White-backed Planthopper Research Articles

Screening of the highly pathogenic Beauveria bassiana BEdy1 against Sogatella furcifera and exploration of its infection mode.

The white-backed planthopper (WBPH, Sogatella furcifera) is a notorious pest affecting rice production in many Asian countries. Beauveria bassiana, as the most extensively studied and applied insect pathogenic fungus, is a type of green and safe biological control fungus compared to chemical insecticides, and it does not pose the "3R" problem. In this study, the strain BEdy1, which had better pathogenicity to WBPH, was screened out from eight strains of B. bassiana. The daily growth rate, sporulation, and germination rate of BEdy1 strain were 3.74 mm/d, 1.37 × 108 spores/cm2, and 96.00%, respectively, which were significantly better than those of other strains. At a concentration of 1 × 108 spores/mL, the BEdy1 strain exhibited the smallest LT50 value (5.12 d) against the WBPH, and it caused the highest cumulative mortality and muscardine cadaver rates of the pest, which were 77.67 and 57.78%, respectively. Additionally, BEdy1 exhibited a significant time-dose effect on WBPH. This study further investigated the pathogenic process of BEdy1. The results showed that BEdy1 invaded by penetrating the body wall of the WBPH, with its spores mostly distributed in the insect's abdominal gland pores, compound eyes on the head, and other locations. At 36 h, the germinated hyphae penetrated the insect's body wall and entered the body cavity. At 84 h, the hyphae emerged from the body wall and accumulated in the insect's abdomen, leading to a significant number of insect deaths at this stage. At 120 h, the hyphae entangled the insect's compound eyes and produced new conidia on the insect's body wall, entering a new cycle of infection. These findings indicate that BEdy1 has a strong infection ability against WBPH. In summary, this study provides a new highly pathogenic strain of B. bassiana, BEdy1, for the biological control of WBPH, which is of great significance for the green prevention and control of rice pests.

Structural characterization and proteomic profiling of oviposition secretions across three rice planthopper species

Insect oviposition secretions play crucial roles during the reproductive process, yet systematic studies on their structural characterization and protein compositions remain limited. This study investigated the oviposition secretions of three major rice pests: the brown planthopper (Nilaparvata lugens, BPH), small brown planthopper (Laodelphax striatella, SBPH), and white-backed planthopper (Sogatella furcifera, WBPH). Ultrastructural observation revealed differences in the oviposition secretions of them. The eggs of BPH and SBPH were adhered to rice tissue by abundant secretions, while WBPH eggs were embedded deeper within the leaf sheath with less secretions. Proteomic analysis identified 111, 98, and 66 oviposition secretion proteins (OSPs) in BPH, SBPH, and WBPH, respectively. 4 common protein subgroups were shared among them, along with varying numbers of shared subgroups between species pairs. Notably, the majority of OSPs were exclusively found in one species, indicating the existence of both similar and specialized functions unique to each planthopper species. The functions of 4 uncharacterized OSPs (Nl.chr07.0363, Nl.chr12.078, Nl.chr11.716, Nl.scaffold.0714) that were uniquely identified in the BPH were studied by maternal RNAi. Downregulation of each of these 4 protein-coding genes led to a significant decrease in egg production and hatchability. Moreover, knockdown of Nl.chr12.078 or Nl.chr07.0363 also disrupt the secretory function of the lateral oviduct. In conclusion, this study provides insights into the structural characteristics and protein components of the oviposition secretions of BPH, SBPH, and WBPH, which could serve as potential targets for RNAi-based pest control and lay a foundation for future studies on insect-plant interactions mediated by oviposition secretions.

Augmenting Rice Defenses: Exogenous Calcium Elevates GABA Levels Against WBPH Infestation.

