Search Results (385)

The occurrence of the invasive Orange Spiny Whitefly (Aleurocanthus spiniferus) has expanded rapidly in Italy, prompting responses from both native and unintentionally introduced natural enemies. Through field monitoring, morpho-molecular identification, and phenological analysis, a multi-species parasitoid complex acting on this pest was revealed. In addition to the predominant activity of Eretmocerus iulii, this study reports the first European detection of Encarsia smithi, genetically confirmed as belonging to haplogroup I, a lineage previously associated with A. spiniferus in Asia. Occasional parasitization by Cales noacki was also observed. Seasonal patterns suggest a possible ecological complementarity between Er. iulii and E. smithi, which may contribute to the suppression of A. spiniferus populations. Although climatic variables showed weak correlations with infestation or parasitism rates, a slight positive relationship was observed between rainfall and whitefly abundance. The increasing biocenotic complexity, reflected by the diversity and interactions among parasitoid species, indicates an emerging ecological balance. These findings underscore the potential role of unintentional biological control in supporting agroecosystem resilience. Full article

Orange spiny whitefly (Aleurocanthus spiniferus Quaintance) is a major pest with economic significance to tea plants, as both nymphs and adults suck plant sap and contribute to the development of tea sooty mold. The occurrence of this pest varies considerably among different tea cultivars, even within the same plantation. This study aims to characterize the bioactive constituents of tea volatiles mediating A. spiniferus host selection, and leverage these semiochemicals to develop effective field trapping systems. Through field investigations and Y-tube olfactometer tests, we identified two highly preferred tea cultivars (‘Huangjinya’ and ‘Fuding white tea’) and two cultivars (‘Baiye No. 1’ and ‘Longjing 43’) that were not preferred. Behavioral assays and gas chromatography-mass spectrometry (GC-MS) analysis revealed four attractive compounds [hexanol, (E)-2-hexenal, linalool, and (E,E)-α-farnesene] and two repellent compounds [nonanal and (Z)-3-hexenol] in the volatile emissions of the four cultivars. A hexane solution (10 µL) of nonanol, (Z)-3-hexenol, linalool, and (E,E)-α-farnesene at a concentration of 100 µg/µL was able to elicit an obvious electrophysiological (EAG) response. In field trials, the synergistic bait trap equipped with two types of attractants, 500 µL of hexane solution of the mixture of linalool and (E,E)-α-farnesene (3:1, v/v), and the mixture of linalool and (Z)-3-hexenol (3:1, v/v) at the concentration of 100 μg/μL, showed significantly higher attractant efficacy and selectivity. Overall, this study indicates that tea volatiles play a crucial role in the host selection of A. spiniferus, and the synthetic mixtures of tea volatiles have the potential to be developed as commercial plant-based attractants for adult A. spiniferus. This study contributes to the development of sustainable, environmentally friendly management strategies for a pest that is challenging to prevent and control. Full article

Common bean (Phaseolus vulgaris L.), the world’s most widely grown legume crop, is not only of great commercial importance but is also a vital smallholder crop in low-to-medium-income countries. In sub-Saharan Africa common bean provides consumers with a major proportion of their dietary protein and micronutrients. However, productivity is constrained by viruses, particularly those vectored by aphids and whiteflies, and problems are further compounded by seed-borne transmission. We describe common bean’s major viral threats including the aphid-transmitted RNA viruses bean common mosaic virus and bean common mosaic necrosis virus, and the whitefly-transmitted begomoviruses bean golden mosaic virus and bean golden yellow mosaic virus and discuss how high-throughput sequencing is revealing emerging threats. We discuss how recent work on indirect and direct viral ‘manipulation’ of vector behaviour is influencing modelling of viral epidemics. Viral extended phenotypes also modify legume interactions with beneficial organisms including root-associated microbes, pollinators and the natural enemies of vectors. While problems with common bean tissue culture have constrained transgenic and gene editing approaches to crop protection, topical application of double-stranded RNA molecules could provide a practical protection system compatible with the wide diversity of common bean lines grown in sub-Saharan Africa. Full article

