Search Results (625)

Pentastiridius leporinus (Hemiptera: Fulgoromorpha: Cixiidae) is considered the main vector of three phloem-restricted pathogens, γ-proteobacteria ‘Candidatus Arsenophonus phytopathogenicus’, ‘Candidatus Phytoplasma solani’ (Stolbur phytoplasma), and 16SrXII-P phytoplasma, which infect two economically important crops, sugar beet and potato. In this study, four pop-up tents (1 m²) were set up in a carrot (Daucus carota L.) field located in Bingen on the Rhine to determine whether egg laying, development of nymphs, and infection is possible on this vegetable. We further show that the planthopper P. leporinus can complete significant parts of its life cycle on carrots in the field, suggesting that it has expanded its host range to this crop in addition to sugar beet and potato. In addition, this study shows that P. leporinus is able to transmit phloem-restricted pathogens to carrots. Full article

Lygus pratensis is a major pest of cotton, causing serious damage to cotton production. This study designed species-specific PCR detection primers for L. pratensis, established a detection system to identify L. pratensis DNA in the intestinal contents of predatory natural enemies, and investigated the control potential of four species’ predatory natural enemies against L. pratensis. The results indicated that 826 predatory natural enemies were collected from cotton fields belonging to two classes, five orders, and twelve families. Among these, 9 species of insecta natural enemies accounted for 54.12% of the total number of predatory natural enemies collected, while 14 species of arachnida predatory natural enemies comprised 45.88%. Of the 806 natural enemies tested, 5.58% were found to be positive for L. pratensis, all of which were arachnid predators, specifically Ebrechtella tricuspidata, Xysticus ephippiatus, Hylyphantes graminicola, and Oxyopes sertatus. The predation response of these four spider species to the fourth to fifth instar nymphs and adults of L. pratensis adhered to the Holling II model. The theoretical predation (a′/Th), daily maximum predation rate (T/Th), and searching effect for the fourth to fifth instar nymphs and adults of L. pratensis of the four spider species were assessed. According to the results, the species can be ranked in terms of their predatory and searching efficiency as follows: O. sertatus > E. tricuspidata > X. ephippiatus > H. graminicola. Four species of spiders had the highest theoretical predation against L. pratensis nymphs, ranging from 23.71 to 60.86, and adults, ranging from 22.14 to 50.25. Therefore, these four spider species could be utilized for L. pratensis management. This study identified the main predatory natural enemies of L. pratensis and their pest control capabilities, providing a scientific basis for selecting and utilizing natural enemies in integrated pest management (IPM) strategies. This will help promote ecological and green pest control of L. pratensis in cotton-growing areas. Full article

Diaphorina citri is the primary global vector of “Candidatus Liberibacter asiaticus”, the bacterium responsible for Huanglongbing. Syntaxin-1A (Syx1A), a member of the Qa-SNARE family, is essential for vesicle fusion and signal transduction, though its function in hemipteran insects remains poorly understood. This study presents the first comprehensive analysis of Syx1A expression in D. citri. Transcripts were detected across all life stages, with peak expression in the salivary glands. RNAi silencing of Syx1A reduced mRNA levels by 39.0% in nymphs and 58.0% in adults, resulting in 58.3% nmortality in nymphs within 5 days and 73.3% in adults within seven days, along with significant weight loss. Treated females showed marked declines in fecundity, ovarian degeneration, and deficient yolk deposition. RT-qPCR confirmed significant downregulation of Vg1, VgA, and VgR. These findings establish Syx1A as a regulator of growth and reproduction in citrus psyllids via modulation of yolk synthesis. RNAi targeting of Syx1A represents a promising strategy for ecologically sound pest control and may contribute to efforts in halting the transmission of the Huanglongbing pathogen CLas. 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

Cyclaniliprole is a novel third-generation anthranilic diamide insecticide which has broad-spectrum efficacy against various pests, including aphids. Rhopalosiphum padi and Schizaphis graminum are the two primary aphid species that infest wheat crops. This investigation evaluates cyclaniliprole’s acute toxicity and sublethal and transgenerational effects on both aphid species. The acute toxicity assessment revealed obvious insecticidal activity, with 24 h LC₅₀ values of 38.56 mg/L for R. padi and 33.71 mg/L for S. graminum. Sublethal exposure (LC₁₅ and LC₃₅ in R. padi; LC₃₅ in S. graminum) significantly reduced adult longevity and fecundity in the F₀ generation. In the F₁ generation, cyclaniliprole at LC₃₅ significantly reduced the fourth nymph stage in R. padi, whereas at LC₁₅, it shortened the third nymph stage duration in S. graminum compared to the control. Sublethal concentrations (LC₁₅ and LC₃₅) of cyclaniliprole significantly reduced age-stage-specific survival rate (s_xj), age-specific survival rate (l_x), age-specific maternity (l_xm_x), and age-stage life expectancy (e_xj) in the F₁ generation of R. padi, while only LC₃₅ decreased l_x, l_xm_x, and e_xj in S. graminum. Additionally, LC₃₅ significantly reduced the net reproductive rate (R₀) in the F₁ generation of R. padi compared to the control. These findings suggest that cyclaniliprole exhibit notable acute toxicity against both aphid species and that sublethal concentrations adversely affected the F₀ generation, with no observed hormetic effects in the F₁ generations of R. padi and S. graminum. The findings offer valuable insights for assessing the comprehensive insecticidal potential of cyclaniliprole. Full article

