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Fulgoraecia melanoleuca (Fletcher) is an important ecto-parasitoid of Pyrilla perpusilla (Walker) nymphs and adults. The study aimed to standardize the augmentative releases of F. melanoleuca life stages (eggs and cocoons) for eco-friendly management of P. perpusilla in sugarcane crop. The releases of F. melanoleuca cocoons (2000, 4000, and 6000 cocoons ha−1) and eggs (0.2, 0.4, and 0.6 million eggs ha−1) were compared with chemical control (chlorpyriphos 20 EC @1500 ml ha−1) and untreated control. Two releases were carried out at monthly interval during 1st week of August and 1st week of September. The pyrilla population decreased progressively with increase in released cocoons (2000, 4000, and 6000 ha−1) and eggs (0.2, 0.4, and 0.6 million ha−1). The augmentative releases play a noteworthy role in increasing the parasitoid count (egg masses, cocoons and adults) in the released plots. Overall, the parasitism (nymph + adult) increased with increase in doses and it was significantly higher when parasitoids were released at higher doses, i.e. 0.6 million eggs ha−1 (52.80%) and 6000 cocoons ha−1 (50.60%). However, chlorpyriphos 20 EC (1500 ml ha−1) was found to be highly detrimental to the parasitoid as no parasitism was observed in insecticide-sprayed plots. In conclusion, two releases of F. melanoleuca parasitoid (0.6 million eggs ha−1 or 6000 cocoons ha−1) at monthly interval (1st week of August and 1st week of September) proved better due to higher parasitism rate, increase in parasitoid population, and reduction in pyrilla population and also rendered higher cane yield and better juice quality. The findings will help in the eco-friendly management of P. perpusilla in sugarcane. [ABSTRACT FROM AUTHOR]

A total of 151 genotypes of durum and bread wheat exhibiting symptoms of stunting and bushy growth, leaf yellowing, and drying of clumps were recorded at ICAR-IARI Regional Station, Indore, Madhya Pradesh, India from 2016 to 2018. The disease incidence was recorded more in durum wheat genotypes as compared to bread wheat genotypes. The presence of any virus, bacterial, and fungal pathogens was ruled out by applying cultural growth and electron microscopy. However, association of phytoplasmas presence was confirmed in 142 (out of 151) durum and bread wheat genotypes by employing PCR primer pairs of 16S rRNA, leuS and secA genes. The sequence analysis of all the genes and in silico RFLP analysis of 16S rDNA sequences of wheat phytoplasma strains identified them as rice yellow dwarf group (16SrXI-B) and Bermuda grass white leaf group (16SrXIV-A). Two symptomatic weed species (Parthenium hysterophorus and Cleome gynandra) tested positive for 16SrXI-B phytoplasma subgroup and four weed species (Cynodon dactylon, Digitaria sanguinalis, Euphorbia hirta and Rhynchosia minima) for 16SrXIV-A phytoplasma subgroup growing in and around wheat fields. Six hopper species identified from symptomatic wheat fields were also analyzed for phytoplasma presence. Three hopper species viz., Sogatella furcifera, Balclutha rubrostriata, and Exitianus indicus were tested positive to phytoplasmas in 16SrXIV group, while Sogatella kolophon, Cofana unimaculata, and Maiestas sp. tested positive to 16SrXI group of phytoplasmas in nested PCR assays. Transmission assays revealed that S. furcifera and B. rubrostriata successfully transmitted the 16SrXIV-A strain from infected wheat to healthy wheat plants; however, C. unimaculata was able to transmit 16SrXI-B subgroup from infected wheat to healthy wheat plants under glasshouse conditions. A variation in phytoplasma associated disease incidence was recorded on wheat genotypes in different years and was also found positively correlated with temperature, humidity, and hopper population. The identification of similar phytoplasma strains (16SrXI and 16SrXIV group) from wheat, weeds, and hoppers indicated potential risk of transmission of these strains to wheat genotypes and other agricultural crops, which needs further investigations on epidemiological aspects. [ABSTRACT FROM AUTHOR]

The recent surge in sweet potato (Ipomoea batatas) cultivation in Europe prompted an investigation into associated entomofauna within Portugal's southwestern region, known for its longstanding sweet potato production. This study aimed to assess entomofauna associated with this culture. Insect sampling was conducted by leaf and sweep net across three regional sites during 2018 and 2019 revealing the presence of Empoasca fabalis. Histological examination of sweet potato leaves affected by E. fabalis feeding unveiled significant damage, including the emergence of whitish spots (termed “stipples”) and subsequent necrotic spots. Comparative analysis between infested and undamaged control leaves revealed significant damage, involving mesophyll cell content deprivation and cellular disruption. This study describes, for the first time, the histological nature of the necrotic damage and suggests that E. fabalis primarily acts as a stippler on sweet potatoes, mainly targeting mesophyll cells with limited consumption of vascular tissue. The invasive behaviour and wide host range of E. fabalis pose a threat to sweet potato cultivation. These findings emphasize the need for monitoring to address the potential impact of E. fabalis on Europe’s agricultural ecosystem and native vegetation. In addition, six other Auchenorrhyncha species were identified during this study, including four crucial vectors of plant diseases: Laodelphax striatellus, Psammotettix alienus, Anaceratagallia glabra, Austroagallia sinuata, together with Empoasca solani and E. alsiosa. These results emphasise the importance of managing these insects in sweet potato cultivation. [ABSTRACT FROM AUTHOR]