Bemisia tabaci is a major pest of open-field melons in Mediterranean regions. Combining several species of natural enemies can improve pest control but it can give undesirable results when the species engage in antagonistic interactions. This study evaluated the effectiveness of Deraeocoris serenus, Orius laevigatus, and Eretmocerus eremicus as biological control agents and the interactions among the species. This was assessed with the presence–absence of all three species combined in a full-factorial assay. Each microcosm consisted of a melon plant grown in a 5 L pot enclosed in fine mesh, with each of the eight treatments replicated four times. Whiteflies were counted on three leaves per plant, and natural enemies were counted on the whole plants over six weeks. Basal leaves were taken to the laboratory and observed for the emergence of parasitoids. All three natural enemies independently significantly reduced whitefly numbers. Deraeocoris serenus was the most effective biocontrol agent, achieving whitefly reductions of more than 100-fold compared to the control. In contrast, O. laevigatus and E. eremicus achieved reductions of approximately 2.4-fold and 3.6-fold, respectively. No additive or synergistic effects in whitefly control were observed when two or more natural enemies were combined. Deraeocoris serenus and O. laevigatus were found to engage in mutual antagonistic interactions, and these two predators also interfered with the parasitoid. In addition, E. eremicus was also found to interfere with D. serenus. Understanding such interactions is essential for optimizing the management of natural enemies and improving biological pest control. Full article

Bemisia tabaci (Aleyrodidae family) is one of the most damaging pests of numerous crops worldwide. Insecticides, namely pyrethroids and organophosphates, have long been the primary control tools against this pest, resulting in several resistance cases. In Tunisia, the two most damaging biotypes of B. tabaci, MEAM1-B and MED-Q, are sympatric, and more concerns about developing resistance keep rising due to the extensive use of insecticides. Here, we aimed to elucidate the molecular mechanism of resistance to pyrethroids and organophosphorus insecticides in two Tunisian populations of B. tabaci, collected respectively on Capsicum annuum and Lantana camara, and then determine the bacterial community associated with insecticide resistance and susceptible biotypes based on 16S rRNA Illumina sequencing. The results showed that the population collected on Capsicum annuum belonged to the MEAM1-B biotype with an insecticide resistance profile. In contrast, the population collected on the Lantana camara belonged to the MED-Q biotype with a sensitive profile. The bacterial communities of the two biotypes were predominantly structured by the Proteobacteria phylum and three genera, including Candidatus Portiera, the secondary facultative symbiont, and Hamiltonella, which were unevenly distributed between the two biotopes. Our results provide the first evidence for insecticide resistance alleles in Tunisian MEAM1-B populations and suggest an association between bacterial community composition within susceptible biotypes and insecticide resistance. Full article

The whitefly Bemisia tabaci (Hemiptera: Aleyrodoidea) causes direct feeding damage to crop plants and transmits pathogenic plant viruses, thereby threatening global food security. Although whitefly-infecting RNA viruses are known and proposed as biocontrol agents, no insect DNA virus has been found in any member of Aleyrodoidea. Using rolling circle amplification (RCA) of viral DNA from whiteflies collected from crop fields in Morocco, followed by Illumina sequencing of the RCA products, we found a novel insect single-stranded (ss) DNA parvovirus (family Parvoviridae) in addition to plant ssDNA geminiviruses transmitted by whiteflies. Based on its genome organization with inverted terminal repeats and evolutionarily conserved proteins mediating viral DNA replication (NS1/Rep) and encapsidation (VP), encoded on the forward and reverse strands, respectively, we named this virus Bemisia tabaci ambidensovirus (BtaDV) and classified it as a founding member of a new genus within the subfamily Densovirinae. This subfamily also contains three distinct genera of ambisense densoviruses of other hemipteran insects (Aphidoidea, Coccoidea, and Psylloidea). Furthermore, we provide evidence for the genetic variants of BtaDV circulating in whitefly populations and for its partial sequences integrated into the B. tabaci genome, with one integrant locus potentially expressing a fusion protein composed of viral Rep endonuclease and host DNA-binding domains. This suggests a long-term virus-host interaction and neofunctionalization of BtaDV-derived endogenous viral elements. Full article

