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12 pages, 1758 KiB

Open AccessArticle

First Report of the Association of the Psyllid Vector Bactericera trigonica (Hemiptera: Triozidae) with ‘Candidatus Liberibacter Solanacearum’ in Italy

by Giorgia Bertinelli, Lorenza Tizzani, Fabio Mosconi, Vincenza Ilardi and Sabrina Bertin

Insects 2024, 15(2), 117; https://doi.org/10.3390/insects15020117 - 06 Feb 2024

Viewed by 900

Abstract

Psyllids, members of the family Triozidae, represent a potential threat to the cultivation of solanaceous and apiaceous crops worldwide, mainly as vectors of the phloem-restricted bacterium ‘Candidatus Liberibacter solanacearum’ (Lso). The Lso haplotypes C, D and E are known to affect apiaceous [...] Read more.

Psyllids, members of the family Triozidae, represent a potential threat to the cultivation of solanaceous and apiaceous crops worldwide, mainly as vectors of the phloem-restricted bacterium ‘Candidatus Liberibacter solanacearum’ (Lso). The Lso haplotypes C, D and E are known to affect apiaceous crops, such as carrot and celery, in several European countries. In Italy, data on the incidence and natural spread of both Lso and psyllids have not been reported so far. In this study, the presence of the vectors was investigated in a main Italian district for carrot production, the “Altopiano del Fucino” area (Central Italy). Both occasional and regular surveys were carried out on a total of five carrot fields and one potato field in 2021 and 2022. Bactericera trigonica (Hodkinson), which is known to efficiently transmit Lso to carrots, was found to be well-established in the area. High levels of population density were recorded in the summer period (more than 100 adult specimens per trap caught every two weeks) and then sharply decreased after the carrot harvest, confirming the strict association of this psyllid species with crop availability. In 2022, 27.5% of the total tested psyllid samples resulted in being positive for Lso haplotypes D and E, the latter being prevalent. This survey revealed, for the first time in Italy, the presence of B. trigonica adults associated with Lso in carrot crops. Although this study was limited to a few fields located in one area, it provided important evidence of the risks for Lso outbreaks and prompted further research to assess the spread and incidence of the disease in apiaceous cultivations in Italy. Full article

(This article belongs to the Special Issue Insect Vectors of Plant Diseases)

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21 pages, 4134 KiB

Open AccessArticle

Comparing Different Sticky Traps to Monitor the Occurrence of Philaenus spumarius and Neophilaenus campestris, Vectors of Xylella fastidiosa, in Different Crops

by Crescenza Dongiovanni, Michele Di Carolo, Giulio Fumarola, Daniele Tauro, Biagio Tedone, Simona Ancona, Valentina Palmisano, Mauro Carrieri and Vincenzo Cavalieri

Insects 2023, 14(9), 777; https://doi.org/10.3390/insects14090777 - 21 Sep 2023

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Abstract

Following the detection of the quarantine bacterium Xylella fastidiosa (Wells et al.) in the Apulia region (southern Italy) and the identification of spittlebugs as the main vector species that contributes to its epidemic spread, monitoring activities have been intensified in an attempt to [...] Read more.

Following the detection of the quarantine bacterium Xylella fastidiosa (Wells et al.) in the Apulia region (southern Italy) and the identification of spittlebugs as the main vector species that contributes to its epidemic spread, monitoring activities have been intensified in an attempt to implement vector control strategies. To date, sweep nets have been the most widely used sampling method to monitor adult spittlebug populations. Field experiments were carried out, during 2018 and 2019, to evaluate the effectiveness of sticky traps in capturing spittlebugs in different woody crops. The attractiveness of different traps was compared: four colored sticky traps (white, red, blue, and yellow), with the yellow sticky traps having three different background patterns (plain yellow, yellow with a black circle pattern, and yellow with a black line pattern). In addition, the efficiency of the yellow sticky traps was evaluated by placing the traps on the ground or hanging them from the canopies in orchards with different spittlebug population densities. Trap catches of Philaenus spumarius (Linnaeus) and Neophilaenus campestris (Fallén) (Hemiptera: Aphrophoridae) were compared with those collected using sweep nets. The two spittlebug species showed a similar response to the colored traps and were mainly attracted to the yellow sticky traps. Captures throughout the adult season indicated that an accurate estimation of the presence and abundance of spittlebugs can be obtained by integrating the two sampling methods. Moreover, sweep nets appeared to be more efficient in collecting adults soon after their emergence, while the use of sticky traps was more efficient in the rest of the adult season when the use of traps can significantly expedite vector monitoring programs. Full article

