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Simple Summary: The tea green leafhopper, Empoasca flavescens Fabrecius, is the most notorious pest in Chinese tea plantations, predominantly controlled through pesticide applications for decades. Recognizing the pressing need for novel, effective, and eco-friendly strategies to manage leafhoppers, this study aims to contribute to the reduction in pesticide usage in the tea industry. Salivary protein research is pivotal for gaining insights into effectors or elicitors, facilitating the exploration of novel regulatory targets and pathways in tea green leafhoppers. In this study, saliva from adult tea green leafhoppers was collected using a self-made collection device equipped with two layers of Parafilm stretched over a sucrose diet. Following freeze drying and filter-aided sample preparation (FASP), liquid chromatography–tandem mass spectrometry (LC-MS/MS) was employed to analyze the saliva proteins. Bioinformatics methodologies were then leveraged to predict the secretory proteins. The results suggest that the interactions between leafhoppers and tea plants, particularly in terms of feeding and defense responses, may be mediated by elicitors or effectors, such as mucin-like protein (EfMucin), vitellogenin (EfVg), odorant-binding protein (EfOBP), and others. The conclusive outcomes of this study provide new insights into the coevolutionary dynamics between tea plants and leafhoppers, offering novel pathways for the development of advanced leafhopper control technologies. Saliva plays a crucial role in shaping the compatibility of piercing–sucking insects with their host plants. Understanding the complex composition of leafhopper saliva is important for developing effective and eco-friendly control strategies for the tea green leafhopper, Empoasca flavescens Fabrecius, a major piercing–sucking pest in Chinese tea plantations. This study explored the saliva proteins of tea green leafhopper adults using a custom collection device, consisting of two layers of Parafilm stretched over a sucrose diet. A total of 152 proteins were identified using liquid chromatography–tandem mass spectrometry (LC-MS/MS) following the filter-aided sample preparation (FASP). These proteins were categorized into six groups based on their functions, including enzymes, transport proteins, regulatory proteins, cell structure proteins, other proteins, and unknown proteins. Bioinformatics analyses predicted 16 secreted proteins, which were successfully cloned and transcriptionally analyzed across various tissues and developmental stages. Genes encoding putative salivary secretory proteins, including Efmucin1, EfOBP1, EfOBP2, EfOBP3, Efmucin2, low-density lipoprotein receptor-related protein (EfLRP), EFVg1, and EFVg2, exhibited high expressions in salivary gland (SG) tissues and feeding-associated expressions at different developmental stages. These findings shed light on the potential elicitors or effectors mediating the leafhopper feeding and defense responses in tea plants, providing insights into the coevolution of tea plants and leafhoppers. The study's conclusions open avenues for the development of innovative leafhopper control technologies that reduce the reliance on pesticides in the tea industry. [ABSTRACT FROM AUTHOR]

Abstract Background Nowadays, instead of chemicals, using microbial pesticides is very important and significant to protect the environment. Verticillium lecanii (Z), the entomopathogenic fungus, is widely used for management of many pests. The aim of this work is to determine whether the small leafhopper, Empoasca flavescens F. (Homoptera: Cicadellidae), can be exterminated only by biopesticide—V. lecanii or not. Results After spraying with diluted suspension of V. lecanii spores on the small leafhopper, E. flavescens, the effects of infection and reinfection in accordance with the time, spore density and growth stage of the small leafhoppers were studied. When E. flavescens was sprayed with over 1.25 × 108 spores/ml of diluted suspension of fungal spores indoors, the reduction % was over 80% after 5 days and the decrease of imagoes was higher than that of larvae. Outdoors, E. flavescens was reduced by 50% for 3 years after treatment, while the reduction % was about 90% by reinfection year by year. Conclusion Ninety percentages of E. flavescens on peach trees can be effectively exterminated in 2 years by spraying the diluted suspension of V. lecanii spore, and no chemical pesticides are needed for the control of E. flavescens in practice.

