Search Results (63)

LED-enhanced sticky traps improve monitoring of greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae), but their effects on its parasitoid, Encarsia formosa Gahan (Hymenoptera: Aphelinidae), are unclear, which may compromise biological control. Methods: We quantified E. formosa visual responses in climate-chamber multiple-choice arenas using six LED colors at equal photon flux (8.1 μmol m⁻² s⁻¹) and in greenhouse choice/no-choice assays comparing a standard yellow sticky trap with a green LED-enhanced yellow trap, with and without host-infested tomato leaves. We further tested modified LED traps (green LEDs with white or green backgrounds) and assessed intensity-dependent responses (18.0–25.6 μmol m⁻² s⁻¹). Results: E. formosa showed the highest attraction to green LEDs (peak ≈ 521–524 nm) and a significantly lower response to other colors. In greenhouse assays, E. formosa preferred the standard yellow sticky trap over the LED-enhanced yellow trap; in no-choice tests, only 9% were recaptured on the LED-enhanced yellow trap, both without and with hosts. Modified traps with white or green backgrounds substantially increased E. formosa recapture (≈54% higher than the yellow-background LED trap). Encarsia formosa attraction to the white-background LED trap declined with increasing intensity (61% at 18.0 to 4% at 25.6 μmol m⁻² s⁻¹), whereas whitefly captures were stable to slightly higher. Conclusions: The standard LED-enhanced yellow trap is compatible with E. formosa releases and does not disrupt biocontrol. Modified LED traps show promise for simultaneous monitoring of E. formosa and whiteflies, warranting validation under commercial conditions. Full article

Mowing is a widely used agricultural management practice, yet its role in shaping plant–insect interactions remains largely unexplored. In this study, we investigated how mowing influences resistance of licorice (Glycyrrhiza uralensis) to the whitefly Bemisia tabaci by integrating behavioral assays with volatile analysis, transcriptomics, and metabolomics. Feeding preference assays showed that adult whiteflies strongly preferred new plants over mowed plants. Developmental assays further revealed that whiteflies exhibited a prolonged egg stage and extended egg-to-adult developmental duration on mowed plants, while adult longevity was not significantly affected. Gas chromatography–mass spectrometry analysis identified 31 volatile compounds in licorice, with alcohols dominating the volatile profile of new plants and terpenoids dominating that of mowed plants. Whitefly infestation significantly increased ester compounds in both plant types. Differential volatile analysis highlighted cis-3-hexen-1-ol and trans-3-hexen-1-ol as dominant compounds in new plants, whereas 3-carene and β-pinene were predominant in mowed plants. Transcriptomic analysis revealed that mowing primarily affected genes associated with primary metabolism and ribosome-related pathways, whereas whitefly infestation induced extensive transcriptional reprogramming, including activation of flavonoid biosynthesis, flavone and flavonol biosynthesis, MAPK signaling, and plant circadian rhythm pathways. Metabolomic profiling identified substantial accumulation of flavonoids, flavonols, and isoflavonoids following whitefly feeding. Integrated multi-omics analysis identified flavonol biosynthesis as a core pathway underlying licorice defense against B. tabaci. Overall, this study demonstrates that mowing primes G. uralensis for enhanced resistance to whitefly infestation by reshaping volatile emissions, activating secondary metabolite biosynthesis, and inducing coordinated defense signaling networks. These findings provide new insights into plant–insect interactions and highlight mowing as a potential component of sustainable pest management strategies. Full article

A field trial was conducted at two locations in northern Ghana over two successive years to determine the optimal insecticide application timings for mitigating non-lepidopteran pest infestations in a cowpea (Vigna unguiculata (L.) Walp.) variety, Songotra-T. This variety was genetically engineered to resist damage by the Maruca pod borer (MPB) (Maruca vitrata Fab.; Lepidoptera: Crambidae). A split-plot design, with cowpea variety as the main plot factor (Songotra-T vs. Songotra) and insecticide spraying regimes as the sub-plot, was used. Spraying treatments ranged from no spray to three applications at key growth stages (50% flowering, pod initiation, and 50% podding). Data were collected on pest infestation, pod damage, and grain yield. An economic analysis of the spraying regimes tested was performed using yield data. Significant spraying regime effects were observed for non-lepidopteran pests such as whiteflies (p = 0.034), thrips (p = 0.006) and the pod-sucking bugs complex (p < 0.05). Variety effects were mainly significant for MPB infestation and damage to pods. Songotra-T consistently produced approximately 2-fold higher yields than Songotra. Among spraying regimes, two applications at pod initiation and 50% podding resulted in the highest yields, while additional sprays offered no significant advantage. This spraying regime also resulted in a higher return on investment. These findings demonstrate that the adoption of Songotra-T mitigates excessive insecticide use in cowpea production. Full article

