Orosius Orientalis Research Articles

An introductory review on the common brown leafhopper (Orosius orientalis): A new soybean pest

Soybean pests are one of the major factors limiting yield improvement. With the expansion of area and changes in cropping patterns, a number of new pests have been identified in the main soybean production areas of China. The common brown leafhopper, Orosius orientalis, is a new pest associated with soybean stay-green virus that has been discovered on cultivated soybean crop in the Yellow-Huai-hai region of China in recent years. The polyphagous insect has a wide feeding range and infests a variety of important grain and cash crops. This paper presents the basic information, geographical distribution, hosts, damage characteristics, plant virus transmission, occurrence patterns, and prevention and control measures O. orientalis. This review also provides insights into integrated prevention and control of the genus Orosius as an insect vector.

Determination of Population Dynamics of Cicadellidae (Hemiptera) Species and Their Relationship with Climatic Parameters in Organic Cotton Fields in Hatay Province, Türkiye

In this study, population dynamics of leafhopper (Hemiptera: Cicadellidae) species in organic cotton-growing areas of Hatay province were investigated along with their associations with climatic parameters. Weekly sampling using a sweep net (100 sweep net/parcel) identified nine species within the Cicadellidae family. Among these, Asymmetrasca decedens (Paoli) and Empoasca decipiens (Paoli) displayed high population densities throughout the entire vegetation period of cotton, while Zyginidia sohrab (Zatchvakin), Psammotettix striatus (Linnaeus), Orosius orientalis (Matsumura), Anaceratagallia laevis (Ribaut), and Anaceratagallia sinuata (Mulsant & Rey) were present in both vegetative and reproductive phases of cotton, with Z. sohrab reaching significant population levels. Cicadulina bipunctella (Matsumura) and Balclutha hebe (Kirkaldy) were found only during the reproductive phase, yet they achieved considerably high populations. Correlation and regression analyses have shown a moderate to high level of positive correlation between the population development of five leafhopper species and various temperature (°C) parameters (r=0.578-0.790, p

Epidemiological evaluation and identification of the insect vector of soybean stay-green associated virus

In recent years, the emergence of soybean stay-green syndrome (SGS), also referred to as ‘zhengqing’, in the Huang-Huai-Hai region of China has resulted in significant yield losses. SGS is a phenomenon characterized by the delayed senescence of soybean, resulting in stay-green leaves, flat pods, and stunted seed development at harvest. We previously identified a distinct geminivirus, named soybean stay-green associated geminivirus (SoSGV), as the causative agent of SGS by fulfilling Koch’s postulates. To further understand the epidemiology of SoSGV, in this study, we collected 368 stay-green samples from 17 regions in 8 provinces including the Huang-Huai-Hai region and surrounding areas. The results showed that 228 samples tested positive for SoSGV (61.96%), and 96.93% of these positive samples showed severe pod deflation. Our epidemiological assessment reveals that SGS caused by the SoSGV is prevalent in the fields, and it is undergoing geographical expansion and genetic differentiation. Additionally, we determined other natural hosts grown in the Huang-Huai-Hai region. By capturing insects in the field and conducting laboratory vector transmission tests, we confirmed that the common brown leafhopper (Orosius orientalis) is the transmission vector of SoSGV. With a better understanding of the transmission and epidemiology of SoSGV, we can develop more effective strategies for managing and mitigating its impact on soybean yields.

Leafhopper transmits soybean stay-green associated virus to leguminous plants

A novel geminivirus, soybean stay-green associated virus (SoSGV), was previously shown to cause soybean delayed senescence and is associated with the incidence of soybean stay-green syndrome. The modes of SoSGV transmission were not yet known. We captured insects belonging to 24 distinct species in a soybean field with the SoSGV outbreak and detected the presence of SoSGV only in leafhoppers and bean bugs (Riptortus pedestris). Caged feeding experiments using captured leafhoppers and bean bugs from soybean fields showed that leafhoppers, but not bean bugs, are vectors transmitting SoSGV. The common brown leafhopper (Orosius orientalis) is identified as the dominant leafhopper species and can establish colonies feeding on soybean plants in experimental conditions. An investigation of SoSGV defective DNA revealed that soybean genomic DNA fragments could be inserted into the SoSGV genome, while sequences from wild soybean, red bean, and cowpea were also identified. We further showed that the common brown leafhopper could transmit SoSGV to wild soybean and red bean plants, emphasizing a vector’s role of the leafhopper in the transmission of SoSGV in the field.