This paper describes a new species of extinct whitefly in the genus Gregorites Drohojowska & Szwedo, 2024, from the family Aleyrodidae. This species has been identified based on an inclusion in Eocene Baltic amber. This represents the eighth documented species of the genus and contributes new data to our knowledge of the disparity and taxonomic diversity of whiteflies in Eocene Baltic amber. The discovery of a further Gregorites species, previously known only from succinite on the western coast of Jutland, raises questions about the amberiferous deposits, their geology and history, and on palaeodistributions of the whiteflies. These are briefly reviewed and discussed. Full article

Tomato (Solanum lycopersicum) is an essential vegetable crop cultivated worldwide, but its production is highly vulnerable to tomato yellow leaf curl disease (TYLCD), which is transmitted by whiteflies (Bemisia tabaci). Management strategies typically focus on controlling either the virus or its vector. This study evaluates the effectiveness of multi-disease and insect-resistant tomato lines, developed by the World Vegetable Center (WorldVeg), which integrate Ty-1/Ty-3 genes for virus resistance and WF2-10 and WF3-09 genes for whitefly resistance. Virus accumulation, whitefly settling behavior, and adult mortality were assessed among multi-resistant lines, a Ty-resistant line, a whitefly-resistant line, and a susceptible check using preference bioassays, controlled inoculation experiments, and acylsugar quantification. Multi-resistant lines exhibited significantly higher acylsugar concentrations, reduced whitefly preference for settling, and increased whitefly adult mortality. Additionally, these lines displayed less severe disease symptoms and lower virus accumulation over time than Ty-resistant, whitefly-resistant, and susceptible controls. These findings highlight the superior efficacy of combined virus and vector resistance in mitigating tomato yellow leaf curl Thailand virus (TYLCTHV) transmission. This research underscores the importance of integrated genetic resistance as a key element of sustainable integrated pest management strategies, offering an environmentally friendly solution for safeguarding global tomato production. Full article

A dearth of knowledge exists on identifying the begomoviruses and distributing cassava mosaic viruses across key cassava-growing regions of Sierra Leone. The study aimed to identify and map the distribution of cassava mosaic disease (CMD)-associated viruses in farmers’ fields in Sierra Leone. Cassava (Manihot esculenta Crantz) leaf samples were collected in 109 smallholder farms during a geo-referenced survey conducted from 10th May to 5th June 2024. Molecular diagnostics were carried out to identify the viral strains associated with CMD. Findings revealed that infection by stem cutting was more predominant in the south, east, north, and northwest regions than in the west region. In contrast, infection by whitefly was predominant in the west, north, and northwest regions. PCR screening of 426 samples coupled with sequence analysis revealed the presence of African cassava mosaic-like (ACMV-like) viruses, and East African cassava mosaic-like (EACMV-like) viruses as single infections at 78.1% and 1.3%, respectively. Co-infections of ACMV-like and EACMV-like viruses were detected in 20.6% of the tested samples. In addition, 70.6% of the samples positive for EACMV-like virus (single and mixed infections) were found to be positive for East African cassava mosaic Cameroon virus (EACMCMV). The ACMV and co-infection of ACMV and EACMV viruses were present in all regions, while EACMCV was detected in all regions except the western area. The results indicate more prevalence of the EACMCMV variant in Sierra Leone. This study suggests utilization of participatory surveillance and good agronomic practices to manage CMD in Sierra Leone. Full article