(This article belongs to the Special Issue Insect Vectors of Plant Diseases)

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16 pages, 1579 KiB

Open AccessArticle

Competition among Flavescence Dorée Phytoplasma Strains in the Experimental Insect Vector Euscelidius variegatus

by Marika Rossi, Luciana Galetto, Nicola Bodino, Jessica Beltramo, Silvia Gamalero, Mattia Pegoraro, Domenico Bosco and Cristina Marzachì

Insects 2023, 14(7), 575; https://doi.org/10.3390/insects14070575 - 23 Jun 2023

Cited by 2 | Viewed by 1135

Abstract

Phytoplasmas are plant pathogenic wall-less bacteria transmitted in a persistent propagative manner by hemipteran insects, mainly belonging to the suborder Auchenorrhyncha (Fulgoromorpha and Cicadomorpha). Flavescence dorée (FD) is a quarantine disease of grapevine, causing great damage to European viticulture and associated with phytoplasmas [...] Read more.

Phytoplasmas are plant pathogenic wall-less bacteria transmitted in a persistent propagative manner by hemipteran insects, mainly belonging to the suborder Auchenorrhyncha (Fulgoromorpha and Cicadomorpha). Flavescence dorée (FD) is a quarantine disease of grapevine, causing great damage to European viticulture and associated with phytoplasmas belonging to 16SrV-C (FD-C) and -D (FD-D) subgroups. FD-C and FD-D strains share similar pathogenicity, but mixed infections are rare in nature. To investigate the competition among FDp strains, specimens of the laboratory vector Euscelidius variegatus (Hemiptera: Cicadellidae) were forced to acquire both phytoplasma haplotypes upon feeding on FD-C- and FD-D-infected plants or after the injection of both strains. The pathogen colonization of insect bodies and heads was monitored with multiplex qPCR, and the efficiencies of phytoplasma transmission were estimated. Single infection, irrespective of strain type, was more frequent than expected, indicating that competition among FD strains occurs. Hypotheses of competition for resources and/or host active sites or the direct antibiosis of one strain against the other are discussed, based on the genetic complexity of FDp populations and on the high genome variability of the FD-D strain. As FD management still mainly relies on insecticides against vectors, the characterization of FDp haplotypes and the description of their epidemiology also have practical implications. Full article

(This article belongs to the Special Issue Insect Vectors of Plant Diseases)

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17 pages, 1724 KiB

Open AccessArticle

Native and Non-Native Bemisia tabaci NAFME Haplotypes Can Be Implicated in Dispersal of Endemic and Introduced Begomoviruses in Oman

by Muhammad Shafiq Shahid, Jorge R. Paredes-Montero, Muhammad Ashfaq, Abdullah M. Al-Sadi and Judith K. Brown

Insects 2023, 14(3), 268; https://doi.org/10.3390/insects14030268 - 08 Mar 2023

Cited by 1 | Viewed by 1430

Abstract

Irrigated agriculture and global trade expansion have facilitated diversification and spread of begomoviruses (Geminiviridae), transmitted by the Bemisia tabaci (Gennadius) cryptic species. Oman is situated on major crossroads between Africa and South Asia, where endemic/native and introduced/exotic begomoviruses occur in agroecosystems. [...] Read more.

