Search Results (108)

Background: Contemporary agriculture heavily relies on synthetic chemicals to ensure high yields and food security; however, their overuse has led to health issues and the development of pesticide resistance in pests. Researchers are now exploring natural, eco-friendly alternatives for pest control. Methods: This study evaluated two ethanol-based formulations (1.25% and 2.50%, v/v) derived from the tangerine peel (Citrus reticulata L. var. Clementina) against conventional chemical treatments and an untreated control group in the cultivation of potatoes (Solanum tuberosum L. var. Capiro). A randomised block design was used, with three blocks per treatment containing 45 plants. The experiment was conducted during the wet season (February–April 2023). Results: According to visual inspections and yellow traps, following weekly application from days 30 to 105 post-planting to monitor pest (e.g., Frankliniella occidentalis, Aphididae) and beneficial insect (e.g., Coccinellidae, Apis mellifera) populations, the 2.50% formulation performed similarly to chemical treatments against pests, whilst being harmless to beneficial insects. Post-harvest analysis showed that the formulations achieved 73% of conventional yields, with comparable tuber damage and levels of Premnotrypes vorax larvae. Conclusions: Toxicological tests confirmed the eco-friendliness of the formulations, making them suitable for small-scale Andean ‘chakras’ in organic farming and honey production, without the use of chemicals. Full article

Blueberry is a high-value fruit crop in the United States, with Georgia and Florida serving as important early-season production regions. In these areas, several thrips species (Thysanoptera: Thripidae), including Frankliniella tritici (Fitch), Frankliniella bispinosa (Morgan), and Scirtothrips dorsalis (Hood), have emerged as economically significant pests. While F. tritici and F. bispinosa primarily damage floral tissues, S. dorsalis targets young foliage. Their rapid reproduction, high mobility, and broad host range contribute to rapid population buildup and complicate the management programs. Species identification is often difficult due to overlapping morphological features and requires the use of molecular diagnostic tools for accurate identification. Although action thresholds, such as 2–6 F. tritici per flower cluster, are used to guide management decisions, robust economic thresholds based on yield loss remain undeveloped. Integrated pest management (IPM) practices include regular monitoring, cultural control (e.g., pruning, reflective mulch), biological control using Orius insidiosus (Say) and predatory mites, and chemical control. Reduced-risk insecticides like spinetoram and spinosad offer effective suppression while minimizing harm to pollinators and beneficial insects. However, the brief flowering period limits the establishment of biological control agents. Developing species-specific economic thresholds and phenology-based IPM strategies is critical for effective and sustainable thrips management in blueberry cropping systems. Full article

Thrips can be attracted or repelled by volatiles from different host plant species. Houttuynia cordata is a common plant species with a strong, offensive smell, and few pests have been detected on this plant. Here, the olfactory responses of Frankliniella occidentalis to H. cordata volatiles were tested using electroantennography (EAG) and behavioral bioassays in different types of olfactometers, and the behavioral responses of Orius similis, a natural enemy of F. occidentalis, to the related main volatile compounds were also evaluated. Y-tube olfactometer bioassays showed that F. occidentalis performed negative responses to H. cordata volatiles. Decanal (47.21%), 1-decanol (11.02%), dodecanal (7.13%), β-myrcene (5.12%), and decanoyl acetaldehyde (3.76%) were the more abundant components in the H. cordata volatile profile in gas chromatography–mass spectrometry analysis. EAG recordings showed that the antennae of female thrips could perceive these five compounds at a wide range of concentrations. In six-arm olfactometer bioassays, F. occidentalis exhibited negative responses to decanal, dodecanal, and decanoyl acetaldehyde at various doses but performed positive responses to 1-decanol and β-myrcene at certain doses. Furthermore, decanal, dodecanal, and decanoyl acetaldehyde at all concentrations showed no significant influences on the behavioral responses of O. similis. According to the results above, H. cordata can be a repellent plant species to F. occidentalis, and decanal, dodecanal, and decanoyl acetaldehyde show great potential for development as repellents for the control of F. occidentalis. In short, our results suggest that an integrated pest management system combining H. cordata-derived biopesticides with releases of the predator O. similis could effectively control F. occidentalis. Full article