Abundance and Population Dynamics of the Key Insect Pests and Agronomic Traits of Tomato (Solanum lycopersicon L.) Varieties under Different Planting Densities as a Sustainable Pest Control Method

In Saudi Arabia, the tomato is susceptible to a wide range of insect pests that could destroy this valuable vegetable crop, cause yield losses, and affect fruit quality and quantity. Insecticides are widely applied to protect tomatoes and control pests that develop a resistance to pesticides, but these affect human health and have a negative impact on the environment. The application of Good Agriculture Practices (GAP) is a worthwhile sustainable alternative for controlling insect pests in tomato fields. To investigate the population dynamics of the major pests affecting tomato growth and yield, two commercial varieties (Areenez F1 and Tala F1) were cultivated at three plant spacings (30 × 50 cm, 60 × 50 cm, and 90 × 50 cm) under the conditions of the desert climate. The experiments were conducted in the field in 2020 and 2021 and were laid out in a Randomized Complete Block Design (RCBD) with each treatment repeated for 4 times. A total of 14 major insect pests including Empoasca fabae, Bemisia tabaci, Orosius orientalis, Acheta domesticus, and Lasius niger were recorded on a weekly basis. The results showed that the mean abundances of E. fabae, O. orientalis, and B. tabaci were higher in the 30 × 50 cm plant spacing, whereas the 90 × 50 cm plant spacing resulted in a higher abundance of A. domesticus and L. niger. The measured agronomic traits, plant height (cm), plant dry mass (g), and total yield/ha (ton) of both the tomato varieties were significantly increased when the plants were spaced at 60 cm between plants and 50 cm between rows. We recommend that growing tomato plants at 60 cm between plants and 50 cm between rows may reduce the need to apply pesticides given that this plant spacing significantly reduced the abundance of some key insect pests and enhanced the tomato fruit yield.

Phytoplasmas of sesame and Orosius orientalis are genetically diverse based on 16S rDNA sequencing and PCR-RFLP in Turkey

Sesame phyllody causes significant yield losses mainly in Mediterranean region of Turkey. To detect and identify phytoplasmas of sesame and the cicadellid vector Orosius orientalis, samples were collected during 2011–2013 in Antalya. Nested PCR amplification of the 16S rDNA gave an amplification band of approximately 1246 bp corresponding to the 16Sr F2nR2 region. Identification of the phytoplasmas based on sequence homology revealed presence of the 16Sr groups II (Peanut witches’-broom, PnWB), VI (Clover proliferation, CP) and IX (Pigeon pea witches’-broom, PPWB) in sesame plants. PnWB and CP were detected in O. orientalis. Subgroups were determined by sequencing and PCR-RFLP of the F2nR2 region. 16Sr subgroups II-D, VI-A and IX-C were identified from sesame and II-D and VI-A subgroups from the insect vector. This study shows that phytoplasmas in sesame and O. orientalis are genetically diverse and to the knowledge, VI-A group phytoplasmas from sesame and O. orientalis were characterised molecularly for the first time in Turkey.

A revision of the genusOrosiusDistant (Hemiptera: Cicadellidae) based on male genitalia and DNA barcoding