Irrigated agriculture and global trade expansion have facilitated diversification and spread of begomoviruses (Geminiviridae), transmitted by the Bemisia tabaci (Gennadius) cryptic species. Oman is situated on major crossroads between Africa and South Asia, where endemic/native and introduced/exotic begomoviruses occur in agroecosystems. The B. tabaci ‘B mitotype’ belongs to the North Africa–Middle East (NAFME) cryptic species, comprising at least eight endemic haplotypes, of which haplotypes 6 and/or 8 are recognized invasives. Prevalence and associations among native and exotic begomoviruses and NAFME haplotypes in Oman were investigated. Nine begomoviral species were identified from B. tabaci infesting crop or wild plant species, with 67% and 33% representing native and exotic species, respectively. Haplotypes 2, 3, and 5 represented 31%, 3%, and 66% of the B. tabaci population, respectively. Logistic regression and correspondence analyses predicted ‘strong’- and ‘close’ virus–vector associations involving haplotypes 5 and 2 and the exotic chili leaf curl virus (ChiLCV) and endemic tomato yellow leaf curl virus-OM, respectively. Patterns favor a hypothesis of relaxed virus–vector specificity between an endemic haplotype and the introduced ChiLCV, whereas the endemic co-evolved TYLCV-OM and haplotype 2 virus–vector relationship was reinforced. Thus, in Oman, at least one native haplotype can facilitate the spread of endemic and introduced begomoviruses. Full article

(This article belongs to the Special Issue Insect Vectors of Plant Diseases)

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13 pages, 1687 KiB

Open AccessArticle

Cicadomorpha Community (Hemiptera: Auchenorrhyncha) in Portuguese Vineyards with Notes of Potential Vectors of Xylella fastidiosa

by Isabel Rodrigues, Maria Teresa Rebelo, Paula Baptista and José Alberto Pereira

Insects 2023, 14(3), 251; https://doi.org/10.3390/insects14030251 - 02 Mar 2023

Cited by 3 | Viewed by 1587

Abstract

Cicadomorpha (Hemiptera) insects are currently responsible for a growing negative impact on the agricultural economy due to their ability to directly damage crops or through the capacity to act as vectors for plant pathogens. The phytopathogenic bacterium Xylella fastidiosa, the causal agent [...] Read more.

Cicadomorpha (Hemiptera) insects are currently responsible for a growing negative impact on the agricultural economy due to their ability to directly damage crops or through the capacity to act as vectors for plant pathogens. The phytopathogenic bacterium Xylella fastidiosa, the causal agent of Pierce’s disease in vineyards, is exclusively transmitted by insects of this infraorder. Therefore, knowledge of the Cicadomorpha species and understanding their biology and ecology is crucial. In this work, in 2018 and 2019, the canopy and inter-row vegetation of 35 vineyards distributed in mainland Portugal were sampled to investigate species composition, richness, and diversity of the Cicadomorpha community, with a special focus given to vectors and potential vectors of X. fastidiosa. A total of 11,834 individuals were collected, 3003 in 2018 and 8831 in 2019. Of the 81 species/morphospecies identified, only five are considered vectors or potential vectors of this pathogen, namely, Cicadella viridis (Linnaeus, 1758), Philaenus spumarius (Linnaeus, 1758), Neophilaenus campestris (Fallén, 1805), Lepyronia coleoptrata (Linnaeus, 1758), and N. lineatus (Linnaeus, 1758). Cicadella viridis was the most abundant xylem sap feeder, followed by P. spumarius. In addition, Cicadomorpha that cause direct damage to vines and vectors of grapevine yellows’ phytoplasmas were also collected and identified in the sampled vineyards. The results suggested that vectors and potential vectors of X. fastidiosa and a large proportion of the population of Cicadomorpha have a positive correction with inter-row vegetation. Full article

(This article belongs to the Special Issue Insect Vectors of Plant Diseases)