Massive strandings of holopelagic Sargassum cause major ecological and economic problems, but its conversion into bioproducts offers a sustainable alternative. This study assessed the potential of holopelagic Sargassum (S. fluitans and S. natans) collected in the Caribbean as ecofriendly insecticides against the whitefly Bemisia tabaci, a major pest of tomato crops. Extracts were produced using green methods: ultrasound-assisted extraction (UAE) and ultrasound-assisted enzymatic hydrolysis (UAEH) with enzymes cocktails. Biochemical analyses revealed high mineral and polysaccharide contents, varying with the extraction technique. Extracts were tested at 1–6% (w/v) using clip-cage (adults) and leaf-dip (eggs) methods. All extracts reduced adult survival, with UAE and UAEH-P/C extracts achieving over 50% mortality at ≥4% concentration after 48 h (LD₅₀: 3.9–4.5%). Egg mortality was significant only with UAE and UAEH-P extracts at 6% (LD₅₀: 1.9–2.8%). These results suggest insecticidal activity through both ingestion and cuticle/embryo disruption. Although enzymatic extraction did not markedly enhance biochemical yields, extracts showed, for the first time, promising biocidal and ovicidal properties. This research highlights holopelagic Sargassum as a renewable source of natural insecticidal compounds, supporting sustainable management of both invasive algal biomass and agricultural pests. Full article

In this study, the invasive orange spiny whitefly (“OSW”; Aleurocanthus spiniferus) and a species of Encarsia parasitising its puparia were studied in three different areas of the province of Modena (Emilia-Romagna, northern Italy): a pear orchard in Bomporto, an organic pear orchard in Carpi, and the semi-natural botanical garden “La Pica” in San Felice sul Panaro. The material of both species was collected for taxonomic and molecular studies. The abundance of OSW and parasitoid activity were surveyed in whitefly puparia, with a focus on the botanical garden. A total of 1800 leaves of Malus domestica, Pyrus communis and Vitis vinifera were sampled to assess whitefly infestation. The results showed a significant variation in the abundance of A. spiniferus puparia, with the highest infestation observed in V. vinifera. Morphological and molecular analyses, including mitochondrial COI and rRNA 16S for whiteflies and COI and 28S for parasitoids, confirmed the identity of A. spiniferus and identified the parasitoid as Encarsia nipponica. Molecular data also revealed the presence of three haplotypes of A. spiniferus, including a haplotype from China, new to Europe. The parasitisation rate by E. nipponica was low (0.015%). Our results provide the first European record of E. nipponica and new genetic data on the invasion pathways of A. spiniferus. Collectively, these findings offer a critical baseline for monitoring their ecological interactions and developing future pest management strategies. Full article

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

Whiteflies of the Bemisia tabaci complex, along with the plant viruses they transmit, pose significant challenges to crop production worldwide. Upon infestation or infection, intimate interactions occur between plant hosts and these pests, influencing the spread and severity of pest-related epidemics in natural and agricultural ecosystems. This review explores the role of the salicylic acid (SA) signaling pathway, an essential component of plant defense, in modulating plant interactions with whiteflies and whitefly-borne viruses. We first outline the biosynthesis and signal transduction of SA. We then analyze how whitefly infestation activates the SA signaling pathway and how this defense response affects whitefly performance and preference. Next, we explore the interactions between the SA signaling pathway and whitefly-borne plant viruses, especially begomoviruses, which often activate and manipulate this pathway. We also examine how the SA signaling pathway influences plant–whitefly–virus tripartite interactions, highlighting the significant role of this defense pathway in whitefly-induced changes in plant–virus interactions and virus-induced changes in plant–whitefly interactions. Finally, we identify key areas for future research to further unravel the complexities of plant interactions with whiteflies and whitefly-borne viruses. Full article