AbstractA morphological and molecular review of the genusOrosiusDistant (Deltocephalinae: Opsiini) was undertaken using male genitalia and DNA barcoding. We recognise 14 valid species of the genus, of which two were indeterminate, based on females only and recognised only by DNA barcodes.Orosius argentatus(Evans) stat. rev. is removed from synonymy withOrosius orientalis(Matsumura) after DNA barcoding demonstrated that the two species are distinct; small but consistent differences in the male genitalia are also found to support the two species hypothesis. The other species, recognised on male genitalia, are confirmed with DNA barcode sequence data. These species areOrosius albicinctusDistant,Orosius lotophagorum(Kirkaldy),Orosius canberrensis(Evans),Orosius ryukyuensis(Ishihara) andOrosius cellulosus(Lindberg), plus five new species described herein asOrosius albifronsFletcher & Löcker sp. nov. andOrosius brunneusFletcher & Löcker sp. nov. from Barrow Island, Western Australia,Orosius recurvusFletcher & Löcker sp. nov. from New South Wales andOrosius magareyiFletcher & Löcker sp. nov. andOrosius pallidusFletcher & Löcker sp. nov. from Loxton, South Australia. This is the first record ofO. cellulosusfrom Australia.Orosius aegypticusGhauri syn. nov. is synonymised withO. albicinctus, the synonymy ofNesaloha cantonisOman syn. nov. is transferred toO. orientalisfromO. argentatusandOrosius argentatus novaebrittaniaeGhauri syn. nov. is synonymised withO. orientalis. Orosius minuicusDlabola is excluded from the genus. A key for the discrimination and identification of the species based on male genitalia is provided.

Sapu pada Kacang Hias (Arachis pintoi): Penyakit Baru yang Berasosiasi dengan Fitoplasma

Pinto peanut ( Arachis pintoi ) witches’ broom is a new disease found in Bogor at high incidence and has not yet been reported elsewhere. Symptom type of the disease is very similar to that of peanut ( A. hypogea ) witches’ broom, which has been well known to be associated with phytoplasma. Both A. pintoi and A. hypogea witches’ broom causal agent are transmissible to both healthy A. pintoi or A. hypogea , with grafting or vector transmission using peanut witches’ broom phytoplasma specific vector, Orosius argentatus . All combination of transmission means resulted in an identical type of witches’ broom symptom. Further confirmation using polymerase chain reaction detection and identification of phytoplasma employing universal primer pair for phytoplasmas (P1/P7), showed that all of the diseased plants, either from field or transmitted plants is associated with phytoplasma. The A. pintoi witches’ broom phytoplasma is likely identical to that of A. hypogea. Key words: Arachis pintoi, Orosius argentatus , phytoplasma, witches’ broom

Overview on a century progress in research on sesame phyllody disease

Sesame is the most ancient oil seed plant cultivated in the tropics of Asia and South Africa. Among the major constraints, phyllody associated with phytoplasma presence is the major limiting factor affecting its cultivation firstly described more than 100 years ago. Almost all the sesame varieties under cultivation are susceptible to the disease that continues to cause severe economic losses. Different symptomatology is present: the most common symptoms are phyllody, flower virescence and witches’ broom affecting growth and yield. Several detection methods like Diene's stains and TEM techniques were developed for the detection of phytoplasmas in phloem sieve tissues, however the PCR based assays were established for the identification of the phytoplasmas associated with the disease. After rRNA sequencing and restriction analyses, a wide genetic diversity was identified among sesame phyllody associated phytoplasmas: four ribosomal groups 16SrI, 16SrII, 16SrVI and 16SrIX were detected. The disease spreads in nature by different leafhopper species, among them Orosius orientalis was reported as the major vector. Moreover many weed species are reported hosts of the sesame phyllody-associated phytoplasmas. No effective control measures of the disease were developed, exceptresistance, management of insect vectors andaltering the dates of sowing to avoid peaks of insect vector population. So far no resistant genotype of sesame is available. However, attempts have been made to confer resistance against the phyllody disease in sesame through intra-and interspecific crosses of two wild species Sesamum mulayanum and S. alatum. The review reports uptodate information about history, geographic distribution, symptomatology, diagnosis, genetic diversity, epidemiology and management of sesame phyllody disease.

Molecular identification, characterization and transmission of phytoplasmas associated with sesame phyllody in Turkey