Microbial symbioses play crucial roles in insect physiology, contributing to nutrition, detoxification, and metabolic adaptations. However, the microbial communities associated with the lac insect Llaveia axin axin, an economically significant species used in traditional lacquer production, remain poorly characterized. In this study, the bacterial diversity and community structure of L. axin axin were investigated using both culture-dependent and culture-independent (metagenomic) approaches, combined with fatty acid profile analysis. The insects were bred at the laboratory level, in controlled conditions, encompassing stages from eggs to adult females. Bacterial strains were isolated from bacteriomes and identified through 16S rRNA gene amplification and genomic fingerprinting through ARDRA analysis. Metagenomic DNA was sequenced using the Illumina MiSeq platform, and fatty acid profiles were determined by gas chromatography–mass spectrometry (GC-MS). A total of 20 bacterial strains were isolated, with Acinetobacter, Moraxella, Pseudomonas, and Staphylococcus detected in first-instar nymphs; Methylobacterium, Microbacterium, and Bacillus in pre-adult females; and Bacillus and Microbacterium in adults. Metagenomic analysis revealed key genera including Sodalis, Blattabacterium, and Candidatus Walczuchella, with Sodalis being predominant in early stages and Blattabacteriaceae in adults. Fatty acid analysis identified palmitic, oleic, linoleic, arachidic, and stearic acids, with stearic acid being the most abundant. These results suggest that dominant bacteria contribute to lipid biosynthesis and metabolic development in L. axin axin. Full article

This article presents a deep learning approach for classifying the developmental stages (larvae, nymphs, adult females, and adult males) of Ixodes ricinus ticks, the most common tick species in Europe and a major vector of tick-borne pathogens, including Borrelia burgdorferi, Anaplasma phagocytophilum, and tick-borne encephalitis virus (TBEV). Each developmental stage plays a different role in disease transmission, with nymphs considered the most epidemiologically relevant stage due to their small size and high prevalence. We developed a convolutional neural network (CNN) model trained on a dataset of microscopic tick images collected in the area of Upper Silesia, Poland. Grad-CAM, an XAI technique, was used to identify the regions of the image that most influenced the model’s decisions. This work is the first to utilize a CNN model for the identification of European tick fauna stages. Compared to existing solutions focused on North American tick species, our model addresses the specific challenge of distinguishing developmental stages within I. ricinus. This solution has the potential to be a valuable tool in entomology, healthcare, and tick-borne disease management. Full article

Antipredator behaviors in animals often vary with developmental stage, microhabitat, and social context, yet few studies examine how these factors interact in species that undergo ontogenetic shifts in chemical defense. The spotted lanternfly (Lycorma delicatula) is an invasive planthopper whose nymphs transition from cryptically colored early instars to aposematically colored fourth instars that feed primarily on chemically defended host plants. We conducted 1460 simulated predator attacks on nymphs across four developmental stages to examine how antipredator behavior varies with instar, plant location (leaf vs. stem), host plant species, and local conspecific density. Nymphs exhibited three primary responses: hiding, sidestepping, or jumping. We found that location on the plant had the strongest effect, with nymphs on stems more likely to hide than those on leaves. Older instars were significantly less likely to hide and more likely to sidestep, particularly on stems, suggesting reduced reliance on energetically costly escape behaviors as chemical defenses accumulate. First instars were less likely to jump from their preferred host plant (tree of heaven) compared to other plant species. Higher local conspecific density reduced hiding probability, likely due to the dilution effect. These results demonstrate that antipredator strategies in L. delicatula are flexibly deployed based on developmental stage, microhabitat structure, and social context, with implications for understanding evolution of antipredator behavior in chemically protected species. Full article