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13 pages, 4372 KiB

Open AccessArticle

Potentially Suitable Geographical Area for Monochamus alternatus under Current and Future Climatic Scenarios Based on Optimized MaxEnt Model

by Ruihe Gao, Lei Liu, Lijuan Zhao and Shaopeng Cui

Insects 2023, 14(2), 182; https://doi.org/10.3390/insects14020182 - 13 Feb 2023

Cited by 6 | Viewed by 1928

Abstract

M. alternatus is considered to be an important and effective insect vector for the spread of the important international forest quarantine pest, Bursaphelenchus xylophilus. The precise determination of potential suitable areas of M. alternatus is essential to monitor, prevent, and control M. [...] Read more.

M. alternatus is considered to be an important and effective insect vector for the spread of the important international forest quarantine pest, Bursaphelenchus xylophilus. The precise determination of potential suitable areas of M. alternatus is essential to monitor, prevent, and control M. alternatus worldwide. According to the distribution points and climatic variables, the optimized MaxEnt model and ArcGIS were used to predict the current and future potentially suitable areas of M. alternatus worldwide. The optimized MaxEnt model parameters were set as feature combination (FC) = LQHP and β = 1.5, which were determined by the values of AUC_diff, OR₁₀, and ΔAICc. Bio2, Bio6, Bio10, Bio12, and Bio14 were the dominant bioclimatic variables affecting the distribution of M. alternatus. Under the current climate conditions, the potentially suitable habitats of M. alternatus were distributed across all continents except Antarctica, accounting for 4.17% of the Earth’s total land area. Under future climate scenarios, the potentially suitable habitats of M. alternatus increased significantly, spreading to a global scale. The results of this study could provide a theoretical basis for the risk analysis of the global distribution and dispersal of M. alternatus as well as the precise monitoring and prevention of this beetle. Full article

(This article belongs to the Special Issue Insect Vectors of Plant Diseases)

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15 pages, 4813 KiB

Open AccessArticle

Aphrophoridae as Potential Vectors of Xylella fastidiosa in Tunisia

by Sonia Boukhris-Bouhachem, Rebha Souissi, Raied Abou Kubaa, Maroun El Moujabber and Vladimir Gnezdilov

Insects 2023, 14(2), 119; https://doi.org/10.3390/insects14020119 - 24 Jan 2023

Cited by 2 | Viewed by 2201

Abstract

The present study is an update on the situation of potential vectors of Xylella fastidiosa in Tunisia. Investigations in nine Tunisian regions (Nabeul, Bizerte, Béja, Jendouba, Zaghouan, Kairouan, Ben Arous, Tunis and Manouba) from 2018 to 2021 allowed for the observation of 3758 [...] Read more.

The present study is an update on the situation of potential vectors of Xylella fastidiosa in Tunisia. Investigations in nine Tunisian regions (Nabeul, Bizerte, Béja, Jendouba, Zaghouan, Kairouan, Ben Arous, Tunis and Manouba) from 2018 to 2021 allowed for the observation of 3758 Aphrophoridae among a total of 9702 Auchenorrhyncha individuals collected by sweep net. Four Aphrophoridae species were identified with Philaenus tesselatus as most abundant (62%), followed by Neophilaenus campestris (28%), Neophilaenus lineatus (5%) and Philaenus maghresignus (5%). Aphrophoridae individuals were found to be particularly abundant in both forests of Nabeul and Jendouba, secondarily in olive groves and dry grassland. Furthermore, their distribution on weed hosts was followed in these two regions where nymphs and adults are widely distributed. P. tesselatus appears to be the most abundant species as determined either by conventional sweep netting for adults or by plant sampling on Sonchus, Smyrnium, Cirsium, Rumex, Polygonum and Picris for nymphs. Limited numbers of adults of P. maghresignus were detected by sweep netting, while nymphs of this species were found on Asphodelus microcarpus only. N. campestris was found in high numbers on plants belonging to the Poaceae family in forests, dry grassland and olive groves whereas N. lineatus occurred on herbs under or near olive trees and in dry grasslands. Full article