Phyllody is a destructive disease of sesame in Turkey. The disease has been causing significant economic losses by stunting the plants and altering their floral parts into leafy structures with no capsule and hence no seeds in sesame fields of the country. This research was undertaken to examine symptomatology, etiology, taxonomy and transmission of two recently discovered phyllody phytoplasmas infecting sesame in Turkey. Direct and nested PCR amplifications of 16S rRNA gene with the phytoplasma-specific universal primers P1/P7 and R16F2n/R2, respectively were employed for identification of the phytoplasmas associated with sesame phyllody. Phytoplasma-specific PCR amplicons of 1.8 kb and 1.2 kb were amplified only from symptomatic sesame plants and insect vector samples. Sequencing of the PCR amplicons and computer simulated restriction fragment length polymorphism analysis allowed classification of the phytoplasmas with pigeon pea witches’-broom (16SrIX-C) and peanut witches’-broom (16SrII-D) groups. The sequence homology and phylogenetic analyses further confirmed this classification. Among the insects collected from the sesame fields, the leafhopper Orosius orientalis Matsumara (Syn: O. albicinctus Distant) was the only vector proven to transmit the sesame phyllody phytoplasmas from diseased to healthy sesame plants in transmission assays. The results demonstrated that the 16SrIX-C and 16SrII-D group phytoplasmas were the agent of sesame phyllody and O. orientalis was the vector insect of the disease in Turkey.

EPG monitoring of the probing behaviour of the common brown leafhopper Orosius orientalis on artificial diet and selected host plants

The common brown leafhopper Orosius orientalis (Hemiptera: Cicadellidae) is a polyphagous vector of a range of economically important pathogens, including phytoplasmas and viruses, which infect a diverse range of crops. Studies on the plant penetration behaviour by O. orientalis were conducted using the electrical penetration graph (EPG) technique to assist in the characterisation of pathogen acquisition and transmission. EPG waveforms representing different probing activities were acquired from adult O. orientalis probing in planta, using two host species, tobacco Nicotiana tabacum and bean Phaseolus vulgaris, and in vitro using a simple sucrose-based artificial diet. Five waveforms (O1–O5) were evident when O. orientalis fed on bean, whereas only four waveforms (O1–O4) and three waveforms (O1–O3) were observed when the leafhopper fed on tobacco and on the artificial diet, respectively. Both the mean duration of each waveform and waveform type differed markedly depending on the food substrate. Waveform O4 was not observed on the artificial diet and occurred relatively rarely on tobacco plants when compared with bean plants. Waveform O5 was only observed with leafhoppers probing on beans. The attributes of the waveforms and comparative analyses with previously published Hemipteran data are presented and discussed, but further characterisation studies will be needed to confirm our suggestions.

Diversity of Cicadellidae in agricultural production areas in the Ovens Valley, north‐east Victoria, Australia

AbstractThere is a paucity of data on the distribution of Cicadellidae (leafhoppers) in Australia. This study quantifies the relative abundance, seasonal activity and diversity of leafhoppers in the Ovens Valley region of north‐east Victoria, Australia. Species diversity and abundance was assessed at four field sites in and around the field borders of commercially grown tobacco crops using three sampling techniques (pan trap, sticky trap and sweep net). Over 51 000 leafhopper samples were collected, with 57 species from 11 subfamilies and 19 tribes identified. Greater numbers and diversity of leafhoppers were collected in yellow pan traps. The predominant leafhopper collected was Orosius orientalis (Matsumura). Twenty‐three leafhopper species were recorded for the first time in Victoria and eight economically important pest species were recorded. Seasonal activity of selected leafhopper species, covering two sampling seasons, is presented.

Vectors and alternative hosts of Tobacco yellow dwarf virus in southeastern Australia

Factors that determine the epidemiology of Tobacco yellow dwarf virus (TbYDV), including alternative host plants and insect vector(s), were assessed over three consecutive growing seasons at four field sites in Northeastern Victoria in commercial tobacco growing properties. In addition, these factors were assessed for one growing season at three bean growing properties. Overall, 23 leafhopper species were identified at the 7 sites, with Orosius orientalis as the predominant leafhopper. Of the leafhoppers collected, only O. orientalis and Anzygina zealandica tested positive for TbYDV by polymerase chain reaction (PCR). The population dynamics of O. orientalis was assessed using sweep net sampling over three growing seasons and a trimodal distribution was observed. Despite large numbers of O. orientalis occurring early in the growing season (September–October), TbYDV was only detected in these leafhoppers between late November and end of January. The peaks in the detection of TbYDV in O. orientalis correlated with the observation of disease symptoms in tobacco and bean and were associated with warmer temperatures and lower rainfall. Spatial and temporal distribution of vegetation at selected sites was determined using quadrat sampling. Of the 40 plant species identified, TbYDV was detected only in four dicotyledonous species, Amaranthus retroflexus, Phaseolus vulgaris, Nicotiana tabacum and Raphanus raphanistrum. The proportion of host and non‐host availability for leafhoppers was associated with climatic conditions.