A mutation affecting eye color was discovered in Macrolophus pygmaeus (Rambur) (Hemiptera: Miridae). This species is an important biological control agent used to manage whiteflies and other arthropod pests in greenhouse crops. Typically, these predators exhibit a dark eye coloration, ranging from garnet to black. However, individuals with bright red eyes have been identified within wild populations, making them easily distinguishable. The objective of this study was to study the mode of inheritance of the red eye color mutation observed. Additionally, a comparative analysis of key biological traits was conducted between individuals carrying the mutation and those from a wild-type population. From these specimens, a population carrying this eye color mutation, referred to as ruby, was established. Genetic analyses revealed that the red coloration is controlled by a single recessive allele located on an autosomal chromosome. Red-eyed individuals exhibited superior performance in biological traits, including greater body size in both males and females, as well as increased fecundity and longevity in females. The utilization of this red-eyed variant could be valuable as a visual marker in ecological and biological studies of population dynamics. Full article

Insects and their endosymbionts have a close mutualistic relationship. However, the precise nature of the bacterial endosymbiont-mediated interaction between host plants and whitefly Bemisia tabaci MEAM1 is still unclear. In the present study, six populations of Bemisia tabaci MEAM1 sharing the same genetic background were established by rearing insects for ten generations on different host plants, including poinsettia, cabbage, cotton, tomato, and tobacco, and an additional population was reared on cotton and treated with antibiotics. The physiological and nutritional traits of the insects were found to be dependent on the host plant on which they had been reared. Systematic analysis was conducted on the endosymbiont titers, the amino acid molecules and contents, as well as developmental and oviposition changes in the MEAM1 populations reared on each host plant tested. The results indicate that B. tabaci contained the primary symbiont Portiera and the secondary symbionts Hamiltonella and Rickettsia. In addition, the titer of endosymbiotic bacteria in females is higher than that in males. Among the MEAM1 populations reared on each host plant, the variation pattern of Portiera titer generally corresponded with changes in biological characteristics (body length, weight and fecundity) and AA contents. This suggests that changes in the amino acid contents and biological characteristics of different B. tabaci populations may be due to changes in the Portiera content and the differences in the nutrition of the host plants themselves. Our findings were further confirmed by the reduction in Portiera with antibiotic treatment. The amino acids, body size, body weight, and fecundity of B. tabaci were all reduced with the decrease in the Portiera titer after antibiotic treatment. In summary, our research revealed that host plants can affect the content of symbiotic bacteria, particularly Portiera, and subsequently affect the nutrition (i.e., the essential amino acids content) of host insects, thus changing their biological characteristics. Full article

The whitefly, Bemisia tabaci, is a complex of cryptic species that is a significant pest of different legume hosts that inhabits various regions worldwide with diverse climates and characteristics. Its adaptability is often facilitated by the insect’s microbiome, which can contribute to both the metabolism of host plant secondary compounds and insecticide resistance. The most relevant biotypes in Brazil are Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED), because of their ability to damage different hosts. Although MEAM1 is the prevalent species in Brazil, MED has great potential to spread, and there is little current knowledge about the biology of this biotype in the country. Therefore, the objective of this study was to evaluate the development and viability of MED on two legumes, soybean and common bean, alongside cotton, bell pepper, and tomato, at temperatures of 20 °C, 23 °C, 26 °C, 29 °C, 32 °C, and 35 °C and characterize the composition of its endosymbionts. Temperatures between 23 °C and 32 °C were the most suitable for B. tabaci MED development and viability across all tested host plants, whereas 35 °C proved harmful for insects reared on legumes. We observed a temperature threshold (°C) and thermal constant (degree-days) that varied according to the host plant, ranging from 9.81 °C and 384.62 for soybean to 11.17 °C and 333.33 for bell pepper, respectively. The main endosymbionts were in a ratio of 80% Hamiltonella and 20% Cardinium. These results allow the future mapping of risk for the MED biotype on different host plants in Brazil and elsewhere in South America. Full article

