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For plant volatiles to mediate interactions in tritrophic systems, they must convey accurate and reliable information to insects. However, it is unknown whether the ratio of compounds in plant volatile blends remains stable during wind transmission. In this study, volatiles released from an odor source were collected at different points in a wind tunnel and analyzed. The variation in the amounts of volatiles collected at different points formed a rough cone shape. The amounts of volatiles collected tended to decrease with increasing distance from the odor source. Principal component analyses showed that the volatile profiles were dissimilar among different collection points. The profiles of volatiles collected nearest the odor source were the most similar to the released odor. Higher wind speed resulted in a clearer spatial distribution of volatile compounds. Thus, variations in the ratios of compounds in odor plumes exist even during transport over short distances.

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.

The tea tussock moth, Euproctis pseudoconspersa , is one of the most notorious tea plant pests globally. Herein, we assembled a high-quality chromosome level genome of E. pseudoconspersa using a combination of PacBio HiFi sequencing and Hi-C scaffolding. The genome size was 374.29 Mb and 99.94% of the assembled sequences were anchored onto 23 chromosomes with a contig N50 of 15.29 Mb and scaffold N50 of 16.84 Mb. The BUSCO completeness of the assembly was estimated to be 98.69%. The genome contained 132.74 Mb repeat sequences and 12 371 protein-coding genes. This high-quality genome provides a significant genetic resource for analyses of phylogenetic relationships and moth evolution, contributing to the development of pest management strategies.

Ectropis obliqua, a notorious tea pest, produces a Type-II sex pheromone blend for mate communication. This blend contains (Z,Z,Z)-3,6,9-octadecatriene, (Z,Z)-3,9-cis-6,7-epoxy-octadecadiene, and (Z,Z)-3,9-cis-6,7-epoxy-nonadecadiene. To elucidate the genes related to the biosynthesis of these sex pheromone components, transcriptome sequencing of the female E. obliqua pheromone gland and the abdomen without pheromone gland was performed. Comparative RNAseq analyses identified 52 putative genes, including 7 fatty acyl-CoA elongases (ELOs), 9 fatty acyl-CoA reductases (FARs), 1 decarbonylase (DEC), 3 lipophorins (LIPs), and 32 cytochrome P450 enzymes (CYPs). Tissue expression profiles revealed that two ELOs (ELO3 and ELO5), two FARs (FAR2 and FAR9), one DEC (CYP4G173), and one LIP (LIP1) displayed either abdomen-centric or -specific expression, suggesting potential roles in sex pheromone biosynthesis within the oenocytes of E. obliqua. Furthermore, the tissue expression patterns, combined with phylogenetic analysis, showed that CYP340BD1, which was expressed specifically and predominantly only in the pheromone gland, was clustered with the previously reported epoxidases, highlighting its potential role in the epoxidation of the unsaturated polytriene sex pheromone components. Collectively, our research provides valuable insights into the genes linked to sex pheromone biosynthesis.

Background Tea weevil, Myllocerinus aurolineatus Voss (Coleoptera: Curculionidae), is an important insect pest in Chinese tea plantations. The primary method for controlling tea weevils involves the use chemical pesticides. Hence, there is an urgent need for environmentally friendly control strategies. To screen for potential pathogenic strains useful for the biocontrol of tea weevils, a naturally occurring Metarhizium pingshaense strain was isolated from a field-collected infected tea weevil larva for the first time in China. Results Morphological features and molecular characteristics revealed the isolate was an M. pingshaense strain, herein referred to as Ma0628. At 22 °C (tea weevil pupation temperature), the inoculation with M. pingshaense Ma0628 resulted in a corrected cumulative late instar larval mortality rate exceeding 76% at 11 days after the inoculation with the 1 × 10 8 conidia/ml spore suspension using the immersion or soil-mixing method. Accordingly, the median lethal concentrations were 4.49 × 10 3 and 3.76 × 10 2 conidia/ml for the immersion and soil-mixing inoculation methods, respectively. Furthermore, the corrected cumulative adult mortality rate reached 83.33% at 14 days after the inoculation with the 1 × 10 8 conidia/ml spore suspension. Conclusion The study results indicate that M. pingshaense strain Ma0628 is an entomopathogenic fungus pathogenic to tea weevil larvae and adults, suggesting it may be a potentially useful biocontrol agent for preventing M. aurolineatus infestations.

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.

Helopeltis cinchonae is an emerging pest of tea and causes severe damage to tea plantations in China. The female of H. cinchonae has been reported to produce a sex pheromone consisting of two components, hexyl (3R)-3-acetoxybutyrate and (5R)-1-acetoxy-5-butyroxyhexane, and lures containing the synthetic compounds have been shown to attract male H. cinchonae to traps in the field. This is the first time that components of the sex pheromone have been identified for a species of Helopeltis bug, but their field application has not been evaluated in detail. The present study shows that a blend of both compounds loaded into a polyethylene vial at 0.2 and 2 mg, respectively, caught significantly more male H. cinchonae bugs than the individual compounds and all the other tested blends. Sticky wing traps baited with the binary blend of compounds at the optimized ratio and dosage caught more bugs than bucket funnel or delta traps, and traps hung at a height of 10 cm above the tea shoots caught more bugs than those at other heights. The optimized traps and lures were used for monitoring the pest and two distinct population peaks of H. cinchonae were observed, the first one during mid-May to early June, and the other one in mid-September. Overall, the results of this study contribute to an environmentally-friendly approach to monitoring and managing H. cinchonae in the field.

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.

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 thrip (Dendrothrips minowai) is one of the most serious sucking pests of tea plants (Camellia sinensis) in China, North Korea, and Japan. Plant volatile lures are widely used for both monitoring and mass trapping. Previously, we demonstrated that sticky traps baited with p-anisaldehyde, eugenol, farnesene, or 3-methyl butanal captured significantly more D. minowai in tea plantations, with p-anisaldehyde notably capturing the most. In this study, we showed that D. minowai adults exhibited significantly higher attraction to mixtures of p-anisaldehyde, eugenol, and farnesene compared to an equivalent dose of p-anisaldehyde alone in H-tube olfactometer assays under laboratory conditions. Moreover, in field experiments conducted in 2022, rubber septa impregnated with a ternary blend of p-anisaldehyde, eugenol, and farnesene (at 3–4.5 mg and a ratio of 3:1:1) captured the highest number of adults on sticky traps, outperforming traps bailed with individual components or a solvent control over two weeks. Significantly, the mass trapping strategy employing these lures achieved control efficacies ranging from 62.8% to 70.7% when compared to traps without attractant, which achieved control efficacies of only 14.2% to 35.4% across three test sites in 2023. These results indicate that the combination of p-anisaldehyde, eugenol, and farnesene exhibits an additive or synergistic effect on D. minowai. In conclusion, our findings establish a theoretical framework and provide practical technological support for integrating attractant-based strategies into comprehensive thrips management strategies.