Whitefly, Bemisia tabaci (Gennadius), and leafhopper, Amrasca biguttulla biguttulla, Ishida, are the major biotic constraints in cultivation of okra, causing considerable economic damage. The present study aims to evaluate the laboratory and field efficacy of butenolide insecticide, flupyradifurone 200 SL against these key sucking pests, its phytotoxicity, safety to natural enemies as well as pollinators and cost-efficiency in okra. Dose probit mortality assays indicated flupyradifurone to be the most toxic and thiamethoxam least toxic to leafhopper and whitefly. Based on the LC50 values for whitefly and leafhopper, flupyradifurone exhibited 11.07 and 2.98-fold difference, respectively, when compared to thiamethoxam. Laboratory bioassays confirmed that the maximum dose of flupyradifurone (250 g a.i. ha−1) had a high level of toxicity to whitefly adults and leafhopper nymphs. Of the three field rates (150, 200, 250 g a.i. ha−1) of flupyradifurone evaluated under open field conditions, application at 250 g a.i. ha−1 was most effective for the control of whitefly and leafhopper population with a high marketable fruit yield in okra. Flupyradifurone reduced the population of whitefly by 71.80 & 76.68 per cent and leafhopper by 82.19 and 80.21 per cent during first and second season, respectively, as compared to untreated control. Furthermore, it was superior and more economical, giving the highest benefit: cost ratio (2.77) than other test insecticides included for comparison. Flupyradifurone application showed no phytotoxic symptoms on the okra crop. Additionally, it was found to be safer to natural enemies i.e. spiders and rove beetles that are prevalent in the okra ecosystem. The Kaplan–Meier survival analysis showed that flupyradifurone was apparently less toxic to honey bees in short-term and long-term exposure assays. These findings will aid in utilizing the flupyradifurone in insecticide window spray schedules and IPM programs for the management of sucking pests in okra. [ABSTRACT FROM AUTHOR]

The leafhopper Matsumuratettix hiroglyphicus is the vector of the phytoplasma associated with sugarcane white leaf disease in Asia. However, highly virulent strains of entomopathogenic fungi to control this vector are lacking. To select effective fungal strains, serial passaging through the leafhopper and the phenotypic properties and virulence of four strains were evaluated and compared to those of their initial stock. The influence of fungal passaging through the insect varied according to the fungal genus, strain, and passage number. The third and fifth passages of all fungal strains improved the examined parameters and showed virulence enhancement compared to those of the initial stock; however, a decrease in the parameters was observed after the seventh passage. The fifth passage of Beauveria bassiana SUTTU01 exhibited phenotypic changes resulting in significantly higher pathogenicity (80% mortality) than its corresponding initial stock. When the effect of fungal treatment on the transmission capacity of M. hiroglyphicus was tested, no significant difference was found in white leaf disease-related phytoplasma infection between untreated and fungi-treated leafhoppers. However, the fifth passage of B. bassiana SUTTU01-treated leafhoppers exhibited the lowest titer of the phytoplasma, resulting in a reduced transmission rate and fewer infected plants. This is the first report on the influence of B. bassiana on leafhopper vector capacity. The results obtained constitute a basis for future research on effective fungal strains able to reduce the phytoplasma transmission rate of this leafhopper vector. [ABSTRACT FROM AUTHOR]

Here, we report a novel wheat-infecting marafivirus, tentatively named "Triticum aestivum marafivirus" (TaMRV). The full-length genome sequence of TaMRV comprises 6,437 nucleotides, excluding the poly(A) tail. Pairwise sequence comparisons and phylogenetic analysis revealed that TaMRV may represent a novel species within the genus Marafivirus in the family Tymoviridae. We also observed a mass of isometric particles with a diameter of about 30 nm in ultrathin sections of infected wheat leaf tissue. In addition, the leafhopper Psammotettix alienus was identified as a vector for this virus. This is the first report of the occurrence of a wheat-infecting marafivirus. [ABSTRACT FROM AUTHOR]

Brochosomes, which are nanoscopic buckyball-shaped granules produced by leafhoppers, are one of the most intricate structures discovered in nature. Various functions of brochosomes have been proposed but only a few have been experimentally validated due to the challenge of fabricating their synthetic counterparts. Advancements in micro- and nanofabrication have recently led to the emergence of synthetic brochosomes, opening up new possibilities for innovative applications. This review explores the early discovery of natural brochosomes and their geometrical features, followed by the recent progress in fabricating synthetic brochosomes and their applications. Perspectives on future applications and challenges in the scalable manufacturing of synthetic brochosomes are discussed. [ABSTRACT FROM AUTHOR]

We evaluated the induction of plant volatile organic compounds (VOCs) in maize after the attack of two piercing-sucking maize hoppers: the specialist Dalbulus maidis and the oligophagous Peregrinus maidis. We analyzed VOCs in plants after feeding and oviposition by females of both species. We also contrasted VOCs induced by D. maidis males with those induced by females' infestation that comprised oviposition, to evaluate which VOC could be responsible for attracting an egg parasitoid. We quantified the damage performed by both hoppers and tested the behavioral response of the egg parasitoid Anagrus virlai to VOCs emitted by infested and healthy plants. Plants infested by D. maidis females released significantly more VOCs than the other treatments: healthy plants, plants infested by P. maidis females and plants infested by D. maidis males. β-Caryophyllene, α-bergamotene, β-farnesene and cis-3-hexenyl acetate dominated the volatile blend (46%) in plants infested by D. maidis females, while in those plants infested by P. maidis these compounds represented only 17%. Females of both hoppers inflicted a comparable amount of damage, in terms of feeding injuries and number of eggs laid. β-Caryophyllene and cis-3-hexenyl acetate were not induced in plants infested by D. maidis males, that had no oviposited eggs. Finally, females of the egg parasitoid oriented toward VOCs from plants infested by females of the specialist D. maidis, rather than those infested by the oligophagous P. maidis or those infested by D. maidis males. [ABSTRACT FROM AUTHOR]