Expanding genetic variability of cultivated cotton (Gossypium hirsutum) is essential for improving fiber quality and pest resistance. This study synthesized allotetraploids through interspecific hybridization between G. herbaceum (A₁) and G. nelsonii (G₃). Upon chromosome doubling using 0.2% colchicine, fertile F₁C allotetraploids (A₁A₁G₃G₃) were developed. Cytogenetic analysis confirmed chromosome stability of synthetic allotetraploids, and 74 polymorphic SSR markers verified hybridity and parental contributions. The F₁C hybrids exhibited enhanced resistance to cotton aphids (Aphis gossypii) and whiteflies (Aleyrodidae), with respective infestation rates of 5.2–5.6% and 5.4–5.8%, lower than those of G. hirsutum cv. Ravnak-1 (22.1% and 23.9%). Superior fiber length (25.0–26.0 mm) was observed in complex hybrids and backcross progeny, confirming the potential for trait introgression into elite cultivars. Phylogenetic analysis based on SSR data clearly differentiated G. herbaceum from Australian wild species, demonstrating successful bridging of divergent genomes. The F₁C hybrids consistently expressed dominant G. nelsonii-derived traits regardless of the hybridization direction and clustered phylogenetically closer to the wild parent. These synthetic allotetraploids could broaden the genetic base of G. hirsutum, addressing cultivation constraints through improved biotic stress resilience and fiber quality traits. The study establishes a robust framework for utilizing wild Gossypium species to overcome genetic bottlenecks in conventional cotton breeding programs. Full article

Bemisia tabaci is a major agricultural pest that affects both greenhouse and field crops by feeding on plant sap, which impairs plant growth, and by secreting honeydew, promotes sooty mold growth that further reduces photosynthesis. Additionally, these insects are vectors for viruses such as the cucurbit chlorotic yellows virus (CCYV), which causes significant damage to cucurbit crops. Traditional chemical pesticide treatments have limitations, including the development of resistance, harm to non-target organisms, and environmental contamination. Traditional chemical pesticides have limitations when it comes to controlling plants infested by CCYV and whitefly. However, the underlying reasons for these limitations remain unclear, as does the impact of entomopathogenic fungi on whitefly responses. This study explores the potential of using biological control agents, specifically Beauveria bassiana and Purpureocillium lilacinum, to manage whitefly populations and control CCYV transmission. Laboratory experiments were conducted to evaluate the pathogenicity of these fungi on non/viruliferous whitefly. The results indicated that both fungi effectively reduced whitefly populations, with B. bassiana showing particularly strong adverse effects. Whiteflies infected with CCYV exhibited a higher LC₅₀ to B. bassiana and P. lilacinum. Furthermore, bio-pesticides significantly altered the bacterial microbiome dynamics of the whitefly. Interestingly, CCYV increased the susceptibility of whiteflies to entomopathogenic fungus. The findings suggest that these biocontrol agents offer a sustainable alternative to chemical pesticides. Our study unraveled a new horizon for the multiple interaction theories among bio-pesticides–insects–symbionts–viruses. Full article

Understanding the resistance mechanisms of plants against pests contributes to the sustainable deployment of plant resistance in Integrated Pest Management (IPM) programmes. The Mi-1 gene in tomato is the only one described with the capacity to provide resistance to different types of harmful organisms such as plant parasitic nematodes and pest insects, including the whitefly Bemisia tabaci MED (Mediterranean species). In this work, gene expression in the interaction of B. tabaci with susceptible tomato plants lacking the Mi-1 gene (cv. Moneymaker, compatible interaction), and with resistant plants carrying the Mi-1 gene (cv. Motelle, incompatible interaction) was studied using the oligonucleotide microarray technique. Both interactions were studied 2 and 12 days post infestation (dpi) of plants with adult insects. At 2 dpi, 159 overexpressed and 189 repressed transcripts were detected in the incompatible interaction, while these figures were 32 and 47 in the compatible one. Transcriptional reprogramming was more intense at 12 dpi but, as at 2 dpi, the number of transcripts overexpressed and repressed was higher in the incompatible (595 and 437, respectively) than in the compatible (71 and 52, respectively) interaction. According to the Mapman classification, these transcripts corresponded mainly to genes in the protein and RNA categories, some of which are involved in the defence response (signalling, respiratory burst, regulation of transcription, PRs, HSPs, cell wall or hormone signalling). These results provide a wealth of information about possible genes related to the resistance provided by the Mi-1 gene to B. tabaci, and whose role deserves further investigation. Full article

In Uganda, the common bean (Phaseolus vulgaris) is often infested by a complex of insect pests, but bean flies, aphids, bean leaf beetles, and flower thrips are the most important. Whereas yield losses due to these pests have been established, there is limited information on their population dynamics at different stages of crop growth and their effect on yield and yield components. In order to describe the population dynamics of selected common bean pests at various phases of bean crop growth, and their impact on yield and yield components, a study was carried out in Uganda during the 2016 second rains and the 2017 first rains in three agro-ecological zones. Bean flies, bean aphids, bean leaf beetles, whitefly, striped bean weevil, leafhoppers, and caterpillars were the main insects observed. Pesticide spray schedules were imposed to generate different populations of insect pests whose effects on yield and its components were determined. The findings indicate that spray regimes significantly influenced the abundance of bean flies and leafhoppers, but not the other insect pests. Additionally, except for caterpillars, insect pests were significantly influenced by crop growth stages, but only leafhoppers exhibited a significant negative relationship with grain yield. Furthermore, yield and yield components varied significantly between spray regimes, and there was a significant positive relationship between grain yield and yield components. Our study is important for informing growers on the stage of crop growth at which management tactics such as use of insecticides can be applied for different insect pests. Full article

