounds in female pheromone gland extracts. Gas chromatography–mass spectrometry analysis indicated that the two bioactive compounds were (Z)-11-tetradecenyl acetate (Z11-14:Ac) and (Z)-11-tetradecenyl alcohol (Z11-14:OH). Field trapping assays showed that lures baited with only the major component Z11-14:Ac were the most attractive to male moths, and the attractiveness decreased significantly when the lure was impregnated with increased relative ratios of the minor component Z11-14:OH. Our study demonstrated that Z11-14:Ac was the major attractant in the A. strojny sex pheromone, and the minor component Z11-14:OH seemed to serve as an antagonist. The results indicate that lures baited with 1 mg of Z11-14:Ac could be used as a monitoring or mass trapping tool for A. strojny management in Chinese tea plantations. Furthermore, Z11-14:Ac was identified as a common sex pheromone attractant of nine Archips species; these results lay the foundation for developing mating disruption techniques that target multiple leafroller pests.

The tea black tussock moth (Dasychira baibarana), a devastating pest in Chinese tea plantations, uses a ternary Type-II pheromone blend containing (3Z,6Z)-cis-9,10-epoxyhenicosa-3,6-diene (Z3,Z6,epo9-21:H), (3Z,6Z,11E)-cis-9,10-epoxyhenicosa-3,6,11-triene (Z3,Z6,epo9,E11-21:H), and (3Z,6Z)-henicosa-3,6-dien-11-one (Z3,Z6-21:11-one) for mate communication. To elucidate the P450 candidates associated with the biosynthesis of these sex pheromone components, we sequenced the female D. baibarana pheromone gland and the abdomen excluding the pheromone gland. A total of 75 DbP450s were identified. Function annotation suggested six CYPs were orthologous genes that are linked to molting hormone metabolism, and eight antennae specifically and significantly up-regulated CYPs may play roles in odorant processing. Based on a combination of comparative RNAseq, phylogenetic, and tissue expression pattern analysis, one CYP4G with abdomen specifically predominant expression pattern was likely to be the P450 decarbonylase, while the pheromone-gland specifically and most abundant CYP341B65 was the most promising epoxidase candidate for the D. baibarana sex pheromone biosynthesis. Collectively, our research laid a valuable basis not only for further functional elucidation of the candidate P450 decarbonylase and epoxidase for the sex pheromone biosynthesis but also for understanding the physiological functions and functional diversity of the CYP gene superfamily in the D. baibarana.

Scopula subpunctaria, an abundant pest in tea gardens, produce type-II sex pheromone components, which are critical for its communicative and reproductive abilities; however, genes encoding the proteins involved in the detection of type-II sex pheromone components have rarely been documented in moths. In the present study, we sequenced the transcriptomes of the male and female S. subpunctaria antennae. A total of 150 candidate olfaction genes, comprising 58 odorant receptors (SsubORs), 26 ionotropic receptors (SsubIRs), 24 chemosensory proteins (SsubCSPs), 40 odorant-binding proteins (SsubOBPs), and 2 sensory neuron membrane proteins (SsubSNMPs) were identified in S. subpunctaria. Phylogenetic analysis, qPCR, and mRNA abundance analysis results suggested that SsubOR46 may be the Orco (non-traditional odorant receptor, a subfamily of ORs) of S. subpunctaria. SsubOR9, SsubOR53, and SsubOR55 belonged to the pheromone receptor (PR) clades which have a higher expression in male antennae. Interestingly, SsubOR44 was uniquely expressed in the antennae, with a higher expression in males than in females. SsubOBP25, SsubOBP27, and SsubOBP28 were clustered into the moth pheromone-binding protein (PBP) sub-family, and they were uniquely expressed in the antennae, with a higher expression in males than in females. SsubOBP19, a member of the GOBP2 group, was the most abundant OBP in the antennae. These findings indicate that these olfactory genes, comprising five candidate PRs, three candidate PBPs, and one candidate GOBP2, may be involved in type II sex pheromone detection. As well as these genes, most of the remaining SsubORs, and all of the SsubIRs, showed a considerably higher expression in the female antennae than in the male antennae. Many of these, including SsubOR40, SsubOR42, SsubOR43, and SsubIR26, were more abundant in female antennae. These olfactory and ionotropic receptors may be related to the detection of host plant volatiles. The results of this present study provide a basis for exploring the olfaction mechanisms in S. subpunctaria, with a focus on the genes involved in type II sex pheromones. The evolutionary analyses in our study provide new insights into the differentiation and evolution of lepidopteran PRs.

Labor shortages in the Chinese tea industry have accelerated the need for crop protection unmanned aerial vehicles (CP-UAVs), which can greatly improve working efficiency. However, CP-UAV operational parameters must be optimized for effective pest control. In this study, the spraying performance of two CP-UAVs (DJI T30 and T40) under different operational parameters were compared in tea gardens. Additionally, the utility of CP-UAVs for controlling tea leafhoppers was investigated. Droplet coverage and size increased as the spray volume increased for both T30 (from 30 L·ha⁻¹ to 90 L·ha⁻¹) and T40 (from 60 L·ha⁻¹ to 150 L·ha⁻¹). Under the same operational parameters, spray deposition at the surface and inner part of the tea canopy was 1.4- and 2.9 times higher, respectively, for T40 than for T30. For T40, droplet penetrability increased significantly following decreases in working height (from 5 to 2 m) and driving speed (from 5 to 3 m·s⁻¹). The spray performance and control effect of T40 were significantly greater under optimal operational parameters (driving speed of 3 m·s⁻¹, working height of 2.5 m, and spray volume of 120 L·ha⁻¹) than under conventional application parameters (driving speed of 5 m·s⁻¹, working height of 4.5 m, and spray volume of 45 L·ha⁻¹). Using T40 under the optimal operational parameters decreased the amount of pesticide required to control tea leafhoppers by 25%, relative to the amount required for traditional knapsack sprayers. Furthermore, pesticide residue levels were similar for T40 and the knapsack sprayer. These findings provide valuable insights into the application of CP-UAVs in tea gardens, which may be important for further developing a modern, intensive, and sustainable tea industry.

The stick tea thrips, D. minowai Priesner (Thysanoptera: Thripidae), is one of the most economically significant thrips pests of tea (Camellia sinensis (L.) O. Ktze.) in China. Here, we sampled D. minowai in tea plantations from 2019 to 2022 to characterize its activity patterns, population dynamics, and spatial distribution. A large proportion of D. minowai individuals were caught in traps placed at heights ranging from 5 cm below to 25 cm above the position of tender leaves at the top of the tea plant, and the greatest number of individuals were captured at a height of 10 cm from the position of tender leaves at the top of the tea plant. Thrips were most abundant from 10:00 to 16:00 h in the spring and from 06:00 to 10:00 h and from 16:00 to 20:00 h on sunny days in the summer. The spatial distribution of D. minowai females and nymphs was aggregated on leaves according to Taylor’s power law (females: R² = 0.92, b = 1.69 > 1; nymphs: R² = 0.91, b = 2.29 > 1) and Lloyd’s patchiness index (females and nymphs: C > 1, Ca > 0, I > 0, M*/m > 1). The D. minowai population was dominated by females, and male density increased in June. Adult thrips overwintered on the bottom leaves, and they were most abundant from April to June and from August to October. Our findings will aid efforts to control D. minowai populations.