The invasive pest Frankliniella occidentalis (western flower thrip, WFT) severely impacts agricultural production. RNA interference (RNAi) has emerged as a viable alternative to chemical control methods. Trehalose-6-phosphate synthase (TPS) is an important enzyme for the synthesis of trehalose in insects. The TPS gene is a potential target for RNAi-based pest control; however, its efficacy against WFTs remains unclear. Feeding with the synthesized dsFoTPS to WFT significantly increased the mortalities of first- and second-instar nymphs and adults and significantly decreased the number of eggs laid by adults within 72 h; the expression of FoTPS was significantly down-regulated in 24, 48, and 72 h. Ingestion of WFTs on Escherichia coli expressing dsFoTPS led to a marked increase in the total pre-reproductive period; reductions in survival rate, adult longevity, oviposition days, fecundity, peak reproduction value, the intrinsic rate of increase, the finite rate of increase, and the net reproductive rate; and an extension of the mean generation time. TPS gene expression was significantly down-regulated on days 7 and 28. A population simulation of WFTs fed with E. coli expressing dsFoTPS indicated that the population suppression was reduced to 1/34 of the control in 100 d. Oral delivery of E. coli expressing dsFoTPS effectively inhibited the survival, fecundity, and population growth of WFTs, offering a novel approach and rationale for the prevention and control of WFTs. Full article

Tomato spotted wilt virus (TSWV) is a highly destructive plant pathogen and transmitted by several thrips including the western flower thrips, Frankliniella occidentalis. A structural N protein encoded in the viral genome represents the nucleocapsid protein by binding to the viral RNA genome. However, it remains unknown how the RNA-binding protein specifically interacts with the viral RNA from host RNAs in the target cells. To study the molecular basis of N function, we produced the protein in Escherichia coli and the resulting purified recombinant protein was used to investigate the protein–RNA interactions. The recombinant N protein migrated on agarose gel to the anode in the electric field due to its high basic isoelectric point. This electrostatic property led N protein to bind to DNA as well as RNA. It also bound to both single-stranded (ssRNA) and double-stranded RNA (dsRNA). However, when the total RNA was extracted from plant tissues collected from TSWV-infected host, the RNA extract using the recombinant N protein was much richer in the TSWV genome compared to that without the protein. To investigate the specificity of N protein to ssRNA, the three-dimensional structure was predicted using the AlphaFold program and showed its trimeric oligomerization with the binding pocket for ssRNA. This was supported by the differential susceptibility of N protein with ssRNA and dsRNA against RNase attack. Furthermore, a thermal shift assay to analyze the RNA and protein interaction showed that ssRNA strongly interacted with N protein compared to dsRNA. In addition, the N gene was expressed along with the multiplication of the viral RNA genome segments from the segment-specific fluorescence in situ hybridization analysis in different tissues during different developmental stages of the virus-infected F. occidentalis. These results suggest that the functional trimeric N proteins bind to the viral RNA to form a basic nucleocapsid structure at a specific virus-replicating compartment within the host cells. Full article

The wide distribution of Frankliniella occidentalis is largely due to its extreme temperature adaptability. In current studies, most scholars consider environmental changes to be the main factor affecting insect temperature adaptation. However, our previous studies have shown that the adaptability of F. occidentalis to extreme temperature conditions can be strengthened through domestication. In this study, the population of F. occidentalis raised in the laboratory for a long time (2008–2022) under relatively constant temperature and humidity conditions was used as the experimental material. Over 14 years, changes in temperature tolerance after the same high- and low-temperature stress were evaluated by comparing the survival data of the 2010 population, 2016 population (more than 100 generations), and 2022 population (more than 200 generations). The survival data and LT₅₀ values demonstrated significant stage- and sex-specific differences in thermal tolerance: The cold tolerance of F. occidentalis improved significantly, with LT₅₀ decreasing from −12.5 °C (P2010) to −13.4 °C (P2022) for females and −11.5 °C to −13.0 °C for males. Notably, male adults showed higher survival rates than females at −14 °C and −15 °C. Meanwhile, heat tolerance increased most markedly in 2nd instar larvae (ΔLT50 = +4.1 °C). These findings indicate an environment-independent evolutionary pathway within the population, providing a new research direction for insect population evolution. Full article