This study investigates the impact of exogenous calcium and gamma-aminobutyric acid (GABA) supplementation on rice growth and stress tolerance under white-backed planthopper (WBPH) infestation. We evaluated several phenotypic traits, including shoot/root length, leaf width, tiller number, panicle length, and relative water content, alongside physiological markers such as oxidative stress indicators, antioxidant enzymes activities, hormonal levels, and amino acids biosynthesis. Our results indicate that WBPH stress significantly reduces growth parameters but calcium and GABA supplementation markedly enhance shoot length (by 26% and 36%) and root length (by 38% and 64%), respectively, compared to WBPH-infested plants. Both supplementations also reduced oxidative stress, as evidenced by decreased H2O2 and O2•- levels and a lower electrolyte leakage. Notably, calcium and GABA treatments increased antioxidant enzyme activities, with GABA boosting catalase (CAT) activity by 800%, peroxidase (POD) by 144%, and superoxide dismutase (SOD) by 62% under WBPH stress. Additionally, calcium and GABA enhanced the accumulation of stress hormones (abscisic acid ABA) and salicylic acid (SA) and promoted stomatal closure, contributing to improved water conservation. This study reveals that calcium regulates the GABA shunt pathway, significantly increasing GABA and succinate levels in both root and shoot. Furthermore, calcium and GABA supplementation enhance the biosynthesis of key amino acids and improve ion homeostasis, particularly elevating calcium (Ca), iron (Fe), and magnesium (Mg) levels under WBPH stress. Overall, this study highlights the potential of exogenous calcium and GABA as effective strategies for enhancing rice plant tolerance to WBPH infestation by modulating various physiological and biochemical mechanisms. Further research is warranted to fully elucidate the underlying mechanisms of action.

Crucial role of a takeout protein in white-backed planthopper Sogatella furcifera (Horváth) orientation towards its host rice plants.

The takeout (TO) gene family impacts diverse physiological and behavioral functions in insects, yet specific olfactory-associated roles for the family have yet to be fully elucidated. To provide insights into TO function in rice planthoppers, the genomes of three rice planthoppers (white-backed planthopper, brown planthopper and small brown planthopper) were searched for TO homologs and their degree of conservation assessed via chromosomal localization, exon-intron boundaries, phylogenetic relationships and protein domains/motifs. We performed a tissue-specific expression analysis of the 20 TO genes in the white-backed planthopper (WBPH, Sogatella furcifera) and found that SfTO17 is enriched in adult antennae. RNAi-mediated knockdown of SfTO17 impaired WBPH olfaction and reduced host-seeking responses following exposure to rice plants. The binding profile of β-ionone, hexyl benzoate and benzyl benzoate with recombinant SfTO17 was evaluated via competitive fluorescence binding assays. Conformational prediction of SfTO17 coupled with molecular docking analyses revealed several amino acid residues potentially critical for odorant binding. This study demonstrates the olfactory function of SfTO17 in WBPH and highlights its potential as a target for controlling this rice pest. © 2024 Society of Chemical Industry.

An investigation into the biology and lifetable characteristics of white backed plant hopper, Sogatella furcifera (Horvath) in paddy field

An investigation into the biology and lifetable characteristics of white backed plant hopper, Sogatella furcifera (Horvath) in paddy field

Identification and knockout of a herbivore susceptibility gene enhances planthopper resistance and increases rice yield.

Brown planthoppers (Nilaparvata lugens) and white-backed planthoppers (Sogatella furcifera) are among the most destructive pests on rice. However, plant susceptibility genes have not yet been exploited for crop protection. Here we identified a leucine-rich repeat protein, OsLRR2, from susceptible rice varieties that facilitates infestation by brown planthopper N. lugens. Field trials showed that knockout of OsLRR2 significantly reduced BPH infestation and enhanced natural biological control by attracting natural enemies. Yield of a susceptible variety was increased by 18% in insecticide-treated plots that eliminated planthoppers and by 25% in untreated plots. These findings underscore the pivotal role of OsLRR2, offering a promising pathway for pest population suppression and rice yield increase.