The corn leafhopper Dalbulus maidis (Hemiptera: Cicadellidae) is a serious maize pest widely distributed on the American continent. This is the most common leafhopper feeding on corn crops in Argentina and Brazil, causing major economic losses due to its capability to transmit important pathogens, such as corn stunt spiroplasma, and considerably decreasing crop yield. One way to increase crop yield is to elevate fertilizing doses of nitrogen and phosphorus, although this could translate into an increase in pest populations, since changes in host plant quality makes them more attractive to herbivorous insects, positively influencing their population dynamics. This study aims to assess the oviposition preference and the olfactory response of D. maidis to corn plants subject to three levels of nitrogen fertilization (100 ppm, 200 ppm and 300 ppm). Olfactory response was evaluated in a static-air four-way olfactometer using maize plants with different nitrogen fertilization levels as odor sources. Additionally, plants with different nitrogen fertilization levels were offered to females in a multiple-choice assay to assess their oviposition preference. The olfactory response of D. maidis was influenced by nitrogen fertilization, as females oriented toward plants treated with high fertilization levels. Similarly, oviposition preference assays showed that D. maidis females preferred to lay its egg in plants with high fertilization levels. The results herein reported could contribute to the design of integrated pest management strategies that promote balance between crop fertilization to improve yield and insect vector management. [ABSTRACT FROM AUTHOR]

The aster leafhopper Macrosteles fascifrons is a common insect pest that feeds on rice and other plants and may serve as a vector to transmit various viruses. Here, we discovered a novel virus from M. fascifrons using metagenomic sequencing. We obtained its complete genome sequence by contig assembly and rapid amplification of cDNA ends, and verified the genome sequence by Sanger sequencing of overlapping segments. Based on homology search and phylogenetic analysis, the new virus belongs to the family Iflaviridae and it is tentatively named "Macrosteles fascifrons iflavirus 1" (MfIV1). Excluding the poly(A) tail, the MfIV1 genome is 10,581 nucleotides in length and it is predicted to encode a polyprotein of 3119 amino acids long, which is likely further processed to several polypeptides with conserved domains, including two rhinovirus like (rhv-like) capsid domains, a cricket paralysis virus (CRPV) capsid domain, a helicase domain, and an RNA-dependent RNA polymerase (RdRp) domain. BLAST searches show that the highest amino acid sequence identity between the capsid proteins of MfIV1 and those of other reported iflaviruses is 60.22%, indicating that MfIV1 is a new member in the family Iflaviridae. [ABSTRACT FROM AUTHOR]

Symptoms of leaf yellowing, reddening, witches' broom and declining were observed in peach, apricot, and plum orchards from two states and a union territory [Himachal Pradesh (H.P.), Uttarakhand and Jammu & Kashmir (J&K)] of India during 2019–2021. Association of three groups (16SrI, 16SrII,16SrV) of phytoplasma were confirmed in symptomatic peach, plum and apricot samples by amplifying DNA using 16S rRNA and multiple non-ribosomal primers (secA, secY, tuf). Pair wise sequence comparison, phylogenetic analysis and virtual RFLP analysis using multiple non-ribosomal gene sequences confirmed the presence of 'Candidatus Phytoplasma asteris' (16SrI-B), 'Ca. Phytoplasma australasia' (16SrII-D), elm yellows (new subgroup variant of 16SrV) and 'Ca. Phytoplasma ziziphi' (16SrV-B) related strains in peach, plum and apricot trees. Besides, other suspected symptomatic plant hosts and weeds in and around stone fruit orchards were also identified positive with phytoplasma strains belonging to 16SrI-B and 16Sr II-D subgroups by amplifying 16SrRNA and secA genes and sequence analysis. Association of similar strains of phytoplasma was identified in leafhopper species, Hishimonus phycitis from J&K and Empoasca sp. from Uttarakhand by utilizing the same set of primer pairs and 16S rRNA and secA gene sequence comparison. The presence of 'Ca. P. asteris' (16SrI-B) and 'Ca. P. australasia' (16SrII-D) related strains detected in peach are new host records from India and the association of elm yellows (a variant of 16SrV subgroup) related strain in plum is the first report in the world. [ABSTRACT FROM AUTHOR]

Maize streak virus (MSV) is a major threat to cereal production, hence food security in sub-Saharan Africa. The virus is spread mainly by insect vectors. The leafhoppers composition and distribution of potential MSV vectors were evaluated, and the performance of various control techniques against the vectors assessed in the major maize production areas of Cameroon. These techniques included the use of botanical extracts of Azadirachta indica A Juss. and Chenopodium ambrosoides L. Mosyakin and Clements, intercropping maize with cassava and soybean, and use of the synthetic insecticides Imidacloprid. The infection coefficient of maize streak disease and the abundance of leafhoppers were assessed in three agro-ecological zones of Cameroon (AEZs) including the Sudano-Sahelian zone (AEZ I), the Western highlands (AEZ III) and the humid forest with bimodal rainfall (AEZ V). Among 15 leafhoppers species recorded, 15 were recorded in AEZ I; 14 in AEZ III and 12 in AEZ V. The most abundant species in each AEZ was Afrosteles distans (Linnavuori) while the least abundant was Aconurella erebus (Distant). Intercropping maize with cassava and maize with soybean significantly reduced the infection coefficient of MSV in the different study zones. Also, phytochemical treatments significantly performed well with neem being the most efficient in the reduction of abundance compared to the other treatments. Thus, the use of the plant extracts and intercropping against leafhopper vectors of MSV effective. [ABSTRACT FROM AUTHOR]

Intracellular polyamines (putrescine, spermidine, and spermine) have emerged as important molecules for viral infection; however, how viruses activate polyamines biosynthesis to promote viral infection remains unclear. Ornithine decarboxylase 1 (ODC1) and its antienzyme 1 (OAZ1) are major regulators of polyamine biosynthesis in animal cells. Here, we report that rice yellow stunt virus (RYSV), a plant rhabdovirus, could activate putrescine biosynthesis in leafhoppers to promote viral propagation by inhibiting OAZ1 expression. We observed that the reduction of putrescine biosynthesis by treatment with difluormethylornithine (DFMO), a specific nontoxic inhibitor of ODC1, or with in vitro synthesized dsRNAs targeting ODC1 mRNA could inhibit viral infection. In contrast, the supplement of putrescine or the increase of putrescine biosynthesis by treatment with dsRNAs targeting OAZ1 mRNA could facilitate viral infection. We further determined that both RYSV matrix protein M and ODC1 directly bind to the ODC-binding domain at the C-terminus of OAZ1. Thus, viral propagation in leafhoppers would decrease the ability of OAZ1 to target and mediate the degradation of ODC1, which finally activates putrescine production to benefit viral propagation. This work reveals that polyamine-metabolizing enzymes are directly exploited by a vector-borne virus to increase polyamine production, thereby facilitating viral infection in insect vectors. [ABSTRACT FROM AUTHOR]