Empoasca flavescens Fabricius is one of the most important sucking pests of tea. Earlier this pest was considered as minor pest of tea. But this has become a serious pest in Sub-Himalayan tea plantations of West Bengal, India. In spite of routine application of insecticides there were some incidences of management failure of this pest. Considering the importance of the problem to the tea industry, the present experiments were conducted with the objectives to study the insecticide susceptibility status of E. flavescens and to study the role of Glutathione S-transferase activity. Three commonly used neonicotinoids and three synthetic pyrethroids i.e., total six insecticides were tested against five populations of E. flavescens. Bioassay experiments were conducted with the field collected populations and Glutathione S-transferase activities were estimated. Resistance to the tested insecticides was very low (< 2.5-fold). It seems that resistance development against the tested insecticides was in initial stage. Thiamethoxam was found to be the least toxic insecticide and clothianidin was the most toxic insecticide. Higher activity of GST was found to be associated with the reduced susceptibility against the tested insecticides. As very low level of resistance against the tested insecticides was detected, use of these insecticides may be continued for management of tea greenfly but chemicals having similar mode of action should not be used repeatedly. Clothianidin and deltamethrin were found to be the two potent molecules against tea greenfly. [ABSTRACT FROM AUTHOR]

The tea green leafhopper, Empoasca flavescens, is a major pest of tea Camellia sinensis (L.) Kuntze. Until recently, it has mainly been controlled by pesticides, but their use has led to high levels of toxic residues in plants, which threaten both the environment and human health. Therefore, a safer biological control approach is needed. Tea plants produce many volatile compounds, and different tea clones differ in their resistance to the pest. We explored the possibility that volatile compounds influence the resistance of tea. Here, we assessed the resistance of 15 clones of tea plants to the pest, the volatile compounds produced by the clones, and the effects of the compounds on E. flavescens behavior. Six clones were classified as resistant, eight as moderately susceptible, and one as susceptible. Fresh leaf samples from resistant and susceptible clones were analyzed using HS–SPME–GC–MS. Sesquiterpenes and monoterpenes were two major groups characterized, representing 30.15% and 26.98% of the total compounds, respectively. From our analysis, we conclude that 3-hexen-1-ol, 2,6-dimethyleneoct-7-en-3-one, humulene, β-bourbonene, styrene, and benzaldehyde were important for the resistance and susceptibility of the clones. In a bioassay, E. flavescens were attracted to β-ocimene and methyl salicylate, but avoided linalool compounds. [ABSTRACT FROM AUTHOR]

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BACKGROUND The tea green leafhopper, Empoasca flavescens is the most important pest in Chinese tea plantations. For decades its control has been executed almost exclusively through pesticide applications. A semiochemical‐based 'push–pull' strategy was tested on the leafhopper in the study. RESULTS: The odors released from Tagetes erecta and Flemingia macrophylla significantly repelled and attracted leafhoppers, respectively. These volatile compounds (46 from T. erecta and 53 F. macrophylla) were identified and quantified via gas chromatography–mass spectometry (GC–MS) analysis. Y‐tube olfactometer assays indicated that thymol anisole, thymol and camphor had significant repellent effects on the leafhoppers, resulting in a ternary repellent blend at a 4:3:13 ratio. Cis‐3‐hexen‐1‐ol, cis‐3‐hexenyl acetate, nonanal and α‐farnesene were significantly attractive to the leafhoppers, making an attractant blend at a 17:4:1:1 ratio. In the field, the push–pull strategy with the repellent dispensers placed within the tea bushes and the attractant‐baited sticky traps hung 15 cm above the tea plants showed a significant control efficacy, reaching 69% and 55% at two and 14 days post‐treatment, respectively, similar to those in the insecticide control plots. Additionally, the leafhopper density in the push–pull intercropping plot was 63.2 leafhoppers/100 tea shoots/visit, much lower than those in the pull intercropping plot and nonintercropping plot. CONCLUSION: Application of the push–pull strategy using both synthetic repellent and attractant, or intercropping T. erecta and F. macrophylla with tea plants, can effectively reduce the leafhopper population. This approach might have great potential as an environmentally safe control strategy against the leafhopper. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The influence of different dates of sowing and various weather variables was studied on some major insect pests attacking the economically important castor crop. The susceptible castor hybrid DCH 177 was cultivated on six different dates of sowing at fortnightly interval during May–August, 2018. Crop sown during late May and first fortnight of June (i.e., the "very early sowing" and the "the early sowing") were found to be least infested by Empoasca flavescens but severely infested with S. litura larvae and the capsule damage by Conogethes punctiferalis was also very high in these two sowing dates as compared to crop sown at other dates. Maximum incidence of E. flavescens and Achaea janata was noticed in late sowings. Correlation analysis revealed that the evening relative humidity influenced the leafhopper nymphal population significantly whereas, the capsule damage by C. punctiferalis was significantly influenced by the minimum temperature and wind velocity. The influence of weather parameters on larval population of A. janata and Spodoptera litura was found statistically non-significant. The study highlights the significance of sowing date in the insect pest management scenario by defining the ultimate degree of infestation levels of insect pests. [ABSTRACT FROM AUTHOR]