Seasonal variations of insect abundance: Correlating growth stage-specific metrics with weather patterns in Rangpur Region, Bangladesh

The disclosure of insect occurrences correlating with meteorological data is pivotal in devising effective management strategies for rice fields. The study collected data on harmful and beneficial insects, along with meteorological variables, for three consecutive rice-growing seasons in 2021 and 2022. Month-wise insect distribution were delineated, with prominent species such as green leafhopper, brown planthopper, white-backed planthopper, rice whorl maggot, damselfly, parasitic wasps and green mirid bug observed consistently. Notably, most of the harmful insects were predominantly present during March–July and September–October. The spatial distribution, further segmented based on the rice-growing seasons, revealing the Aus season's preeminence in hosting harmful insects followed by Aman and Boro. The prevalence of most of the harmful insects were in tillering stage. Beneficial insects, displayed their dominance during specific months, growth stage, emphasizing their potential role in controlling harmful species and their prevalence were increased by increased of harmful insects. Furthermore, the study elucidated the correlation between climatic factors and insect abundance, emphasizing the role of temperature, rainfall and relative humidity. Temperature metrics and relative humidity manifested significant associations with several insects both harmful and beneficial species differently. While rainfall notably correlated with rice bug, short-horned grasshoppers, yellow stem borer, and non-significant association with other insects. The study underscored mutual dependencies between predator and prey species, emphasizing the ecological balance within the agricultural ecosystem. This comprehensive analysis indicated the need for integrated pest management strategies, considering both harmful and beneficial insect dynamics, to promote sustainable practices for optimizing rice production in changing climatic scenarios.

Phytoplasma Associated with White-backed Planthopper on Rice Plants in Sidrap Regency, South Sulawesi

South Sulawesi is one of the largest rice production centers in Indonesia. Several important diseases of rice plants, such as those caused by viruses and phytoplasmas, can be transmitted by insect vectors, especially leafhoppers and stem plant. Symptoms of diseases caused by viruses and phytoplasmas are quite diverse but visually similar and difficult to distinguish. This study aims to analyze the presence of phytoplasma associated with white-backed planthopper which are commonly found in rice plantations. The research method used is by conducting surveys and explorations of insect samples in six villages in Sidrap District. White-back planthoppers found on rice plantations showing symptoms of yellowing and stunted leaves were sampled for further analysis, including total DNA isolation of insects, standard PCR amplification for insect and Nested-PCR for phytoplasma identification, gene sequencing for both amplicons, and nucleotide analysis using BLAST method and Mega X program. The PCR with CO1 primer successfully amplified a 700 bp amplicon from insects, whereas nested-PCR using fP1/rP7 primers followed by m23SR/R16F2n amplified phytoplasma supposedly around 1800 bp and 1250 bp of 16S RNA gene, respectively. The DNA sequencing analysis results indicate that the insect samples were identified as 83% Sogatella vibix species based on homology percentage analysis using BLAST and Mega X Program. As for the phytoplasma, it leans more towards the 16SrI group or Candidatus phytoplasma asteris (Aster yellows phytoplasma) with a homology percentage of 99%.

THE EFFECT OF ZINC ON WHITE-BACKED PLANTHOPPER INFESTATION, RICE PLANT BIOCHEMICAL RESPONSES CROP YIELD, AND INSIGHTS FOR SUSTAINABLE PEST MANAGEMENT

The white-backed planthopper (WBPH), Sogatella furcifera, has emerged as a highly destructive rice crop pest, leading to significant annual yield losses. Excessive zinc (Zn) can be detrimental to plants, but the role of Zn on herbivorous insects remains uncertain. In this research, we conducted a pot culture experiment in the Kharif season 2017 at the Department of Entomology, College of Agriculture, OUAT, Bhubaneswar, Odisha, India. The aim was to investigate the effect of Zn (in the form of Zn EDTA or ZnSO4) when applied as a basal or foliar spray, either alone or in various combinations, on the WBPH. Our findings revealed that the population of WBPH in the control group of rice plants was at its highest (79.20) at 60 days after transplanting (DAT) compared to the groups treated with Zn. Further, an analysis of 60-day-old plant samples showed that applying Zn increased levels of chlorophyll, phenols, and soluble protein content. In addition, there was an elevation in the activity of superoxide dismutase (SOD), peroxidase (POD), and phenylalanine ammonia-lyase (PAL). Simultaneously, this treatment decreased the levels of total free amino acids, total soluble sugars, and proline content. Both increase and decrease in respective biochemical parameters were indicators of an induced antibiosis mechanism in rice plants against the WBPH. The correlation analysis between the WBPH population and various plant biochemical parameters showed that the WBPH population was inversely correlated with total chlorophyll, phenol, soluble protein content, as well as the activities of SOD, POD, and PAL. Conversely, it positively correlated with total free amino acids, soluble sugars, and proline content. Therefore, this research has provided valuable insights into the presence of Zn, which significantly influences the population of WBPH, suggesting a potential avenue for WBPH control and rice yield improvement through strategic Zn application.. KEYWORDS :Antibiosis, Biochemical parameters, Enzymes, Rice, Zinc