Purpose: Beneficial soil microbes, such as rhizobia, engage in facultative symbioses in the roots of leguminous host plants to exchange nitrogen for products of photosynthesis, and these symbioses can be altered by biotic and abiotic factors. Here, we investigated how soil nitrate supply and aboveground insect herbivory interact to influence biological nitrogen fixation in Medicago sativa (alfalfa or lucerne). Methods: Using field and greenhouse experiments, we quantified above- and belowground allocation of rhizobially fixed nitrogen using isotopic nitrogen ratios in plants with different combinations of herbivory and nitrate supplementation. We caged Empoasca fabae (potato leafhopper) on fixing and non-fixing cultivars of M. sativa and supplemented soils with varied nitrate concentrations. Results: We detected strong changes in legume above- and belowground allocation of fixed nitrogen in response to both herbivory and nitrate supply. Moderate nitrate soils, irrespective of herbivory, induced little to no fixed nitrogen allocation across both field and greenhouse experiments. In the field only, non-supplemented soil increased aboveground allocation of fixed nitrogen following herbivore damage but resulted in no changes belowground. In contrast, non-supplemented and high nitrate soils in the greenhouse increased above- and belowground fixed nitrogen allocation relative to moderate nitrate soils. Conclusion: Our results demonstrate herbivory drives distinct plant allocation strategies across soil nitrate levels, advancing our understanding of how rhizobia influence legumes both above- and belowground. Herbivory-induced changes in rhizobia-legume symbioses are likely widespread across both agricultural and natural ecosystems. [ABSTRACT FROM AUTHOR]

The morphology of the antennae of adult specimens of Goniagnathus punctifer (Walker, 1858), Stirellus yeongnamensis (Kwon and Lee, 1979) and Stirellus indrus (Distant, 1908) was studied using SEM (scanning electron microscope). The antennae of these three leafhopper species are similar overall to antennae of other leafhoppers, consisting of three segments: a short scape, a cylindrical pedicel and an elongate, hair-like flagellum. Five kinds of sensilla are found on G. punctifer, including two types of sensilla trichodea (St I and St II), two types of sensilla basiconica (Sb I and Sb II), one type of sensilla chaetica (Sch I), two types of sensilla coeloconica (Sco I and Sco II), and one type of sensilla campaniformia (Sca I). Sensilla on the 1st and 2nd flagellomere of male G. punctifer tentatively identified as Sb II have a unique shape not yet observed in other leafhoppers. Five kinds of sensilla are found on S. yeongnamensis, including two types of sensilla trichodea (St I and St II), one type of sensilla basiconica (Sb I), two types of sensilla chaetica (Sch I and Sch II), one type of sensilla coeloconica (Sco I), and two types of sensilla campaniformia (Sca I and Sca II). Five kinds of sensilla are found on S. indrus, including two types of sensilla trichodea (St I and St II), one type of sensilla basiconica (Sb I), two types of sensilla chaetica (Sch I and Sch II), two types of sensilla coeloconica (Sco I and Sco II) and one type of sensilla campaniformia (Sca II). The antennal surfaces of these three leafhopper species also have large numbers of brochosomes and squamiform denticles. No significant differences in antennal morphology were observed between males and females of Stirellus Osborn and Ball, 1902. A table summarizing types and locations of antennal sensilla in previously studied leafhoppers is provided. [ABSTRACT FROM AUTHOR]

Leafhoppers (Cicadellidae) occur in all biogeographical regions and feed on a wide range of host plants. Classic identification of leafhoppers is based only on the morphology of male genitalia, while DNA barcoding is an effective tool to identify different leafhopper species in any stage of their life cycle. Phylogenetic relationships among leafhoppers remain unexplored, but recent phylogenies have begun to interpret the evolutionary relationships of previously recognized tribes and subfamilies. Here we used mitochondrial Cytochrome Oxidase I sequences to barcode and determine the phylogenetic relationship among eight leafhopper genera collected from Egypt. Eight leafhopper samples from eight different genera were collected from various plants using a sweeping net and aspirator. Males of seven species were available while females only were available from the one genus (Austroagallia sp.). Novel leafhopper-specific mtDNA COI degenerate primers were designed. Our results showed that the mean of intraspecific COI sequence divergence in leafhoppers was 0.45%, with a range from 0.15% to 1.23%, and the divergences of most species were over 2%. For the first time, we were exploring the evolutionary relationships among surveyed genera (Austroagallia, Empoasca, Eupteryx, Exitianus, Macrosteles, Nephotettix, and Orosius) using a robust phylogenetic supertree. Our results demonstrate that DNA barcoding is likely to be a powerful tool for identifying and understanding leafhoppers' evolution. [ABSTRACT FROM AUTHOR]

The morphology of adult mouthparts of the leafhoppers Alobaldia tobae, Maiestas dorsalis and Stirellus indrus was studied using a scanning electron microscope. The mouthparts are of the typical piercing–sucking type, similar to mouthparts found in other hemipteran insects, and comprise a three-segmented labium with a deep groove in the anterior side, a stylet fascicle consisting of two mandibular and two maxillary stylets, and a small cone-shaped labrum. The mandibular stylets, located laterad of the maxillary stylets, have sculpturing on their tips. The maxillary stylets are interlocked to form a larger food canal and a smaller salivary canal. Sensilla detected on the three leafhopper species were at different locations on the labium. Three kinds of sensilla were found on the Alobaldia tobae and Maiestas dorsalis labium, including two types of sensilla trichodea (I and II), two types of sensilla basiconica (I and II), and one type of sensilla coeloconica (Sco I). Three kinds of sensilla were found on the Stirellus indrus labium, including three types of sensilla trichodea (I, II and III), two types of sensilla basiconica (I and II), and one type of sensilla coeloconica (Sco I). Among them, sensilla trichodea I are the most abundant on all of three species. This is the first report of sensilla coeloconica (Sco I) and sensilla trichodea III on the mouthparts of Deltocephalinae. Sensilla trichodea I (St I) were also found on the surface of the Stirellus indrus labrum, which is also a first report in the Deltocephalinae. These sensilla may be involved in host recognition and are likely chemo- or mechanosensory, or both. The potential functions of the sensilla are discussed. The morphology of mouthparts and the distribution of sensilla on the labium in Alobaldia tobae, Maiestas dorsalis and Stirellus indrus are discussed with respect to their possible functional significance. [ABSTRACT FROM AUTHOR]