(This article belongs to the Special Issue Insect Vectors of Plant Diseases)

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16 pages, 2063 KiB

Open AccessArticle

Efficacy of Conventional and Organic Insecticides against Scaphoideus titanus: Field and Semi-Field Trials

by Stefan Cristian Prazaru, Lisa D’Ambrogio, Martina Dal Cero, Mirko Rasera, Giovanni Cenedese, Enea Guerrieri, Marika Pavasini, Nicola Mori, Francesco Pavan and Carlo Duso

Insects 2023, 14(2), 101; https://doi.org/10.3390/insects14020101 - 17 Jan 2023

Cited by 3 | Viewed by 2706

Abstract

Scaphoideus titanus is the main vector of phytoplasmas associated with Flavescence dorée (FD), one of the most serious threats to viticulture in many European countries. To minimize the spread of this disease, mandatory control measures against S. titanus were decided in Europe. In [...] Read more.

Scaphoideus titanus is the main vector of phytoplasmas associated with Flavescence dorée (FD), one of the most serious threats to viticulture in many European countries. To minimize the spread of this disease, mandatory control measures against S. titanus were decided in Europe. In the 1990s, the repeated application of insecticides (mainly organophosphates) proved to be an effective measure to control the vector and the related disease in north-eastern Italy. These insecticides and most of the neonicotinoids were recently banned from European viticulture. Serious FD issues detected in the recent years in northern Italy could be related to the use of less effective insecticides. Trials aimed at evaluating the efficacy of the most used conventional and organic insecticides in the control of S. titanus have been performed in semi-field and field conditions to test this hypothesis. In efficacy trials, carried out in four vineyards, etofenprox and deltamethrin proved to be the best conventional insecticides, while pyrethrins were the most impactful among organic insecticides. Insecticide residual activity was evaluated in semi-field and field conditions. Acrinathrin showed the most significant residual effects in both conditions. In semi-field trials, most of the pyrethroids were associated with good results in terms of residual activity. However, these effects declined in field conditions, probably due to high temperatures. Organic insecticides showed poor results in terms of residual efficacy. Implications of these results in the context of Integrated Pest Management in conventional and organic viticulture are discussed. Full article

(This article belongs to the Special Issue Insect Vectors of Plant Diseases)

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16 pages, 2555 KiB

Open AccessArticle

Rickettsia Infection Benefits Its Whitefly Hosts by Manipulating Their Nutrition and Defense

by Ze-Yun Fan, Yuan Liu, Zi-Qi He, Qin Wen, Xin-Yi Chen, Muhammad Musa Khan, Mohamed Osman, Nasser Said Mandour and Bao-Li Qiu

Insects 2022, 13(12), 1161; https://doi.org/10.3390/insects13121161 - 15 Dec 2022

Cited by 4 | Viewed by 2057

Abstract

Endosymbionts play an essential role in the biology, physiology and immunity of insects. Many insects, including the whitefly Bemisia tabaci, are infected with the facultative endosymbiont Rickettsia. However, the mutualism between Rickettsia and its whitefly host remains unclear. This study investigated the [...] Read more.

Endosymbionts play an essential role in the biology, physiology and immunity of insects. Many insects, including the whitefly Bemisia tabaci, are infected with the facultative endosymbiont Rickettsia. However, the mutualism between Rickettsia and its whitefly host remains unclear. This study investigated the biological and physiological benefits of Rickettsia infection to B. tabaci. Results revealed that infection of Rickettsia increased the fertility, the survival rate from nymph to adult and the number of female whiteflies. In addition, this facilitation caused a significant reduction in nymphal developmental duration but did not affect percentage rate of egg hatching. Rickettsia infected B. tabaci had significantly higher glycogen, soluble sugar and trehalose contents than Rickettsia negative B. tabaci individuals. Rickettsia also improved the immunity of its whitefly hosts. Rickettsia infested B. tabaci had lower mortality rates and higher semi-lethal concentrations (LC₅₀) when exposed to the fungus Akanthomyces attenuatus and the insecticides imidacloprid and spirotetramat. The percentage of parasitism by Encarsia formosa was also reduced by Rickettsia infection. Overall, Rickettsia infection benefits B. tabaci by improving the nutritional composition of its host, and also protects B. tabaci by enhancing its resistance towards insecticides (imidacloprid and spirotetramat), entomopathogenic fungi (A. attenuatus) and its main parasitoid (E. formosa); all of which could significantly impact on current management strategies. Full article