Effective multidimensional treatment identification of different chemical fertilizers: Response of insect dynamics and rice production

Effective management of fertilizers is essential in influencing the prevalence of insects in rice (Oryza sativa L.) fields. Over two years (2019-20 and 2020-21), an experiment conducted at Bangladesh Rice Research Institute (BRRI), Habiganj, during the boro season aimed to identify the most effective multidimensional treatment (EMT) by testing various combinations of chemical fertilizers and its effect on rice insects. The goal was to optimize rice grain yield while minimizing harmful insect infestation and supporting natural enemies. Eight different chemical fertilizer applications were used as follows: T1 contained a full mix of nitrogen (N), phosphorus (P), potassium (K), and sulfur (S); T2 had PKS but lacked N; T3 had NKS but lacked P; T4 had NPS but lacked K; T5 had NPK but lacked S; T6 had KS but lacked N and P; T7 had PS but lacked N and K; and T8 lacked all four elements - N, P, K, and S.The relationship between the dynamics of harmful insects and natural enemies was highly positively correlated (r = 0.72 to 0.97). In two consecutive growing years, the 2020-21 season exhibited notably higher counts of harmful insects, with Rice Leafroller (RLR) dominating in the booting stage and White Backed Planthopper (WBPH) in mid-tillering, while Green Mirid Bug (GMB) prevailed among natural enemies across both stages, surpassing insect pest counts, notably GMB, Lady bird beetle (LBB), Carabid beetle (CDB), and Staphylinid (STD). However, the yield was notably higher in the 2019-20 growing season despite these pest pressures. Throughout the mid-tillering and booting stages, T1 consistently exhibited the highest average populations of harmful insects and natural enemies, while T7 demonstrated the lowest count of harmful insects, followed by T2 at both growth stages. Additionally, the highest grain yield (GY) was consistently recorded in T1, followed by T5, T6, and T3, with yields of 7.98 t/ha, 7.63 t/ha, 7.38 t/ha, and 7.33 t/ha, respectively. In both stages, beneficial insects prevailed over harmful ones in all fertilizer applications, with significant declines noted in T2 and T7. Factor analysis showed successful selection for EMT in the MGIDI index for all variables except INT and GY during the 2019-20 season, with selection differentials (SD) ranging from −0.10 to 8.29. However, in 2020-21, selection was achieved for all variables with SD ranging from 0.37 to 6.08. According to the MGIDI index, the top-ranked EMTs were identified as T4 and T3 for the 2019-20 period, and T3 and T5 for the 2020-21 period. The EMT shared in both years, T3, proved effective because of its positive impact on enhancing natural enemies throughout both periods (with SD ranging from 4.76 to 8.29 for 2019-20 and 3.03 to 6.08 for 2020-21), and its notable contribution to rice grain yield (SD = 0.37) in 2020-21. This study uniquely integrates EMT to optimize rice grain yield while simultaneously managing harmful insect infestations and supporting natural enemies, addressing a critical need in sustainable rice cultivation. The suggestion is to give preference to fertilizer application T3, which omits P but contains N and K, to improve rice grain yield and boost natural enemies, thereby reducing harmful insect infestation. Moreover, future investigations should concentrate on refining fertilizer blends to strike a harmony between maximizing yield and fostering ecological robustness in rice cultivation.