Peptidoglycan recognition proteins (PGRPs) contribute to the immune response of vertebrates and higher invertebrates. Animals have a varying number of PGRP genes: 4 in human and mouse, 13 in Drosophila, and 0 in an aphid. Transcriptome analyses revealed that numerous PGRP genes (> 300 in an RNA-Seq analysis) were expressed in the green rice leafhopper Nephotettix cincticeps (Uhler) (Hemiptera, Cicadellidae). PGRP genes were mostly expressed in the bacteriomes, in which two bacterial endosymbionts, Sulcia and Nasuia, are harbored. E. coli inoculation upregulated antimicrobial peptide gene expression in the leafhopper, whereas PGRP gene expression was not affected by the bacterial challenge. High and constant expression of PGRP genes in the bacteriomes and the lack of an immune response against invading bacteria suggest that these PGRPs play a hitherto unknown role in the bacteriomes, implicating a relationship with symbiotic association in N. cincticeps. [ABSTRACT FROM AUTHOR]

The glassy-winged sharpshooter (GWSS), Homalodisca vitripennis, is an important vector of Xylella fastidiosa, the causal agent of Pierce's disease of grapevine. GWSS control relies mainly on insecticides; therefore, an alternative method, such as vibrational mating disruption, is required. However, knowledge of GWSS intraspecific communication is necessary to evaluate applicability of such methods. Mating behavior and associated vibrational signals were described in different social contexts: individuals, pairs, and one female with two competing males. Behavioral analysis showed that GWSS mating communication involved the emission of three male and two female signals, with specific roles in two distinct phases of mating behavior, identification and courtship. Mating success depended on vibrational duets between genders, which were temporarily interrupted in the presence of male rivalry. Male rivalry behavior involved the emission of three distinct rivalry signals. Two rivalry signals resemble female signals and were associated with replacement of the female in the duet by the rival male. The third rivalry signal was emitted by competing males. Data suggested that rival males used mimicry and hostile signals to interrupt the ongoing duet and gain access to a female. In the future, knowledge acquired from this study will be essential to develop a mechanical mating disruption method for GWSS control. [ABSTRACT FROM AUTHOR]

High population levels of Osbornellus horvathi (Matsumura 1908) in Mediterranean natural environments and our previous findings of adults infected by ' Candidatus Phytoplasma phoenicium', in Sicily in 2012, highlight the potential role of this species as a phytoplasma vector. In the present work, O. horvathi and other Auchenorrhyncha species were collected using sticky traps between May-October of 2013 in a natural area in Sicily. The insects were analyzed for phytoplasma detection and characterization. Among the 20 Auchenorrhyncha species collected, only O. horvathi was positive for phytoplasmas. Phytoplasma transmission to periwinkle and broad bean plants by field-collected phytoplasma-infected O. horvathi individuals was also carried out. The number and composition of Auchenorrhyncha populations in the area were described together with information on the biology of O. horvathi. ' Candidatus Phytoplasma asteris' was successfully transmitted to broad bean and periwinkle by field-collected ' Ca. P. asteris' and ' Ca. P. phoenicium' double-infected O. horvathi, thus highlighting its vector competence for the former phytoplasma. Further studies are required to assess the ability of O. horvathi to transmit ' Ca. P. phoenicium'. [ABSTRACT FROM AUTHOR]

In general, leafhoppers (Hemiptera: Cicadellidae) possess a pair of bacteriomes in the abdomen, which harbor two types of obligate bacterial symbionts: a very ancient Sulcia symbiont and another ancient Nasuia-allied co-symbiont (or a younger Baumannia co-symbiont). However, when we inspected three eared leafhoppers of the subfamily Ledrinae, namely Ledra auditura Walker, Ledropsis discolor (Uhler) and Tituria angulata (Matsumura), L. discolor harbored only Sulcia symbiont while L. auditura and T. angulata possessed no bacterial symbionts. Instead, all the species possessed specialized cells full of yeast-like fungal symbionts within fat bodies. Molecular phylogenetic analysis revealed that the fungal symbionts are placed within the entomoparasitic fungal genus Ophiocordyceps (Ascomycota: Hypocreales: Ophiocordycipitaceae). These results suggest the possibility that (1) the fungal symbiont was acquired in the evolutionary course of the Ledrinae, (2) the original fungus was likely an entomoparasite of the genus Ophiocordyceps, (3) the fungal symbiont replaced the Nasuia-allied symbiont in an ancestral lineage, and (4) even the ancient Sulcia symbiont was finally lost and taken over by the fungal symbiont. Meanwhile, the possibility of multiple independent fungal acquisitions from closely related entomoparasitic Ophiocordyceps fungi cannot be excluded. Our finding uncovers an evolutionary process from a prokaryotic essential symbiosis to a eukaryotic one. [ABSTRACT FROM AUTHOR]

—The American grapevine leafhopper, Scaphoideus titanus Ball, 1932, a vector of flavescence doreé of grapevine, is recorded from the environs of Krasnodar and from the Taman' Peninsula in the Northwestern Caucasus for the first time. [ABSTRACT FROM AUTHOR]