(This article belongs to the Special Issue Insect Vectors of Plant Diseases)

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15 pages, 2847 KiB

Open AccessArticle

Molecular Detection of Pentastiridius leporinus, the Main Vector of the Syndrome ‘Basses Richesses’ in Sugar Beet

by René Pfitzer, Mark Varrelmann, Georgia Hesse and Omid Eini

Insects 2022, 13(11), 992; https://doi.org/10.3390/insects13110992 - 28 Oct 2022

Cited by 1 | Viewed by 2155

Abstract

Monitoring of Pentastiridius leporinus (Hemiptera: Auchenorrhyncha: Cixiidae), representing the main vector of the syndrome ‘basses richesses’ (SBR) disease in sugar beet is based on morphological identification. However, two other cixiid species, Reptalus quinquecostatus and Hyalesthes obsoletus with similar external characters are known to [...] Read more.

Monitoring of Pentastiridius leporinus (Hemiptera: Auchenorrhyncha: Cixiidae), representing the main vector of the syndrome ‘basses richesses’ (SBR) disease in sugar beet is based on morphological identification. However, two other cixiid species, Reptalus quinquecostatus and Hyalesthes obsoletus with similar external characters are known to appear in sugar beet fields and are challenging to be distinguished from P. leporinus. We present a PCR-based method for species-specific detection of both male and female P. leporinus, directly after sweep net collection or after up to 18 months long term storage on sticky traps. Two methods of DNA template preparation, based on a commercial extraction kit or on simple grinding in phosphate-buffered saline (PBS) were compared. The latter method was also established for eggs and all five nymphal instars of P. leporinus from a rearing. Furthermore, in silico primer analysis showed that all Auchenorrhyncha species including far related species reported from sugar beet fields can be differentiated from P. leporinus. This was PCR-confirmed for the most common Auchenorrhyncha species from different German sugar beet fields. Sequence analysis of the P. leporinus mitochondrial cytochrome oxidase I gene (COI) amplicon showed a close relationship to COI from P. beieri but separated from the Reptalus and Hyalesthes species which are grouped into the same family Cixiidae. We present a sensitive, cost- and time-saving PCR-based method for reliable and specific detection of eggs and all nymphal instars, as well as male and female P. leporinus, after different methods of planthopper collection and template DNA template preparation that can be used in large scale monitoring assays. Full article

(This article belongs to the Special Issue Insect Vectors of Plant Diseases)

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16 pages, 1244 KiB

Open AccessArticle

Survey of Candidatus Liberibacter Solanacearum and Its Associated Vectors in Potato Crop in Spain

by M. Carmen Asensio-S.-Manzanera, Yolanda Santiago-Calvo, José Luis Palomo-Gómez, Raquel Marquínez-Ramírez, Saskia Bastin, Eva María García-Méndez, Estrella Hernández-Suárez and Felipe Siverio-de-la-Rosa

Insects 2022, 13(10), 964; https://doi.org/10.3390/insects13100964 - 21 Oct 2022

Cited by 3 | Viewed by 1324

Abstract

‘Candidatus Liberibacter solanacearum’ (CaLsol), the etiological agent of potato zebra chip (ZC), is transmitted to potato plants by the psyllid Bactericera cockerelli (Šulc, 1909) in North and Central America and New Zealand. The risk of the dispersion of ZC in Spain depends [...] Read more.