Identification and Characterization of Three Novel Solemo-like Viruses in the White-Backed Planthopper, Sogatella furcifera.

Agricultural insects play a crucial role in transmitting plant viruses and host a considerable number of insect-specific viruses (ISVs). Among these insects, the white-backed planthoppers (WBPH; Sogatella furcifera, Hemiptera: Delphacidae) are noteworthy rice pests and are responsible for disseminating the southern rice black-streaked dwarf virus (SRBSDV), a significant rice virus. In this study, we analyzed WBPH transcriptome data from public sources and identified three novel viruses. These newly discovered viruses belong to the plant-associated viral family Solemoviridae and were tentatively named Sogatella furcifera solemo-like virus 1-3 (SFSolV1-3). Among them, SFSolV1 exhibited a prevalent existence in different laboratory populations, and its complete genome sequence was obtained using rapid amplification of cDNA ends (RACE) approaches. To investigate the antiviral RNA interference (RNAi) response in WBPH, we conducted an analysis of virus-derived small interfering RNAs (vsiRNAs). The vsiRNAs of SFSolV1 and -2 exhibited typical patterns associated with the host's siRNA-mediated antiviral immunity, with a preference for 21- and 22-nt vsiRNAs derived equally from both the sense and antisense genomic strands. Furthermore, we examined SFSolV1 infection and distribution in WBPH, revealing a significantly higher viral load of SFSolV1 in nymphs' hemolymph compared to other tissues. Additionally, in adult insects, SFSolV1 exhibited higher abundance in male adults than in female adults.

THE EFFECT OF SOAKING DURATION OF TUBA ROOTS (Derris elliptica) ON THE MORTALITY OF THE WHITE-BACKED PLANTHOPPER PESTS (Metcalfa pruinosa)

Tuba root (Derris elliptica) is a plant that contains rotenone in roots where this content functions as a poison for insects, so tuba root has the opportunity to be used as a vegetable pesticide in pest control activities. Research on tuba roots as control of white-backed planthopper pests (Metcalfa pruinosa) on green deli water guava plants (Syzygium aqueum L.) has never been carried out, therefore research was conducted which aimed to determine the effect of long soaking of tuba roots (Derris elliptica) on the death of planthopper pests white back (Metcalfa pruinosa) on green deli water guava (Syzygium aqueum L.). The type of research used was experimental research using 5 treatments, namely soaking tuba roots for 12, 24, 36 and 48 hours. The data analysis technique uses the one way ANOVA test and the BNT test at the 0.05 level. The results of the one-way ANOVA test data analysis produced a significant value of less than 0.05, so it can be concluded that the length of soaking tuba roots influences the death rate of white-backed planthopper pests. The treatment that has the most influence on the death of white-backed planthopper pests is application three times a week using tuba root soaking for 12 hours with a mortality rate of 36%.

Tip60 complex regulates eggshell formation and oviposition in the white-backed planthopper, providing effective targets for pest control

Tip60 complex regulates eggshell formation and oviposition in the white-backed planthopper, providing effective targets for pest control

Nanoparticle-delivered RNAi-based pesticide target screening for the rice pest white-backed planthopper and risk assessment for a natural predator