During a survey of sugarcane fields at the Sugarcane Research Institute, Shahjahanpur, Uttar Pradesh, India, in August-September 2012, 6% to 28% incidence of sugarcane grassy shoot disease was observed in different fields of sugarcane variety CoS 7250. The association of phytoplasma with symptomatic sugarcane was confirmed by direct and nested PCR amplification of phytoplasma ribosomal gene. Four different delphacid leafhopper species, viz. Cofana unimaculata Signoret, Exitianus indicus (Distant), Sogatella kolophon Kirkaldy and Hishimonus phycitis (Dist.) were the prevalent feeding species of the Auchenorrhyncha fauna in the symptomatic sugarcane fields. Out of these four leafhopper species, only E. indicus tested positive for phytoplasma presence. Phylogenetic analysis suggested that the phytoplasmas from sugarcane and E. indicus in the present study were members of 16Sr XI. The confirmation of association of sugarcane grassy shoot phytoplasma in E. indicus population is important to understand the secondary spread of this phytoplasma in sugarcane plants. [ABSTRACT FROM AUTHOR]

Recently, disease in broccoli plants ( Brassica oleracea var. italica) was associated with three distinct phytoplasmas in Brazil. The disease named broccoli stunt (BS) has caused significant economic losses in São Paulo State. Group 16SrIII phytoplasmas is the most common group that have been associated with BS. The BS disease is still poorly understood, and the lack of information about the vectors further impairs its management. In this study, leafhoppers belonging to 18 different species were collected from weeds thriving near broccoli fields that were affected by group 16SrIII phytoplasmas. Specific primers revealed the presence of group 16SrIII phytoplasmas in five leafhoppers: Empoasca spp., Agallia albidula Uhler, Agalliana sticticollis (Stål), Planicephalus flavicosta (Stål), and Atanus nitidus (Linnavuori). The identity of the phytoplasmas was confirmed through DNA sequencing analysis. The leafhoppers were infected by phytoplasmas of the 16SrIII group (proposed ' Candidatus Phytoplasma pruni' species) and are phylogenetically related to the broccoli stunt phytoplasma (BSP) strains detected in the study area and, thus, are considered potential vectors of group 16SrIII phytoplasmas to broccoli plants. [ABSTRACT FROM AUTHOR]

Chickpea stunt disease caused by Chickpea chlorotic dwarf virus (CpCDV) (genus Mastrevirus, family Geminiviridae) is the most important biotic stress affecting chickpea crops worldwide. A survey conducted on the incidence of stunt disease clearly revealed high incidence of the disease with severe symptom expression in both indigenous and imported genotypes. To manage the disease in a sustainable way, resistant genotypes need to be bred by adopting objective and precise assessment of the disease response of chickpea genotypes. At present, evaluation of CpCDV resistance is conducted on the basis of natural infection in the field, which is bound to be erroneous due to vagaries in vector population. To circumvent the above problems, we devised an agroinoculation technique that involves the delivery of viral genomic DNA through Agrobacterium tumefaciens. An objective scoring system assigning quantitative value to different symptoms has been evolved to assess the response of chickpea genotypes to CpCDV inoculation. Using the inoculation and scoring techniques, we screened 70 genotypes, which helped in differentiating field resistance that is more due to resistance to vector feeding than resistance to the virus. [ABSTRACT FROM AUTHOR]

RNA interference (RNAi) is a useful tool for gene functional studies in non-model insects and pest insects. Establishment of experimental conditions for RNAi, which differ from insect to insect, is important for evaluating the effect of dsRNA injection of relevant genes. When injecting dsRNA into the green rice leafhopper Nephotettix cincticeps (Uhler), high mortality was observed. Therefore, the adverse effects of injection of dsRNA on leafhopper development were examined to assess the suitable conditions for RNAi in this species. Injection manipulation by using a glass capillary did not affect leafhopper survival but delayed the molt of the corresponding instar. High mortality was observed when large amounts of dsRNA were administered. This adverse effect of dsRNA was examined in 2 genes, exogenous EGFP gene and endogenous peptidoglycan recognition protein gene ( NcPGRP12). Injection of a high dose (60 ng/insect) caused high mortality in all stages tested: 4th instar, 5th instar, and female adult. A relatively low dose (6 ng/insect) did not cause high mortality, retaining a high potential for gene silencing. Since RNAi is highly effective in this species, the deleterious effect of large amounts of dsRNA could be avoided by administering a low dsRNA dose. [ABSTRACT FROM AUTHOR]

Present study was designed to determine the effect of various growing environments on sucking pest population dynamics in cotton and to work out their relation with spectral indices. Crop spectral reflectance in four IRS bands was measured with ground truth radiometer during 1000-1200 h in all the treatment combinations. Incidence of sucking pest in cotton was found out to be highly influenced by growing environments. The leafhopper and whitefly population was highest in 15 May sown cotton crop and was lowest in 15 April sown crop. Cultivar HS-6 was highly affected by both the sucking pest than the other cultivar H-1226. The spectral indices (SR, NDVI and TVI) were highest in 15 April sown crop at all the phenophases and were lowest in 15 May sown crop. The cultivar H-1226 showed higher values of spectral indices as compared to HS-6. The relationship of pests' population with various spectral indices was established. Multiple regression models based on spectral indices can be used for prediction of sucking pest population more than 69 and 74 % accuracy in leafhopper and whitefly, respectively in cotton crop. [ABSTRACT FROM AUTHOR]

Dicot-infecting mastreviruses affect chickpea ( Cicer arietinum) plants by causing extreme stunting of the plant and leaf lamina reduction. Chickpea stunt disease (CSD) is presently known to occur in Africa, the Middle East and Asia. Although the disease was first recorded in India, little was known about the pathogen causing the disease. In this study we determined the complete nucleotide sequence of the mastrevirus associated with CSD in the region of Delhi. The genomic component of the virus was cloned using a rolling circle amplification (RCA) method. The virus isolate was found to show 99% sequence identity with the Chickpea chlorotic dwarf Pakistan virus. The complete tandem dimeric construct of the virus was found to be highly infectious to chickpea, and induced severe stunting of the plant, leaf smalling, drying, and the eventual death of the plant. Phylogenetic analysis of all the chickpea-infecting mastreviruses helped to distinguish the current differences between viruses originating from Africa, the Middle East, Asia and Australia. [ABSTRACT FROM AUTHOR]