Seasonal activity and abundance of Orosius orientalis (Hemiptera: Cicadellidae) at agricultural sites in Southeastern Australia

Abstract Orosius orientalis is a leafhopper vector of several viruses and phytoplasmas affecting a broad range of agricultural crops. Sweep net, yellow pan trap and yellow sticky trap collection techniques were evaluated. Seasonal distribution of O. orientalis was surveyed over two successive growing seasons around the borders of commercially grown tobacco crops. Orosius orientalis seasonal activity as assessed using pan and sticky traps was characterised by a trimodal peak and relative abundance as assessed using sweep nets differed between field sites with peak activity occurring in spring and summer months. Yellow pan traps consistently trapped a higher number of O. orientalis than yellow sticky traps.

SYMPTOMATOLOGY, ETIOLOGY AND TRANSMISSION OF CHICKPEA PHYLLODY DISEASE IN PAKISTAN

SUMMARY Chickpea (Cicer arietinum) plants of two types, kabuli and desi, showing phytoplasma disease-like symptoms were observed for the first time in Pakistan during 2005. The major symptoms were floral virescence, phyllody and extensive proliferation of the branches. Light microscopy of hand-cut sections of symptomatic stems treated with Dienes’ stain showed blue areas in the phloem region of diseased plants but not in apparently normal ones. Phytoplasma-like pleomorphic bodies were observed in the sieve cells of symptomatic chickpea stems by transmission electron microscopy, but not in the sieve tubes of healthy plants. Amplification from diseased plants of a 16S rDNA fragment 1800 bp in size with phytoplasma primers P1 and P7, confirmed that they hosted a phytoplasma. RFLP profiles and complete sequencing of the R16F2n/R16R2 region showed that the associated phytoplasma had 100% sequence identity in this rDNA region to 16SrII-D subgroup phytoplasmas. Chickpea phyllody disease was transmitted from diseased to healthy chickpea plants by grafting and through the leafhopper Orosius orientalis. Sap inoculation trials were unsuccessful and transmission by Aphis craccivora, Myzus persicae, Empoasca devastans and an unidentified brown leafhopper failed to produce disease symptoms.

Anti‐metabolic effects of Galanthus nivalis agglutinin and wheat germ agglutinin on nymphal stages of the common brown leafhopper using a novel artificial diet system

The common brown leafhopper, Orosius orientalis (Matsumura) (Homoptera: Cicadellidae), previously described as Orosius argentatus (Evans), is an important vector of several viruses and phytoplasmas worldwide. In Australia, phytoplasmas vectored by O. orientalis cause a range of economically important diseases, including legume little leaf (Hutton & Grylls, 1956), tomato big bud (Osmelak, 1986), lucerne witches broom (Helson, 1951), potato purple top wilt (Harding & Teakle, 1985), and Australian lucerne yellows (Pilkington et al., 2004). Orosius orientalis also transmits Tobacco yellow dwarf virus (TYDV; genus Mastrevirus, family Geminiviridae) to beans, causing bean summer death disease (Ballantyne, 1968), and to tobacco, causing tobacco yellow dwarf disease (Hill, 1937, 1941). TYDV has only been recorded in Australia to date. Both diseases result in significant production and quality losses (Ballantyne, 1968; Thomas, 1979; Moran & Rodoni, 1999). Although direct damage caused by leafhopper feeding has been observed, it is relatively minor compared to the losses resulting from disease (P Tr E bicki, unpubl.).