Tomato chlorosis virus (ToCV) is a highly infectious plant virus that poses a significant threat to the Solanaceae family worldwide. Despite its widespread impact, effective control remains challenging due to its vector-borne transmission by whiteflies. To facilitate early detection and potential therapeutic intervention, this study aimed to identify diagnostic epitopes through a comprehensive bioinformatics approach combining comparative genomics and artificial intelligence-based structural modeling. We analyzed forty-four complete ToCV genomes to identify highly conserved regions and uncovered an orphan clade, indicating evolutionary divergence. Subcellular localization and transmembrane domain predictions revealed viral proteins with extracellularly exposed peptide regions. Structural modeling using AlphaFold3 further validated the stability and accessibility of these domains. By integrating these findings with epitope prediction algorithms, this study identified four highly promising epitope candidates, which are suitable for the development of antibody-based diagnostic kits and antiviral therapeutics targeting ToCV. These epitopes provide a strong foundation for the development of antibody-based diagnostic kits or antiviral therapeutics targeting ToCV. Full article

Cassava Mosaic Disease (CMD) is a major constraint to cassava production in Côte d’Ivoire, causing significant yield and income losses for smallholder farmers. Despite its high prevalence, farmers’ knowledge and understanding of the disease remain limited. To address this issue, the Central and West African Virus Epidemiology (WAVE) Regional Center of Excellence provided capacity building for farmers in the major cassava growing regions. This study assesses the impact of the WAVE’s trainings and awareness campaigns on farmers’ knowledge of the disease and the management methods they adopted. Mixed socio-agronomic data were collected from 290 farmers, and CMD epidemiological parameters were assessed in 82 farms. Data were analysed using propensity score matching (PSM), followed by a Tobit regression model to assess the determinants and intensity of adoption of CMD management practices, using Stata. The results showed that trained farmers had a better understanding of CMD compared to untrained farmers. On average, trained farmers adopted 2.36 disease management practices (DMPs) compared to 1.55 DMPs for untrained farmers. Participation in WAVE’s training sessions and a sound knowledge of CMD positively influenced both the adoption and intensity of adoption of DMPs. However, there was no significant difference in CMD incidence between beneficiary areas (54.55%) and non-beneficiary areas (54.95%), likely due to the unavailability of disease-free planting material, inadequate agricultural practices, and high populations of whiteflies (Bemisia tabaci). This study shows the importance of awareness campaigns in the sustainable management of crop diseases in general and CMD in particular and suggests the need to train farmers on disease management and provide them with healthy planting materials. Full article

This study investigated the abundance and richness of insect pests and beneficial insects on 20 squash cultivars across three seasons in middle Georgia, U.S. Insects were sampled using yellow sticky cards, pan traps and sweep nets. Bemisia tabaci Gennadius (sweet potato whitefly) was prevalent in all seasons, while other key pests showed distinct seasonal peaks. Diaphania hyalinata Linnaeus (melonworm) peaked mid-July in summer 2021 (21 June–1 August), while Thysanoptera species, Acalymma vittatum Fabricius (striped cucumber beetle), and Diabrotica balteata LeConte (banded cucumber beetle) peaked late July-early August. In fall 2021 (4 October–14 November), Epilachna borealis (squash beetle), D. hyalinata, and D. nitidalis Stoll (pickleworm) were more active in early to mid-October, whereas D. undecimpunctata howardi Barber (spotted cucumber beetle) peaked in late November. In fall 2022 (17 October–20 November), D. balteata and D. undecimpunctata howardi peaked mid October to early November, while Anasa tristis DeGeer (squash bug) peaked in mid–late November. Orius insidiosus Say (minute pirate bug) peaked in late summer 2021 and remained stable in fall 2021. Pollinators were most active in mid-fall. Cultivars influenced insect abundance. ‘Saffron’ and ‘Amberpic 8455’ harbored the most O. insidiosus and fewer D. balteata and Thysanoptera species. ‘Golden Goose Hybrid’ had the highest moth numbers. These patterns suggest that cultivar traits influenced pest susceptibility and beneficial arthropods’ activity. Temperature and relative humidity were positively correlated with A. vittatum and E. borealis numbers, but rainfall negatively affected bees. These findings underscore the importance of cultivar selection and weather condition considerations in integrated pest management. Full article