Vacuolar-type (H+)-ATPase (vATPase) is a conserved multi-subunit eukaryotic enzyme composed of 14 subunits that form a functional complex consisting of an ATP-hydrolytic domain (V1) and a proton-translocation domain (V0). ATP hydrolysis and subsequent H+ translocation rely heavily on a fully assembled V1/V0 complex. Since vATPase is crucial for insect survival, it is a viable molecular target for pest control. However, detailed functional analyses of the 14 subunits and their suitability for pest control have not been fully explored in a single insect species. In this study, we identified 22 vATPase subunit transcripts that correspond to 13 subunits (A1, A2, B, C, D, E, F, G, H, a1, a2, c and d) in the white-backed planthopper (WBPH), Sogatella furcifera, a major hemipteran pest of rice. RNAi screens using microinjection and spray-based methods revealed that the SfVHA-F, SfVHA-a2 and SfVHA-c2 subunits are critical. Furthermore, star polymer (SPc) nanoparticles were utilized to conduct spray-induced and nanoparticle-delivered gene silencing (SI-NDGS) to evaluate the pest control efficacy of RNAi targeting the SfVHA-F, SfVHA-a2 and SfVHA-c2 transcripts. Target mRNA levels and vATPase enzymatic activity were both reduced. Honeydew excreta was likewise reduced in WBPH treated with dsRNAs targeting SfVHA-F, SfVHA-a2 and SfVHA-c2. To assess the environmental safety of the nanoparticle-wrapped dsRNAs, Cyrtorhinus lividipennis Reuter, a major natural enemy of planthoppers, was also sprayed with dsRNAs targeting SfVHA-F, SfVHA-a2 and SfVHA-c2. Post-spray effects of dsSfVHA-a2 and dsSfVHA-c2 on C. lividipennis were innocuous. This study identifies SfVHA-a2 and SfVHA-c2 as promising targets for biorational control of WBPH and lays the foundation for developing environment-friendly RNAi biopesticides.

Heterosis for Resistance to Insect Herbivores in a 3-Line Hybrid Rice System.

Three-line hybrid rice is produced by crossing male sterile (A line) rice with a fertility-restorer (R line). Fertile lines (B lines) are also required to maintain A line seed for breeding programs. We used a range of hybrids and their parental lines to assess the frequency and nature of heterosis for resistance to the whitebacked planthopper (Sogatella furcifera), brown planthopper (Nilaparvata lugens) and yellow stemborer (Scirpophaga incertulas). Heterosis is defined as trait improvement above the average of the parental lines as a result of outbreeding. Based on the results from a greenhouse study that challenged hybrids and their parental lines with each herbivore species, we found that susceptibility to planthoppers was associated with one of the eight A lines tested, but resistance was improved by crossing with a relatively resistant restorer. Higher frequencies of heterosis for susceptibility in comparisons between hybrids and their B lines suggest that susceptibility was not related to the cytoplasmic genomes of the associated sterile A lines. Furthermore, because none of the parental lines possessed currently effective resistance genes, improved resistance against planthoppers was probably due to quantitative resistance. In a related field trial, hybrids had generally higher yields than their fertile parents and often produced larger grain; however, they were often more susceptible to stemborers, leaffolders (Cnaphalocrocis medinalis) and other caterpillars (Rivula atimeta). This was largely a consequence of hybrid heterosis for plant biomass and was strongly affected by crop duration. We make a series of recommendations to improve hybrid breeding to reduce the risks of herbivore damage.

Rainfall during the night can trigger non-migratory take-off behavior of the white-backed planthopper, Sogatella furcifera.

Take-off behavior is crucial to the overall success of insect migration. Although most high-altitude migratory flights commence with mass take-offs around dusk and dawn, little is known about nighttime take-off behavior. The take-off behavior of migratory Sogatella furcifera was investigated in field cages from 2017 to 2019. The species showed a bimodal take-off pattern at dusk and dawn on rainless nights, with mass flight at dusk more intense than dawn flight. However, a higher frequency of take-offs during the nighttime was observed on rainy nights, resulting in the absence of dawn take-offs. Most migratory take-off individuals at dusk and dawn landed on the cage top or the walls above 150cm, while non-migratory individuals that took off during the nighttime due to rainfall mainly landed on the cage walls below 150cm. Furthermore, it has been observed that migratory take-off individuals possess stronger sustained flight capabilities and exhibit more immature ovaries compared with non-migratory take-offs. These findings advance our understanding of the take-off behavior of S. furcifera and thus provide a basis for the accurate prediction and management of the migratory dynamics of this pest.

Insecticidal activity against rice pest of oxazosulfyl, a novel sulfyl insecticide.