The tea green leafhopper, Empoasca flavescens, is a major pest of tea Camellia sinensis (L.) Kuntze. Until recently, it has mainly been controlled by pesticides, but their use has led to high levels of toxic residues in plants, which threaten both the environment and human health. Therefore, a safer biological control approach is needed. Tea plants produce many volatile compounds, and different tea clones differ in their resistance to the pest. We explored the possibility that volatile compounds influence the resistance of tea. Here, we assessed the resistance of 15 clones of tea plants to the pest, the volatile compounds produced by the clones, and the effects of the compounds on E. flavescens behavior. Six clones were classified as resistant, eight as moderately susceptible, and one as susceptible. Fresh leaf samples from resistant and susceptible clones were analyzed using HS–SPME–GC–MS. Sesquiterpenes and monoterpenes were two major groups characterized, representing 30.15% and 26.98% of the total compounds, respectively. From our analysis, we conclude that 3-hexen-1-ol, 2,6-dimethyleneoct-7-en-3-one, humulene, β-bourbonene, styrene, and benzaldehyde were important for the resistance and susceptibility of the clones. In a bioassay, E. flavescens were attracted to β-ocimene and methyl salicylate, but avoided linalool compounds.

Tea is prepared from the tender leaves and buds of Camellia sinensis (L.). In sub-Himalayan tea plantations of North-East India, different management practices are followed to protect the tea crop against different sucking insect pests such as Helopeltis theivora (Hemiptera: Miridae), Empoasca flavescens (Homoptera: Cicadellidae) and Scirtothrips dorsalis (Thysanoptera: Thripidae). Most plantations are managed conventionally through the use of different organo-synthetic insecticides, whereas some are managed organically by using herbal and microbial insecticides. In conventional tea plantations, organo-synthetic insecticides of different functional groups (organochlorines, organophosphates, synthetic pyrethroids and neonicotinoids) are routinely applied round the year to keep the sucking insect pest populations under control. A variety of defence mechanisms, including enzymatic detoxification systems (carboxylesterases, glutathione S-transferases and cytochrome P450 monooxygenases), physiological tolerance and behavioural avoidance, protect insect herbivores from these hazardous compounds. Insect pests have evolved mechanisms to degrade metabolically (enzymatically) or otherwise circumvent the toxic effect of many types of chemicals synthesized as modern insecticides. The extent to which insects can metabolize and thereby degrade these toxic or otherwise detrimental chemicals is of considerable importance for their survival in an unfriendly chemical environment. These mechanisms continue to evolve as insects attempt to colonize new plant species or encounter newer molecules of synthetic insecticides. The level and type of detoxifying mechanisms differs greatly, which, therefore, results in varying toxicity among different stages, species and populations. Variation in detoxifying enzyme activity is responsible, in part, at least for the selective toxicity of different insecticides, the development of resistance to insecticides and the selection of host plants. Overexpression of these detoxifying enzymes, capable of metabolizing insecticides, can result in higher levels of metabolic tolerance/resistance to synthetic insecticides. [ABSTRACT FROM PUBLISHER]