‘Candidatus Liberibacter solanacearum’ (CaLsol), the etiological agent of potato zebra chip (ZC), is transmitted to potato plants by the psyllid Bactericera cockerelli (Šulc, 1909) in North and Central America and New Zealand. The risk of the dispersion of ZC in Spain depends on the presence of an efficient vector. This work studies the presence and abundance of ZC symptoms and CaLsol in potato plants, as well as the presence and abundance of psyllid species associated with potato crops in the main producing areas in Spain. Eighty-eight plots were surveyed punctually to detect ZC symptoms and psyllid species in the main potato-producing areas. Furthermore, fourteen potato plots were surveyed by different sampling methods during the cropping season to detect psyllid species from 2016 to 2018. Very few symptomatic and CaLsol-positive plants were detected in Mainland Spain, and any positive plant was detected in the Canary Islands. Most of the adult psyllids captured were identified as Bactericera nigricornis (Foerster, 1848), and some of them as Bactericera trigonica, but no B. cockerelli was detected. B. nigricornis was found widely distributed in the northern half of the Iberian Peninsula; however, this psyllid does not seem sufficient to pose a threat to potato production, due to the scarce number of specimens and because the frequency of B. nigricornis specimens that were CaLsol+ was very low. Full article

(This article belongs to the Special Issue Insect Vectors of Plant Diseases)

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13 pages, 1523 KiB

Open AccessArticle

Mitochondrial Genetic Diversity of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Associated with Cassava in Lao PDR

by Ana M. Leiva, Khonesavanh Chittarath, Diana Lopez-Alvarez, Pinkham Vongphachanh, Maria Isabel Gomez, Somkhit Sengsay, Xiao-Wei Wang, Rafael Rodriguez, Jonathan Newby and Wilmer J. Cuellar

Insects 2022, 13(10), 861; https://doi.org/10.3390/insects13100861 - 22 Sep 2022

Cited by 4 | Viewed by 2251

Abstract

Cassava Mosaic Disease (CMD) caused by Sri Lankan cassava mosaic virus (SLCMV), has rapidly spread in Southeast Asia (SEA) since 2016. Recently it has been documented in Lao PDR. Previous reports have identified whitefly species of B. tabaci as potential vectors of CMD [...] Read more.

Cassava Mosaic Disease (CMD) caused by Sri Lankan cassava mosaic virus (SLCMV), has rapidly spread in Southeast Asia (SEA) since 2016. Recently it has been documented in Lao PDR. Previous reports have identified whitefly species of B. tabaci as potential vectors of CMD in SEA, but their occurrence and distribution in cassava fields is not well known. We conducted a countrywide survey in Lao PDR for adult whiteflies in cassava fields, and determined the abundance and genetic diversity of the B. tabaci species complex using mitochondrial cytochrome oxidase I (mtCOI) sequencing. In order to expedite the process, PCR amplifications were performed directly on whitefly adults without DNA extraction, and mtCOI sequences obtained using nanopore portable-sequencing technology. Low whitefly abundances and two cryptic species of the B. tabaci complex, Asia II 1 and Asia II 6, were identified. This is the first work on abundance and genetic identification of whiteflies associated with cassava in Lao PDR. This study indicates currently only a secondary role for Asia II in spreading CMD or as a pest. Routine monitoring and transmission studies on Asia II 6 should be carried out to establish its potential role as a vector of SLCMV in this region. Full article

(This article belongs to the Special Issue Insect Vectors of Plant Diseases)

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18 pages, 2883 KiB

Open AccessArticle

Turnip Mosaic Virus Infection Differentially Modifies Cabbage Aphid Probing Behavior in Spring and Winter Oilseed Rape (Brassica napus)

by Zhong-Ping Hao, Lei Sheng, Zeng-Bei Feng, Wei-Xin Fei and Shu-Min Hou

Insects 2022, 13(9), 791; https://doi.org/10.3390/insects13090791 - 31 Aug 2022

Cited by 3 | Viewed by 1710

Abstract

Direct and indirect effects of plant virus infection on vector behavior have been discovered to improve virus transmission efficiency, but the impact of plant cultivars in virus–vector–plant interactions has received little attention. Electropenetrography (EPG) allows real-time tracking and quantification of stylet penetration behaviors, [...] Read more.