Mate recognition and location in Cicadellidae is mediated exclusively via substrate-borne vibrational signals. In the present study we investigated vibrational signals and mate searching behaviour of the leafhopper Aphrodes makarovi. We studied mating behaviour and exchange of vibrational signals between live insects and in playback experiments. Males emitted long and complex calling signals composed of several sections. Female reply was long and always overlapped the end of the male call. The exchange of male and female vibrational signals was a complex and dynamic interaction during which both partners modified their signals according to partner's reply. The duration of female reply was influenced by the duration of the male call to which she was responding, while the duration of male call was influenced by the duration of the previous female reply. Such relationship suggests the role of sexual selection in the evolution of male vibrational signals. [ABSTRACT FROM AUTHOR]

Nymphs of Homalodisca vitripennis are strict xylophages and frequently switch host-plants to obtain a balanced level of nutrients at appropriate tension levels. Associative learning of odors and other semiochemicals may enhance the nymphs’ ability to recognize and locate potential host-plants. We examined whether nymphs could learn to associate a novel olfactory stimulus (vanilla) with a host-plant. Nymphs fed on cowpea plants treated systemically with vanilla extract or on untreated plants. Subsequently, their responses to a pale green target were measured in the presence or absence of vanilla odor. Nymphs were not innately attracted to pale green, and exposure to vanilla odor did not decrease a stereotypical scanning behavior. However, when presented with vanilla odor, significantly more conditioned nymphs selected the target than did control nymphs. [ABSTRACT FROM AUTHOR]

A media for the production of cell cultures from hymenopteran species such as honey bee, Apis mellifera L. (Hymenoptera: Apidae) was developed. Multiple bee cell cultures were produced when using bee larvae and pupae as starting material and modified Hert–Hunter 70 media. Cell culture systems for bees solves an impasse that has hindered efforts to isolate and screen pathogens which may be influencing or causing colony collapse disorder of bees. Multiple life stages of maturing larvae to early pupae were used to successfully establish cell cultures from the tissues of the head, thorax, and abdomen. Multiple cell types were observed which included free-floating suspensions, fibroblast-like, and epithelia-like monolayers. The final culture medium, WH2, was originally developed for hemipterans, Asian citrus psyllid, Diaphorina citri, and leafhopper, Homalodisca vitripennis cell cultures but has been shown to work for a diverse range of insect species such as bees. Bee cell cultures had various doubling times at 21–23°C ranging from 9–15 d. Deformed wing virus was detected in the primary explanted tissues, which tested negative by rt-PCR for Israeli acute paralysis virus (IAPV), Kashmir bee virus, acute bee paralysis virus, and black queen cell virus. Culture inoculation with IAPV from an isolate from Florida field samples, was detectable in cell cultures after two subcultures. Cell culture from hymenoptera species, such as bees, greatly advances the approaches available to the field of study on colony collapse disorders. [ABSTRACT FROM AUTHOR]

Three sowing date trials, each planted with one cultivar, were performed to measure the natural incidence of the Maize rayado fino virus (MRFV). The lowest incidences (1–6%) were obtained at the sowing dates normally practised in the tested regions. Earlier or later sowing dates had higher to much higher incidences (up to 18 and 32%). Two cultivar trials, one with four cultivars and one with eight cultivars, showed significant differences in incidence, ranging from 14.0% in ‘Iniap-160’ to 2.0% in ‘Cadet-2’. In one trial with plots of 1000 m2, the cultivar Iniap-122 was sown at three sowing dates. In each plot, plants that developed MRFV symptoms at the 8–10 leaf stage, at the 12–14 leaf stage and at the emergence of tassels were marked. Marked MRFV-affected plants were compared with non-MRFV-affected plants in their neighbourhood to estimate yield loss due to MRFV. The yield losses at the three sowing dates were 2.5, 1.6 and 4.8%, respectively. It was concluded that the yield loss due to MRFV is quite small provided sowing is restricted to the normal sowing period. [ABSTRACT FROM AUTHOR]

Alder yellows phytoplasma was detected by PCR in Alnus glutinosa trees in the Palatine and Mosel areas of Germany. The restriction profiles obtained by TaqI and AluI digestion of a PCR amplified ribosomal DNA fragment from this phytoplasma and a periwinkle isolate of alder yellows from Italy (ALY) could not be distinguished while elm yellows isolates from Europe and North America led to different fragment patterns. Different restriction profiles for ALY and the German alder phytoplasma were obtained by TruI digestion of a non-ribosomal DNA fragment. Phloem feeding insects were collected from infected alder trees. Phytoplasmas of the elm-yellows group were detected by PCR in psyllids and the leafhopper Oncopsis alni. These pathogens were indistinguishable from the phytoplasma found in alder. Only O. alni was able to transmit the pathogen to healthy alder seedlings. Thus, it is the first insect known to transmit this phytoplasma. This leafhopper could be responsible for the ubiquitous infection of Alnus glutinosa due to its close association with alder and its wide distribution in Europe. [ABSTRACT FROM AUTHOR]

The complete nucleotide sequence of an infectious, insect-transmissible clone of a beet curly top virus isolate originating from Iran (BCTV-I) has been determined. The nucleotide sequence of BCTV-I shows high levels of similarity to the sequences of BCTV strains isolated from North America, and is nearly identical to the CFH strain of BCTV. The symptoms produced by BCTV-I in Nicotiana benthamiana and Beta vulgaris most closely resemble those of the CFH strain and are distinct from the other isolates. The significance of these findings with respect to the possible geographic origins and evolution of BCTV are discussed. [ABSTRACT FROM AUTHOR]