Efficacy of some promising botanicals and the synergists were compared to the commonly used chemical dichlorvos (76EC) against jassid Empoasca flavescens F. infesting mulberry as well as their biosafety to natural enemies. Among the botanicals, sole application of neem oil (3%), FORS (2%) and pongamia oil (3%) recorded 48.73, 46.88 and 42.49% reduction in jassid population respectively, whereas the NSKE (5%) exhibited least among all (33.59% at 1 DAS).The synergistic effect of neem oil and FORS recorded the best, 72.64% reduction followed by Pongamia oil + FORS (62.81%) and neem oil + pongamia oil (60.16%). Though dichlorvos was effective than all treatments (88.57% reduction) the chemical also eliminated more than 90% population of predatory coccinellids and spiders but the botanicals found relatively safer. Hence, the combination of neem oil (3%) with fish oil rosin soap (2%) could be used as an alternate to dichlorvos to manage jassid menace in mulberry as well as to conserve the natural enemies. [ABSTRACT FROM AUTHOR]

Empoasca flavescens Fabricius (Homoptera: Cicadellidae), is an emerging insect pest of tea, Camelia sinensis L. (Theaceae), in sub-Himalayan region of West Bengal. Use of synthetic insecticides in tea plantations against insect pests may have resulted in development of resistant E. flavescens populations. This was tested by recording genetic variations in the populations of E. flavescens collected from three different locations of North Bengal. Three populations were studied using RAPD-PCR. Polymorphism in populations was assayed using eight random primers resulting in amplification of 53 loci. The polymorphic loci recorded were 83.02, 84.92 and 88.68 % in Darjeeling hill, Terai and the Dooars populations, respectively. The genetic distance between Darjeeling hill and Terai, Darjeeling hill and the Dooars populations were found to be 0.0255 and 0.0332, respectively. UPGMA dendrogram based on the 'Nei's (Genetics 89: 583-590, ) genetic distance method' showed greater genetic distance of Darjeeling population from Terai as compared to Dooars populations. [ABSTRACT FROM AUTHOR]

Climate change, deforestation and over reliance on chemical pesticides during the last five decades are presumed to have had a significant impact on the incidence and abundance of agricultural pests . The thrips ( Scirtothrips dorsalis Hood) and the greenfly ( Empoasca flavescens Fabricius), which were previously considered as minor or occasionally as serious pests in localized areas of tea plantations, are now established as regular and at times major pests in tea plantations of North Bengal spread over the sub Himalayan slopes and the adjoining plains of Terai and the Dooars. Tea-planters from different pockets of North Bengal have been repeatedly reporting control failures of these pests with the use of insecticides in recommended dilutions. A study of their seasonal incidence along with activity of detoxifying enzymes was considered. The trend of a recent population study revealed that E. flavescens and S. dorsalis were abundant throughout the year, with peaks during April to June. Abiotic factors such as temperature, rainfall, sunshine hours and relative humidity (afternoon) influenced the population abundance. Insecticide-exposed populations showed higher levels of activity of the detoxifying enzymes than those collected from organic plantations and the laboratory-reared populations that had not been exposed to insecticides. Detoxifying enzymes in insecticide-exposed E. flavescens collected from Terai and the Dooars as compared with laboratory control specimens showed 3.0-5.2 and 3.0-9.7-fold increases in general esterases (GEs), 1.5-4.8 and 3.6-5.3-fold increases in cytochrome P450s (CYPs) and 1.2-3.5 and 1.5-2.5-fold increases in glutathione-s-transferases (GSTs), respectively. Similarly, S. dorsalis collected from Terai and the Dooars showed 2.0-6.0 and 2.3-5.6-fold increases in GEs, 1.5-2.3 and 1.6-2.4-fold increases in CYPs and 2.6-3.7 and 2.3-3.6-fold increases for GSTs, respectively. Bands of isozymes of esterase I-VI and I-V were found to be expressed in insecticide-exposed specimens whereas a negligible expression was evident for the bands in unexposed E. flavescens and S. dorsalis of organic plantations and laboratory-reared origins, respectively. The data obtained in the present study would be useful in developing the integrated resistance management strategies leading to effective management of the said pests. [ABSTRACT FROM AUTHOR]