Frankliniella intonsa (Thysanoptera: Thripidae) is a polyphagous pest that causes significant economic agricultural losses by damaging flowers, vegetables, and fruit trees. We performed an age-stage two-sex life table analysis to evaluate the performance and adaptability of F. intonsa against nine common vegetable crops cultivated in Guangxi: cowpea (Vigna unguiculata) (Fabales: Leguminosae), green beans (Phaseolus vulgaris) (Fabales: Leguminosae), soybean (Glycine max) (Fabales: Leguminosae), catjang cowpea (Vigna cylindrica) (Fabales: Leguminosae), courgette (Cucurbita pepo) (Cucurbitales: Cucurbitaceae), wax gourd (Benincasa hispida) (Cucurbitales: Cucurbitaceae), bitter gourd (Momordica charantia) (Cucurbitales: Cucurbitaceae), cucumber (Cucumis sativus) (Cucurbitales: Cucurbitaceae), and chieh-qua (Benincasa hispida) (Cucurbitales: Cucurbitaceae). Among the tested host crops, green beans, cowpea, and courgette significantly accelerated the growth rate and favored the reproductive success of F. intonsa. Green beans, cowpea, and courgette facilitated rapid growth and reproductive success. The mean generation times (T) and net reproductive rates (R₀) were as follows: 14.90 d, 17.09 d, 21.03 d, and 104.04, 45.51, 32.61. Bitter gourd and chieh-qua significantly suppressed population growth (T: 49.49 d, 0 d; R₀: 0.73, 0). Wax gourd, catjang cowpea, cucumber, and soybean exhibited moderate effects characterized by delayed development and lower reproductive output (T: 22.30 d, 20.30 d, 19.51 d, 32.73 d; R₀: 7.17, 25.22, 13.74, and 12.54). These findings highlight the critical role of crop type in F. intonsa population dynamics. Therefore, the agricultural production of green beans, cowpea, and courgette crops necessitates improved control measures and monitoring. Similar measures are needed for cucumber, catjang cowpea, soybeans, and wax gourds because they pose risks as potential hosts. Full article

The western flower thrips, Frankliniella occidentalis, a worldwide insect pest with its polyphagous feeding behavior and capacity to transmit viruses, follows a diurnal rhythmicity driven by expression of the circadian clock genes. However, it remained unclear how the clock signal triggers the thrips behaviors. This study posed a hypothesis that the clock signal modulates cGMP-dependent protein kinase (PKG) activity to mediate the diurnal behaviors. A PKG gene is encoded in F. occidentalis and exhibits high sequence homologies with those of honeybee and fruit fly. Interestingly, its expression followed a diel pattern with high expression during photophase in larvae and adults of F. occidentalis. It is noteworthy that PKG expression was clearly observed in the midgut during photophase but not in scotophase from our fluorescence in situ hybridization analysis. A prediction of protein–protein interaction suggested its functional association with clock genes. To test this functional link, RNA interference (RNAi) of the PKG gene expression was performed by feeding a gene-specific double-stranded RNA, which led to significant alteration of the two clock genes (Clock and Period) in their expression levels. The RNAi treatment caused adverse effects on early-life development and adult fecundity. To further analyze the role of PKG in affecting diurnal behavior, the adult females were continuously observed for a 24 h period with an automatic digitization device to obtain movement parameters and durations (%) in different micro-areas in the observation arena. Diel difference was observed with speed in RNAi-control females at 0.16 mm/s and 0.08 mm/s, in photo- and scotophase, respectively, whereas diel difference was not observed for the PKG-specific RNAi-treated females, which showed 0.07 mm/s and 0.06 mm/s, respectively. The diel difference was also observed in durations (%) in the control females, more strongly in the intermediate area in the observation arena. Speed and durations in the different micro-areas in mid-scotophase were significantly different from most photophase in the control females, while speed was significantly different mainly during late photophase when comparing effects of control and RNAi treatments in each light phase. Three sequential stages consisting of high activity followed by feeding and visiting of micro-areas were observed for the control females. For RNAi-treated females, the three phases were disturbed with irregular speed and visits to micro-areas. These results suggest that PKG is associated with implementing the diurnal behavior of F. occidentalis by interacting with expressions of the circadian clock genes. Full article