This study investigates the settling preferences and feeding behavior of the Bemisia tabaci whitefly on six cassava cultivars using electrical penetration graph techniques. Six distinct electrical penetration graph waveforms—non-probing, stylet pathway, phloem salivation, phloem ingestion, intracellular puncture, and xylem feeding—were identified and analyzed. Significant differences in the frequency and duration of these waveforms were observed among the cassava cultivars. The whiteflies spent the majority of their time in the non-probing phase, particularly on the Huaybong 80, Kasetsart 50, Rayong 9, and Rayong 72 cultivars. CMR-89 cultivar exhibited higher total probe durations in the phloem salivation and ingestion waveforms, suggesting a greater potential for transmission of the Sri Lankan cassava mosaic virus. The study also examined trichome density and size across the cassava cultivars, revealing that CMR-89 had the highest density and small trichomes, while Huaybong 80 had the lowest density. Trichome characteristics significantly impacted whitefly behavior: larger trichomes were negatively correlated with whitefly settling, whereas higher trichome density was positively correlated with longer settling durations. These findings indicate that trichome-based resistance mechanisms are crucial in whitefly deterrence. Overall, the results suggest that cultivars with lower trichome density and larger trichomes are more resistant to whitefly infestation and subsequent Sri Lankan cassava mosaic virus transmission. These insights are valuable for cassava breeding programs focused on enhancing pest resistance, highlighting the importance of trichome characteristics in developing more resilient cassava varieties. Full article

Cowpea mild mottle virus (CPMMV, genus Carlavirus, family Betaflexividae) is an economically important virus infecting soybeans in Brazil, where it was initially identified in 1983. CPMMV is transmitted by the whitefly, Bemisia tabaci, and occasionally by seeds. Over the last three decades, the most invasive B. tabaci Middle East–Asia Minor 1 (MEAM1), and lately the Mediterranean (MED) cryptic species, have replaced the indigenous species in Brazil, with MEAM1 being predominant. In this study, we investigated the transmission properties of CPMMV by MEAM1 and MED, and their distribution in major soybean-growing areas in São Paulo State. Our results from transmission assays with a single insect revealed that MED is a more efficient vector compared to MEAM1, transmitting the virus within a two-minute inoculation access period. B. tabaci MEAM1 is still the predominant whitefly species in São Paulo State, but MED was also identified in different places, mainly in mixed infestations with MEAM1. Some areas transitioned to a predominance of MED over the three years, while others, where MED had previously been detected, showed a reduction in the insects during the same period. Understanding the transmission dynamics of CPMMV and the distribution of its vectors is crucial for implementing effective management strategies to control the virus spread and protect soybean crops. Further research into the mechanisms driving the shifts in whitefly species dominance and CPMMV distribution will be essential for sustaining soybean production in Brazil. Full article

Plants can respond to insect infestation and virus infection by inducing plant defenses, generally mediated by phytohormones. Moreover, plant defenses alter host quality for insect vectors with consequences for the spread of viruses. In agricultural settings, other organisms commonly interact with plants, thereby inducing plant defenses that could affect plant–virus–vector interactions. For example, plant defenses induced by omnivorous insects can modulate insect behavior. This study focused on tomato yellow leaf curl virus (TYLCV), a plant virus of the family Geminiviridae and genus Begomovirus. It is transmitted in a persistent circulative manner by the whitefly Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae), posing a global threat to tomato production. Mirids (Hemiptera: Miridae) are effective biological control agents of B. tabaci, but there is a possibility that their omnivorous nature could also interfere with the process of virus transmission. To test this hypothesis, this study first addressed to what extent the mirid bug Dicyphus hesperus Knight induces plant defenses in tomato. Subsequently, the impact of this plant–omnivore interaction on the transmission of TYLCV was evaluated. Controlled cage experiments were performed in a greenhouse setting to evaluate the impact of mirids on virus transmission and vector acquisition by B. tabaci. While we observed a reduced number of whiteflies settling on plants exposed to D. hesperus, the plant defenses induced by the mirid bug did not affect TYLCV transmission and accumulation. Additionally, whiteflies were able to acquire comparable amounts of TYLCV on mirid-exposed plants and control plants. Overall, the induction of plant defenses by D. hesperus did not influence TYLCV transmission by whiteflies on tomato. Full article