Garlic root maggots are the main pest of garlic in Qi County, Henan Province, China, which has become an important factor restricting the development of the garlic industry. Earwigs play an important role in controlling root maggots because of their similar ecological niches. In this study, through DNA barcoding and morphological identification, the following root maggots and main earwigs species from Qi County were quickly identified: Delia platura (Meigen), Bradysia odoriphaga Yang et Zhang, Delia antiqua (Meigen), Muscina angustifrons (Loew), Lucilia sericata (Meigan), and the main species of earwigs was Gonolabis marginalis (Dohrn). D. platura was the dominant species and accounted for 98% among all garlic root maggots. The predation ability for each stage of G. distincta on the larvae and pupae of D. platura showed that G. distincta at different developmental stages preyed on both the the larvae and the entire pupae of D. platura. Among them, female adults had the strongest predation ability and the largest daily predation on first instar larvae of gray D. platura (71.25 ± 0.66). First instar nymphs of G. distincta also had a certain predation ability with the daily predation of first instar larvae being (1.85 ± 0.13). The predation ability of G. distincta at different instars on the larvae of the same instar of D. platura increased with the increasing of the instar. For the first to second instar larvae of D. platura, the female adult of G. distincta had the strongest predation ability, followed by the male adult of G. distincta, and then the fifth instar nymph of G. distincta. There was no significant difference in the predation ability between the male and female adults of G. distincta, but the adults’ predation capacities were significantly higher than that of the fifth instar nymph of G. distincta. The capacity of the fifth instar nymph of G. distincta was significantly higher than the fourth instar nymph of G. distincta, the fourth instar nymph of G. distincta was significantly higher than the first to third instar nymphs, and there was no significant difference in the predation amount among the first to third instar nymphs. The predation selection experiment indicated that the fifth instar nymphs and the male and female adults of G. distincta showed a positive preference for the first to third instar larvae of D. platura and a negative preference for the pupae of D. platura. Our study provided a preliminary scientific basis for green prevention and control of garlic root maggot. Full article

The tarnished plant bug, Lygus lineolaris (TPB), (Palisot de Beauvois), and the western tarnished plant bug (WTPB), Lygus hesperus, Knight, are major agricultural pests that cause significant damage to a wide range of crops in the southeastern and southwestern United States. Flonicamid (commercial name: Carbine 50WG) is generally effective against various sap-feeding pests, including both L. hesperus and L. lineolaris. This study evaluated the toxicity of flonicamid on third-instar nymphs and adults of both Lygus species under laboratory conditions. Two bioassay methods were used: spray application to assess both contact and oral toxicity, and dipping to evaluate oral toxicity. Results showed that L. hesperus was significantly more susceptible to flonicamid than L. lineolaris across both bioassay methods. While no significant differences in toxicity were observed between spray and dipping assays, third-instar nymphs exhibited significantly higher sensitivity than adults in both species. The addition of piperonyl butoxide (PBO), a known inhibitor of cytochrome P450-monooxygenases (P450s), significantly enhanced the toxicity of flonicamid, suggesting that P450 enzyme plays a critical role in its detoxification. Sublethal exposure to flonicamid also induced increased P450 activity in both species. These findings provide valuable insights into the differences in susceptibility between L. lineolaris and L. hesperus to flonicamid and indicate that P450-mediated detoxification is critical for flonicamid metabolism. Such insights are valuable for early resistance monitoring and optimizing flonicamid application in integrated pest management programs. Full article

Nymphs of the ambar mutant of Orius laevigatus (Fieber) are orange-colored instead of the yellowish color of the wild-type individuals. Since there were no previous studies of the pigments of this species, we searched for differences in pigments of the pteridine family between both strains. Fluorescent compounds from nymph extracts were separated by cellulose thin-layer chromatography (TLC) and by size exclusion chromatography, followed by LC/MS/MS. The present study has allowed the identification for the first time in O. laevigatus of erythropterin, leucopterin, 7-methylxanthopterin, xanthopterin, isoxanthopterin, pterin, and biopterin. The quantification was performed by fluorometry after elution of the pteridines previously separated by TLC. The results showed that the orange color in the ambar nymphs was due to the accumulation of the orange pigment erythropterin. Additionally, mutant nymphs exhibited significantly elevated levels of pterin and reduced levels of leucopterin. The possibility that these differences were due to differences in xanthine dehydrogenase (XDH) activity was tested; the results indicated that XDH deficiency is unlikely to be responsible for the mutant phenotype. Considering that the ambar mutation is recessive, the mutant phenotype should, most likely, be due to a disruption in downstream metabolic steps involved in erythropterin processing. Full article