Western flower thrips (WFT), Frankliniella occidentalis (Pergande) [Thysanoptera: Thripidae], is a destructive pest of greenhouse ornamentals. Flowering yellow marigolds, Tagetes patula (L.) [Asterales: Asteraceae], have been shown to be attractive to WFT, implicating their suitability as a trap plant. However, functionality may vary in part due to crop variety, the growth stage of the crop in which the marigold trap plant is deployed and whether or not the crop plants have flowers present. The attractiveness of yellow marigolds was tested within several varieties of mature, flowering ornamental bedding plants that were flowering or had their flowers removed: Calibrachoa spp. Petunia spp. Verbena spp., Osteospermum spp., Impatiens haekeri and other marigolds. Trials were conducted in cages under controlled greenhouse conditions for six weeks. The effectiveness of orange vs. yellow marigolds as a trap plant was also assessed. The results showed that WFT were attracted to flowering marigolds and, over time, were present in greater numbers on these than crop plants for all crop species and varieties tested at varying levels of significance. Yellow marigold trap plants were the least effective when deployed within other marigold varieties. In crops with flowers, it took up to five weeks for the number of WFT on trap plants to surpass numbers on crop plants. In contrast, in crop varieties with their flowers removed, trap plants attracted WFT earlier, within one to two weeks, and harbored them in greater numbers over time. Orange, flowering marigolds were a less effective trap plant compared to yellow marigolds. These results confirm that flowering yellow marigolds are attractive to WFT and have potential as a trap plant in greenhouse ornamentals, particularly when crop plants do not have flowers. Full article

The efficacy of entomopathogenic nematodes (EPNs), Steinernema feltiae and Heterorhabditis bacteriophora, for controlling Frankliniella occidentalis (Thysanoptera: Thripidae, Pergande, 1895) in nectarine orchards, was evaluated, alongside their potential impact on honeybees (Apis mellifera, Hymenoptera: Apidae, Linnaeus, 1785). Field trials revealed that S. feltiae significantly reduced thrips populations and fruit damage compared to the control, while H. bacteriophora showed no significant effect. The reduction in feeding scars on fruits from S. feltiae–treated trees underscores its potential as a sustainable biocontrol agent. However, laboratory bioassays indicated that another EPN, Steinernema carpocapsae, induced delayed mortality in honeybees under high-exposure conditions, pinpointing the need for careful application to minimize risks to pollinators. These findings demonstrate the potential of S. feltiae for integrated pest management (IPM) in nectarine cultivation while emphasizing the importance of species-specific selection and pollinator safety. Future research should focus on optimizing application methods, understanding environmental influences on EPN efficacy, and assessing long-term impacts on pollinator health to ensure sustainable pest management practices. Full article

The Western Flower Thrips (Frankliniella occidentalis) constitutes a significant threat to rose greenhouses in Colombia. An eco-friendly approach to managing this pest involves using the predatory bug Orius insidiosus. The pest and its predator’s food search and selection mechanisms are influenced by ecological interactions mediated by volatile organic compounds (VOCs) emitted during plant–pest interactions. To investigate the role of VOCs in the foraging and host-selection behaviors of O. insidiosus, we conducted functional response assays in greenhouses and olfactometry experiments in laboratory settings. These experiments used flowers from two rose cultivars, with and without female adult thrips, over 24, 48, and 72 h. Functional response analysis revealed a shift in O. insidiosus foraging behavior based on the duration of thrips interaction with rose flowers, transitioning from a Type II to a Type III functional response between 24 and 48 h in the ‘Freedom’ cultivar. The maximum consumption rates increased significantly, from 7.98 individuals at 24 h to 16.18 individuals at 48 h, before slightly decreasing to 14.37 individuals at 72 h. This shift coincided with an increase in O. insidiosus preference for thrips-infested ‘Freedom’ flowers over time, with selection proportions rising from 0.37 at 24 h to 0.46 at 72 h, suggesting a learning effect on prey-searching behavior mediated by VOCs. Olfactometry analyses revealed that O. insidiosus did not respond to the same VOCs that attracted F. occidentalis during flower infestation. However, O. insidiosus responded to certain VOCs likely associated with floral resources such as nectar and pollen, which also attract pollinators and zoophytophagous predators. This observation suggests a potential overlap in the chemical cues used by O. insidiosus for distinct ecological purposes. These findings highlight the complex chemical ecology underlying predator–prey interactions in agroecosystems and underscore the importance of considering VOCs in shaping the foraging behavior of natural enemies and their interactions with insect pests. Full article