Physical Control of Leafhoppers

In 2000, a severe outbreak of phytoplasma-caused disease in Limonium spp. flowers devastated the industry in Israel; insecticides were not able to knock down and kill leafhopper vectors before they could transmit the pathogen. Nonchoice laboratory studies were conducted to determine the effect of UV-absorbing plastics on the movement of leafhoppers toward light; UV-absorbing plastic significantly reduced leafhopper movement. In choice trials conducted in sunlight, significantly more leafhoppers moved into the cage covered with regular plastic as opposed to the cage covered with UV-absorbing plastic. Field studies were conducted to determine at what height leafhoppers enter 2.5-3-m high walk-in tunnels; the majority enter the tunnels low to the ground, up to 1 m. Finally, field studies were conduced to compare leafhopper population levels in walk-in tunnels covered with UV-absorbing plastic or screening, and with ventilation holes at different heights above the ground. Elevated ventilation holes and UV-absorbing tunnel covering significantly reduced Orosius orientalis entrance into tunnels. Ramifications of these finding for leafhopper control are discussed.

Physical Control of Leafhoppers

In 2000, a severe outbreak of phytoplasma-caused disease in Limonium spp. flowers devastated the industry in Israel; insecticides were not able to knock down and kill leafhopper vectors before they could transmit the pathogen. Nonchoice laboratory studies were conducted to determine the effect of UV-absorbing plastics on the movement of leafhoppers toward light; UV-absorbing plastic significantly reduced leafhopper movement. In choice trials conducted in sunlight, significantly more leafhoppers moved into the cage covered with regular plastic as opposed to the cage covered with UV-absorbing plastic. Field studies were conducted to determine at what height leafhoppers enter 2.5–3-m high walk-in tunnels; the majority enter the tunnels low to the ground, up to 1 m. Finally, field studies were conduced to compare leafhopper population levels in walk-in tunnels covered with UV-absorbing plastic or screening, and with ventilation holes at different heights above the ground. Elevated ventilation holes and UV-absorbing tunnel covering significantly reduced Orosius orientalis entrance into tunnels. Ramifications of these finding for leafhopper control are discussed.

PCR DETECTION AND PARTIAL MOLECULAR CHARACTERIZATION OF CHICKPEA CHLOROTIC DWARF VIRUS IN NATURALLY INFECTED SUGAR BEET PLANTS IN IRAN

SUMMARY The causal agent of mild chlorosis and stunting of sugar beet in Iran was identified as Chickpea chlorotic dwarf virus (CpCDV). The virus reacted positively with CpCDV-specific antibodies in ELISA, but not with antibodies specific to other viruses of the family Geminiviridae (Beet curly top virus, Bean golden mosaic virus and Tomato yellow leaf curl virus). The virus isolate under study (SK-11) was transmitted by grafting and by the leafhopper Orosius orientalis Matsumara to a range of plant species in the Chenopodiaceae, Fabaceae and Solanaceae, and induced symptoms like those reported for CpCDV. By using a pair of degenerate primers, a short viral genome fragment was amplified by PCR, cloned and sequenced, revealing a close homology to Bean yellow dwarf virus (84.9%-85.3% identity), and a more distant relationship to Tobacco yellow dwarf virus (58.8%). In the present study, two specific primers were designed for detecting CpCDV which allowed the amplification of a DNA fragment of 0.64 kbp. Using these primers, the virus was successfully detected in symptomatic sugar beet field samples collected from the main sugar beet production provinces of Iran. This study reports for the first time information on the genome sequence of CpCDV.

Intraspecific variation within Orosius argentatus Evans (Hemiptera: Cicadellidae): colour polymorphisms, morphometric analyses and host associations

Abstract Orosius argentatus shows extreme colour variation and is reputedly highly polyphagous, circumstances that both warrant confirmation that the taxon comprises only one species. Because the species transmits phytoplasma pathogens between plants, information on species status is relevant to epidemiological studies. Replicated field samples, taken in Mareeba, North Queensland, over 2 years indicated that O. argentatus is the most abundant leaf‐hopper in stylo (Stylosanthes scabra) and is relatively host‐specific on cultivated stylo, at least locally. A priori groupings of colour types were established for morphometric analyses of head, prothorax, tibia, wing and genitalia characters. No consistent morphological differences were detected across the colour types, and results from colour heritability trials, although limited, revealed that females could produce progeny that belong to multiple colour types. The results from this study suggest individuals that key out to the species O. argentatus, despite being polymorphic in colour, cannot be clearly separated on any morphological basis and therefore are likely to belong to a single, interbreeding population. The colour variation in adults is therefore a polymorphism.