Direct and indirect effects of plant virus infection on vector behavior have been discovered to improve virus transmission efficiency, but the impact of plant cultivars in virus–vector–plant interactions has received little attention. Electropenetrography (EPG) allows real-time tracking and quantification of stylet penetration behaviors, pathogen transmission, and plant resistance mechanisms. Quantitative probing behaviors on a spring oilseed rape cultivar, ‘Xinyou17’, and a winter oilseed rape cultivar, ‘Zheping4’, were investigated using EPG to compare turnip mosaic virus (TuMV) regulation of cabbage aphid probing behavior. Results for indirect effects showed that compared to mock-inoculated plants, cabbage aphids on infected plants increased brief probing frequency, cell penetration frequency, intracellular probing time, and decreased time to first probe and pathway time, potentially promoting viral acquisition. TuMV also directly influences aphid probing behavior. Viruliferous aphids had reduced pathway time, increased cell penetration frequency, increased intracellular probing time, increased salivation frequency, and ingested less sap than non-viruliferous aphids, primed for viral infection. Although oilseed rape cultivars can also influence aphid behavior, the main effect of cultivars was not significant on TuMV-infected plants. Full article

(This article belongs to the Special Issue Insect Vectors of Plant Diseases)

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7 pages, 679 KiB

Open AccessBrief Report

Tomato Leaf Curl New Delhi Virus Spain Strain Is Not Transmitted by Trialeurodes vaporariorum and Is Inefficiently Transmitted by Bemisia tabaci Mediterranean between Zucchini and the Wild Cucurbit Ecballium elaterium

by Alessia Farina, Carmelo Rapisarda, Elvira Fiallo-Olivé and Jesús Navas-Castillo

Insects 2023, 14(4), 384; https://doi.org/10.3390/insects14040384 - 15 Apr 2023

Cited by 1 | Viewed by 1493

Abstract

Tomato leaf curl New Delhi virus (ToLCNDV) is a bipartite begomovirus (genus Begomovirus, family Geminiviridae) persistently transmitted, as with all other begomoviruses, by whiteflies (Hemiptera: Aleyrodidae) of the Bemisia tabaci cryptic species complex. The virus, originally from the Indian subcontinent, was [...] Read more.

Tomato leaf curl New Delhi virus (ToLCNDV) is a bipartite begomovirus (genus Begomovirus, family Geminiviridae) persistently transmitted, as with all other begomoviruses, by whiteflies (Hemiptera: Aleyrodidae) of the Bemisia tabaci cryptic species complex. The virus, originally from the Indian subcontinent, was recently introduced in the Mediterranean basin, where it is currently a major concern for protected and open-field horticulture. The Mediterranean ToLCNDV isolates belong to a novel strain named “Spain strain” (ToLCNDV-ES), which infects zucchini and other cucurbit crops but is poorly adapted to tomato. Recently, it has been reported that another whitefly, Trialeurodes vaporariorum, is able to transmit an isolate of ToLCNDV from India which infects the chayote plant, a cucurbit. The present work aimed to clarify some aspects of whitefly transmission of ToLCNDV-ES. It was shown that T. vaporariorum is not able to transmit ToLCNDV-ES between zucchini plants. In addition, Ecballium elaterium may not act as a relevant reservoir for this virus strain in the Mediterranean basin, as B. tabaci Mediterranean (MED), the most prevalent species of the complex in the region, is not an efficient vector of this begomovirus between cultivated zucchini and wild E. elaterium plants. Full article

(This article belongs to the Special Issue Insect Vectors of Plant Diseases)

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