Western flower thrips (WFTs) are significant pests affecting various crops globally. Developing sustainable strategies for managing WFTs is essential for improving thrips management. Ethological control methods, particularly those employing volatile organic compounds (VOCs) emitted by plants to influence insect behavior, have emerged as a promising avenue for pest management. Natural hosts such as Alstroemeria provide an intriguing yet underexplored opportunity for developing attractants tailored to WFT management. This study examined the behavioral preferences of WFTs towards flowers of four commercial Alstroemeria cultivars, focusing on variations in VOC profiles. Using headspace solid-phase microextraction (HS-SPME), VOCs were captured in vivo from cultivars with contrasting levels of WFT infestation. Gas chromatography coupled with mass spectrometry (GC-MS) was employed to analyze the VOCs, with linear retention indices aiding compound identification. An untargeted volatile profiling-based comparative analysis revealed key VOCs that differed among cultivars, shedding light on their potential correlation with WFT behavior. Behavioral assays identified three specific VOCs—butyl butyrate, 1-methylnaphthalene, and citronellyl acetate—as influential in attracting WFTs. Attraction responses were concentration-dependent, with two tested concentrations eliciting significant behavioral effects. These findings highlight the potential of these active VOCs as components of novel attractants for WFT management. The results direct future research and the development of tools to integrate ethological strategies into sustainable pest management practices for crops. Full article

As two major pests of cowpea in South China, bean flower thrips [Megalurothrips usitatus (Bagnall)] and flower thrips [Frankliniella intonsa (Trybom)] always occur on the same plant. In this study, the two-sex life table parameters of these two species were investigated on three bean pods: cowpea (Vigna unguiculata L. var. Chunqiu Wujiadou), snap bean (Phaseolus vulgaris L. var. Yonglong 3), and green bean (Phaseolus vulgaris L. var. Linghangzhe) using standard cut bean protocols. Longevity of female adult M. usitatus showed no significant difference on cowpea and snap bean, but was shortest on green bean, with the highest fecundity on snap bean, followed by cowpea and green bean. Longevity and fecundity of female adult F. intonsa were both highest on cowpea, followed by snap bean and green bean. On snap bean, the population parameters (R₀, GRR, T) of M. usitatus were higher than F. intonsa, whereas r and λ were not different, suggesting that M. usitatus were more competitive on snap bean. On cowpea, the population parameters (R₀, GRR, r, λ) of F. intonsa were higher than M. usitatus, suggesting a competitive advantage of F. intonsa on cowpea. To better mimic field conditions, we investigated the survival and fecundity of adult M. usitatus under two distinct scenarios: when they could feed directly on cut surfaces of cowpeas (standard lab protocol), and when they could not. Adult survival of M. usitatus is not significantly influenced by whether or not they fed directly on cut surfaces of cowpeas. However, a notable decrease in fecundity was observed in M. usitatus that fed on surface-covered cut pods. This suggested that direct feeding on cut surfaces of cowpea did have an impact on thrips’ fecundity, offering fresh perspectives for future research into the growth and development of thrips in a laboratory. Our study suggests that experiments involving cut surfaces may be misleading, and further investigations are ongoing to address these concerns. Full article

Western flower thrips, Frankliniella occidentalis, is a serious worldwide pest of agriculture and horticulture, and its contact pheromone is 7-methyltricosane. Two enantiomers of 7-methyltricosane were synthesized for the first time. The centra of our strategy were chiral auxiliaries to introduce stereocenter, and Wittig coupling to connect two blocks. The overall yields of our synthesis were 29–30% with seven steps. The electroantennogram (EAG) and the contact behavioral responses revealed that (R)-, (S)- and racemic 7-methyltricosane were separately bioactive, and the racemate was the most bioactive in the male arrestant activity and the female EAG test. This result provides valuable insights, showing that the racemate could be used for the support of the control of western flower thrips, which could be more easily prepared relative to more expensive enantiopure pheromone. Full article

Frankliniella intonsa (Trybom) (Thysanoptera: Thripidae) is an important type of thrip and a polyphagous pest, which poses a serious threat to many crops, especially those in tropical regions of China. Its feeding behavior and the damage caused vary among different host plant species and are affected by ambient temperature and plant nutrients as well. The digestion rate is an important index for directly observing the digestion process, but there have been no studies directly measuring the digestion in thrips under the influence of different temperatures and host plants. Here, the digestion rate of F. intonsa was assessed by using a molecular diagnostic tool. We also determined the nutrient content in three host plant (mango, cowpea, and pepper), including soluble proteins, free fatty acids, soluble sugars, and water. The results showed that the high and low temperatures (16 °C and 32 °C) both seemed to accelerate the digestion of F. intonsa compared to the optimal temperature (26 °C) and the protein content of plants played an important role in the digestive response of F. intonsa to temperature changes. The findings can help reveal the feeding damage caused by F. intonsa to different plants and help to better understand its feeding ecology, according to its interaction with the host plant. Full article