Due to the potential role of Auchenorrhyncha in the transmission of the bacterium Xylella fastidiosa in a wide variety of cultivations, during recent years in Europe, many studies have focused on species composition, abundance and seasonal appearance of Auchenorrhyncha. However, females and nymphs are difficult to identify, as species-level identification relies primarily on male genitalia morphology. Sampling was conducted over four years in olive fields in Lesvos Island, in the Northeast Aegean, Greece, using sweep nets and Malaise traps. Both adults and nymphs were collected, with males identified to species level, while females and nymphs were separated on different morphotypes. Representatives from each morphotype and identified adults were sequenced using the mitochondrial cytochrome oxidase subunit I (COI) gene. Using a classical morphological approach, 58 species were identified to species level, and using DNA barcoding, nymph morphotypes and females were successfully identified within the families Cicadellidae, Aphrophoridae, Delphacidae and Issidae. A phylogenetic tree was generated, clustering nymphs together with the corresponding adults. Our results demonstrate the utility of combining morphological and molecular methods for accurate species identification and highlight the importance of enriching online databases with additional species records. Full article

Aphis gossypii is a significant global pest that impacts numerous agricultural crops and vegetables, causing direct damage to food plants and indirect damage through the transmission of phytopathogenic viruses, primarily begomoviruses. In Panama, particularly in the Azuero region, viral infections transmitted by this aphid can affect a substantial share of tomato crops cultivated for industrial use. A traditional alternative to synthetic pesticides involves exploring plant extracts with insecticidal properties derived from wild plants found in our tropical forests, which can be easily prepared and applied by farmers. In this context, the present research aimed to evaluate the insecticidal activity of ethanolic extracts from the stems and leaves of Sphagneticola trilobata on both nymphs and adults of A. gossypii. Mortality was assessed at 24, 48, and 72 h after applying three doses of each extract (25, 50, and 100 µg/L). A standard phytochemical analysis to determine insecticidal activity revealed that both extracts exhibited significant efficacy at the highest concentration tested; however, the leaf extract demonstrated greater effectiveness at lower concentrations. A comprehensive metabolomic study indicated that the active compounds are diterpenes derived from the pimarenyl cation. These compounds have been extensively documented for their insecticidal potential against various insect species, suggesting that ethanolic extracts from this plant could serve as viable candidates for agricultural insecticides to combat aphid infestations. Full article

Mayfly nymphs are reliable indicators of aquatic habitat quality, and whilst their presence and relative abundance are often used in bioassessment schemes, it is important to recognise that these attributes are affected by the sampling method employed. To test these effects, we sampled stream habitats for mayflies using two commonly used techniques in a standardised setup: aquatic sweep nets and manual collection from stones. These methods resulted in different success rates in detecting certain taxa depending on their biological traits (preferred microhabitat and locomotion type). Whilst species lists generally overlapped between the two methods, they yielded different values of total abundance, taxon richness, Shannon–Wiener’s diversity index, assemblage saprobic index, and general community structure. These results suggest that reliance on a single collection method is prone to yield only partial information for ecological assessments and emphasises the importance of employing a sampling technique that is appropriate for the study question and goals or combining more than one method. Based on these findings, we outline the scientific justifications for using each sampling method. Full article

Watermeal (Wolffia globosa) is an emerging sustainable feed ingredient, valued for its rapid growth, high protein content, and rich nutrient profile, offering great potential to improve the efficiency and sustainability of edible cricket production systems through efficient resource use and reduced environmental impact. This study aimed to evaluate the effects of replacing commercial cricket feed with dried watermeal and to determine the optimal substitution level for the production performance of two-spotted crickets (Gryllus bimaculatus). Seven dietary treatments were tested, namely 0% (control; T1), 10% (T2), 25% (T3), 50% (T4), 75% (T5), 90% (T6), and 100% (T7). Crickets were reared for four weeks in an open system with 6 replicates per treatment, with each containing 120 nymphs. Body weight, feed intake, and survival rate were recorded weekly, and a production index was calculated at the end of the trial. Results showed average growth rates ranging from 7.40 to 28.20 mg/day, feed conversion ratios (FCR) between 1.03 and 1.68, survival rates of 29.28% to 69.73%, and production index values from 24.00 to 128.30. A significant decline in production efficiency (p < 0.05) was observed at substitution levels of 75% and above, with the 100% watermeal group showing the lowest production efficiency (p < 0.05), likely due to nutrient imbalances and indigestible compounds. Segmented regression analysis identified 36.7% as the optimal level of watermeal supplementation. In terms of body composition, crickets fed diets containing up to 50% watermeal (10%, 25%, and 50%) showed crude protein, crude fat, crude fiber, and ash contents comparable to those fed the commercial diet. This finding suggests that dried watermeal can replace up to 50% of the commercial cricket feed without negatively affecting growth performance, survival, or nutritional quality, with 36.7% identified as the optimal replacement level for maximizing production efficiency. Full article