Plant-mediated egg mortality varied greatly for the oligophagous leafhopper, Carneocephala floridana, a common inhabitant of the salt marshes along Florida's Gulf coast. In the laboratory, survivorship from egg to first instar was generally greater on two herbaceous plants. Borrichia frutescens and Salicornia virginica (80 and 81% respectively) than it was on two grasses, Distichlis spicata and Spartina alterniflora (41 and 77% respectively). Although C. floridana laid significantly more eggs per clutch on Sp. alterniflora than on the two herbaceous species, this increase in egg number was offset by the higher mortality of eggs laid on this species. The greatest source of identifiable plant-mediated egg mortality was death due to desiccation of the leaf tissue surrounding the egg clutch. In addition, field experiments in which the four host species were infested with eggs of C. floridana at natural densities consistently yielded higher parasitism rates by two mymarid wasps on the grasses, regardless of the background plants. C. floridana switches host plants seasonally, using the grass species mainly during the winter months, when the herbaceous species experience a substantial dieback. The herbaceous species are nutritionally superior to the two grass species as a food source for C. floridana. C. floridana reared on the herbs produce larger, more fecund, adults than they do on the grasses (Rossi 1991). However, during cold winter snaps the grasses, while less 'attractive', may provide the most abundant nutritional and ovipositional resources available to C. floridana. The results of this study indicate how variable rates of plant-and parasitoid-mediated egg mortality may work synergistically with the interspecific nutritional status of the plants to explain host switching for this insect. [ABSTRACT FROM AUTHOR]

This study investigated the effects of damage by the typhlocybine leafhopper Ossiannilssonola callosa on the physiology of sycamore seedlings. Feeding by 20 adult leafhoppers for four days produced stippling damage of about 10% of total leaf area. Measurements immediately following removal of the leafhoppers showed a 22% decrease in photosynthesis, 25% decrease in daytime rate of water loss and a 34% increase in night-time rate of water loss, probably due to impaired stomatal function. Sixteen days later control of stomatal function was largely regained with rates of photosynthesis similar to the control plants and slightly higher rates of water loss (6.6% day, 18.0% night) attributable to the still-open feeding punctures of the leafhoppers. Daytime SO uptake was similar in damaged and control plants but at night the damaged plants showed a 35% increase in uptake. The hypothesis that leafhopper damage is responsible for this increase is supported by a positive relationship between uptake rate and area of leaf stippled. The physiological effects of leafhopper feeding are greater than the visible damage suggests and the effects are particularly serious when the damage is fresh. Increased rate of air pollutant entry to damaged plants is also a problem, again most marked when damage is fresh. [ABSTRACT FROM AUTHOR]

Copyright of American Potato Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of American Potato Journal is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Potato Research is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Eleven microsatellite markers were developed for the leafhoppers of the genus Aphrodes using shotgun pyrosequencing and will be used to study the genetic diversity, population structure and gene flow within and between species in this genus in order to assess their conservation status. The number of alleles per locus ranged from 3 to 10, while observed and expected heterozygosity values varied from 0.421-1.000 to 0.542-0.876, respectively. Cross-species amplification was successful among the four congeners. [ABSTRACT FROM AUTHOR]

In the present study, a new set of primers of gyrA and gyrB genes of the phytoplasma genome were designed and validated for the successful detection and taxonomic classification of the previously identified phytoplasma strains of 'Candidatus P. asteris' (16SrI-B subgroup) associated with Catharanthus leaf yellows, sesame phyllody and the leafhopper (Hishimonus phycitis). Our results suggested the ability and sensitivity of gyrA and gyrB genes as an alternative molecular marker to identify the Ca. P. asteris strain up to subgroup level associated both with plants and insects. [ABSTRACT FROM AUTHOR]

Phytoplasma suspected symptoms of phyllody, witches’ broom, leaf yellowing, stunting and little leaf were observed in Chrysanthemum morifolium, Bougainvillea glabra, Jasminum sambac and Callistephus chinensis during survey of flower nurseries and experimental ornamental fields at Delhi, Maharashtra, Tamil Nadu and Karnataka from 2014 to 2016. Pleomorphic bodies typical to phytoplasma structures were observed in the phloem sieve elements of ultrathin sections of all the four symptomatic ornamental plants (stem tissue) in transmission electron microscope. Amplification of 1.8 and 1.2 kb phytoplasma DNA products was observed in all the four test plants in PCR assays using universal primer pairs P1/P7 followed by nested primer pair R16F2n/R16R2, respectively. Pairwise sequence comparison, phylogeny and virtual RFLP analysis of 16S rDNA sequences confirmed the association of two phytoplasma subgroups (16SrI-B and 16SrII-D) in four ornamental plant species. ‘Ca. P. aurantifolia’ subgroup D (16SrII-D) was found associated with chrysanthemum phyllody and leaf yellowing at Delhi and Tamil Nadu, bougainvillea little leaf and yellowing at Delhi and Chinese aster phyllody at Bengaluru, Karnataka. However, jasmine little leaf and yellowing at Bengaluru, Karnataka and chrysanthemum stunting at Pune were found to be associated with ‘Ca. P. asteris’ subgroup B-related strains (16SrI-B). The identification of 16SrII-D subgroup phytoplasma infecting bougainvillea and 16SrI-B subgroup infecting jasmine are the new reports to the world. Besides weed species, Cannabis sativa showing witches’ broom in jasmine fields at Bengaluru and Parthenium hysterophorus showing witches’ broom symptoms in chrysanthemum fields at Delhi were identified to be caused by phytoplasma strains classified under subgroups 16SrI-B and 16SrII-D, respectively, by PCR assays and 16Sr DNA sequence comparison analysis. Among the three major leafhopper species identified, only Hishimonas phycitis was identified positive for 16SrI-B and 16SrII-D subgroups of phytoplasmas from chrysanthemum fields at Delhi and jasmine fields at Bengaluru, respectively. The identity of similar phytoplasma strains infecting ornamental species in leafhopper and the weed species in the present study suggested that H. phycitis and weeds may act as potential natural sources for secondary spread of the identified phytoplasma strains. [ABSTRACT FROM AUTHOR]