The development and commercialization of new chemical classes of insecticides are important for efficient crop protection, particularly for combatting insecticide resistance and providing sustainable agricultural production. This study reports on oxazosulfyl, a novel "sulfyl" class of insecticide, against a wide range of insect pests of rice. In the laboratory assay, oxazosulfyl showed insecticidal activity against all developmental stages of the brown planthopper Nilaparvata lugens (Stål). Phosphor imaging assays and soil drench bioassays demonstrated good systemic distribution in rice plants. Oxazosulfyl showed insecticidal activity against imidacloprid- and fipronil-resistant field populations of N. lugens, the white-backed planthopper Sogatella furcifera (Horváth), and the small brown planthopper Laodelphax striatellus (Fallén), as well as the respective susceptible strains. No cross-resistance was observed among oxazosulfyl, imidacloprid, and fipronil. Oxazosulfyl with a wide insecticidal spectrum is a potentially useful pest management tool for sustainable rice production.

Efficacy of Some Insecticides in Combination with Neem on Rice Planthoppers

A field experiment was carried out during kharif 2020, at the Agricultural College Farm, Bapatla to evaluate the efficacy of some insecticides in combination with neem against rice planthoppers in direct seeded rice crop. The results showed that triflumezopyrim 10.6SC @ 25g a.i. ha-1 was the most effective treatment against both brown planthopper Nilaparvata lugens (Stål) and white backed planthopper Sogatella furcifera (Horváth) with 73.61 and 77.69% reductions over untreated control, respectively at 5 DAT. The other effective treatments were dinotefuran 20SG @ 40 g a.i. ha-1 and pymetrozine 50WG @ 150 g a.i. ha-1 with 70.14 and 66.44% reduction of N. lugens and 71.89 and 69.66% reduction of S. furcifera, respectively over untreated control at 5 DAT. Neem formulation 1500 ppm revealed the lowest efficacy with 34.95 and 36.19% reduction of N. lugens and S. furcifera over the untreated control at 5 DAT.

Phylogeographic structure and putative migration pathway of Sogatella furcifera in China based on microsatellite markers

AbstractThe white back planthopper (WBPH), Sogatella furcifera (Horváth) (Hemiptera: Delphacidae), is an important destructive rice pest in Asia that has caused serious economic losses in the main rice‐producing areas of China. To effectively manage this rice pest, it is necessary to investigate its genetic variation and genetic structure and speculate the migration route in China. In this study, we used 12 nuclear microsatellite loci to analyse the genetic variation, gene flow and genetic structure of WBPH in 25 geographic populations in China. Overall, high levels of genetic diversity and genetic differentiation among most populations were detected. Neighbour‐joining dendrograms, STRUCTURE and principal coordinate analysis (PCoA) revealed three genetically distinct groups and exhibited an admixed phylogeographic structure. There was a significant low positive correlation between genetic and geographic distances (r2 = 0.105, p = 0.001), which indicated the role of geographic isolation in the genetic structure of WBPH. Migrant routes detection indicated frequent gene flow exchange between North China and Central China, and low bidirectional gene flows between Northeast China and other regions were detected. Accordingly, this study provides useful data for resolving the genetic relationships and large‐scale migration route of the WBPH and thus contributes to developing more effective management strategies for controlling this pest.

RNA Interference-Screening of Potentially Lethal Gene Targets in the White-Backed Planthopper Sogatella furcifera via a Spray-Induced and Nanocarrier-Delivered Gene Silencing System.

RNA interference (RNAi) is a widespread post-transcriptional silencing mechanism that targets homologous mRNA sequences for specific degradation. An RNAi-based pest management strategy is target-specific and considered a sustainable biopesticide. However, the specific genes targeted and the efficiency of the delivery methods can vary widely across species. In this study, a spray-induced and nanocarrier-delivered gene silencing (SI-NDGS) system that incorporated gene-specific dsRNAs targeting conserved genes was used to evaluate phenotypic effects in white-backed planthopper (WBPH). At 2 days postspraying, transcript levels for all target genes were significantly reduced and knockdown of two gene orthologs, hsc70-3 and PP-α, resulted in an elevated mortality (>60%) and impaired ecdysis. These results highlight the utility of the SI-NDGS system for identifying genes involved in WBPH growth and development that could be potentially exploitable as high mortality target genes to develop an alternative method for WBPH control.