The global occurrence of Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) intensifies reliance on synthetic insecticides, causing resistance and ecological risks. This study investigates rosemary (Rosmarinus officinalis L.) essential oil (REO) as a sustainable alternative, examining its effects on S. exigua behaviors and chemosensory mechanisms. Gas chromatography–mass spectrometry identified 3 dominant terpenoids (α-pinene, cineole, and verbenone) and 13 minor constituents (>1%) in the essential oil. Larval bioassays showed that REO significantly inhibited larval growth and development (P < 0.001), with persistent sublethal effects on subsequent stages. It also demonstrated concentration-dependent inhibition of larval feeding. At a concentration of 2%, the selective and nonselective feeding deterrence rate reached 62.01 and 78.40% (P < 0.001), respectively. Behavioral experiments further revealed that the essential oil had a concentration-dependent dual behavioral regulatory effect in that, at a concentration of 0.005%, it attracted oviposition and olfactory orientation, whereas at concentrations ≥0.05%, it showed significant repellency. In oviposition choice tests, 2% REO achieved a 49.92% (P = 0.008) repellency rate; in Y-tube olfactometer assays, the repellency rate was 75% (P = 0.028). Molecular docking revealed β-caryophyllene and verbenone form stable hydrophobic interactions with S. exigua odorant-binding protein OBP1 and OBP7, suggesting a critical role in disrupting olfactory recognition. These results indicate REO acts as a multitarget behavioral modulator, interfering with olfaction, development, feeding, and oviposition in S. exigua, thereby providing an ecofriendly pest management option.
Age-specific reproductive performance is an important component of the life history of organisms and is likely expected to maximize lifetime reproductive success. Parasitoid wasps are important insects for well-known biological control; successful reproduction of wasps is indispensable for mass rearing indoors and controlling pests in the wild. Here, we tested agespecific reproductive performance in the important egg parasitoid Anastatus disparis Ruschka (Hymenoptera: Eupelmidae) as potential biological control agents of many forest pests including Lymantria dispar L. Our results showed that reproductive performance mainly involving in eclosion ratio in A. disparis significantly increased with female age. Increased reproductive performance with age can be also explained by egg size significantly increasing as females aged. In addition, age and breeding experience are generally very closely linked with improving reproductive performance. However, our results suggested that breeding experience was unlikely to explain female A. disparis patterns of age-specific reproduction performance. Besides, our results provided potential guidance for massively rearing A. disparis indoors and its application in controlling pests in the wild.
Antonospora locustae (formerly Nosema locustae, Paranosema locustae) (Protozoa: Microsporida), an obligate protozoan parasite of orthopteran insects, has emerged as a model organism for microsporidian studies and is widely used in the commercial production of biocontrol agents for locust management. However, current methodologies for A. locustae isolation are constrained by exorbitant cost and limited accessibility of appropriate biochemical reagents. In this study, we evaluated an alternative method for A. locustae separation using sucrose density gradient centrifugation, achieving a reduced extraction cost of US $13.92 per test compared with traditional methods. The presence of A. locustae in separated fractions was verified through chromotrope 2R staining. Bioassays demonstrated that locusts inoculated with the isolated A. locustae exhibited significant mortality rates and polymorphic lethal phenotypes. These findings not only establish a cost-effective and efficient isolation methodology for A. locustae but also provide novel perspectives on its laboratory investigation and potential applications in locust control.
Of the mesofauna of the avocado (Persea americana) crop rhizosphere, most predatory mites belong to the order Mesostigmata, although only a few families have been considered for use in biological control programs targeting soil pests. Despite their potential value for agroecological management, this group has been poorly studied. Mites of the Astigmatina cohort (Acari: Sarcoptiformes) are widely used as prey in the mass rearing of various predatory mites that inhabit soil or plants, but their predation capacity has not been thoroughly evaluated. This research aimed to investigate the feeding habits and evaluate the biological control potential of a species from the Parasitidae family, native to an avocado-growing region in Michoac & aacute;n, Mexico. This article reports on the genus Psilogamasus (Parasitidae), a natural soil inhabitant in avocado crops, and investigates its potential as a predator across all developmental stages. Larvae, protonymphs, deutonymphs, males, and females of Psilogamasus were exposed to prey mites from the Astigmatina cohort through in vitro bioassays. The results showed that immature stages were highly voracious; however, larval and nymphal mortality suggested a need for supplementary food to complete development. Furthermore, females were observed to be the most active in searching for prey, consuming at least 50 more nymphs than males.
Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) is a major pest of stored grain environments, leading to contamination and economic damage globally. The extensive use of synthetic insecticides to control this pest raises concerns about resistance, toxicity, and environmental impacts. This study investigated the chemical composition and insecticidal potential of essential oil derived from Houttuynia cordata Thunberg leaves as a sustainable alternative. The essential oil was extracted via water distillation and analyzed using gas chromatography-mass spectrometry (GC-MS), identifying 9 major compounds. Alpha-myrcene (76.58%), alpha-ocimene (8.96%), and alpha-pinene (3.59%) were the most abundant. Bioassays were conducted to assess the contact toxicity, fumigation toxicity, and repellent activity of the essential oil against adult T. castaneum. The contact toxicity bioassay revealed increasing mortality over time, with a median lethal dose (LD50) of 30.14 & micro;L/mg adult and an LD90 of 49.78 & micro;L/mg adult at 72 h. The fumigation toxicity bioassay indicated a lethal median concentration (LC50) of 16.06 & micro;L/L air and LC90 of 41.86 & micro;L/L air at 72 h. Repellent activity bioassays demonstrated 100% at a concentration of 3.75 & micro;L/mL after 8 h. These findings suggest that H. cordata essential oil could serve as a promising botanical insecticide for managing T. castaneum. Its strong repellent activity, along with high contact and fumigant toxicity, supports its integration into sustainable pest management strategies as a natural alternative to synthetic pesticides.
Sphingidae (Latreille) is one of the largest families of tropical moths, with important roles in herbivory and pollination and great species richness. Although Veracruz has the largest number of hawkmoths recorded in Mexico, there are few studies and no research reported from the low deciduous forest or on mature stages in agricultural areas. This study aimed to evaluate the species richness of Sphingidae in an agricultural ecosystem associated with tropical deciduous forest fragments in Veracruz, Mexico. The study period for this work covers January 2023 to December 2024. Insects were collected using nocturnal capture methods with light traps from 18:00 to 06:00 h once each month. The results are equivalent to 288 effective hours of sampling, allowing the collection of 342 hawkmoths, representing 47 species from 22 genera, three subfamilies, and four tribes, with a 97.09% sample coverage. We report four new records for the state of Veracruz. Models indicated that temperature and precipitation explain 45.58% and 49.97% of the variability in abundance and species richness, respectively. This work includes the first records of hawkmoths associated with agricultural ecosystems and low deciduous forest in Veracruz and their relationship with environmental variables.
Mosquito-borne diseases remain a global health threat, necessitating the development of ecofriendly alternatives to chemical insecticides. This study evaluated the larvicidal activity of Cyperus rotundus L. extracts and the isolated compound Charantagenin D against Aedes (n-hexane, chloroform, methanolic ethyl acetate, and aqueous) were tested at concentrations ranging from 10 to 40 ppm. The n-hexane extract exhibited the highest efficacy, causing 100% mortality in fourth instar larvae of all three mosquito species at 40 ppm. Statistical analysis revealed significant differences among extracts and mosquito species (P < 0.001), with Ae. aegypti showing the highest susceptibility. Bioassay-guided fractionation of the n-hexane extract yielded nine fractions, of which Fraction 8 showed strong larvicidal activity. Spectroscopic analysis identified Charantagenin D, a triterpene glycoside, as the active constituent. Charantagenin D achieved 100% mortality at 40 ppm and exhibited a median lethal concentration of 16.179 ppm and a 90% lethal concentration of 31.065 ppm for Cx. quinquefasciatus, with comparable effects on the other two species. These findings highlight the potential of Charantagenin D as a botanical larvicide and support the use of plant-derived compounds in sustainable mosquito control strategies.
Spodoptera exigua (H & uuml;bner) (Lepidoptera: Noctuidae) is a major pest that impacts numerous agricultural crops worldwide. However, the management of S. exigua is complicated by its ability to develop resistance to various insecticides. Previous study has demonstrated that the combination of Cry1Ca protein and phoxim (Cry1Ca & thorn; phoxim) improves the effectiveness of controlling S. exigua. Nevertheless, the effects of Cry1Ca & thorn; phoxim on the bacterial communities within S. exigua larvae remain unclear. High-throughput sequencing technology was used in this research to compare the effects of Cry1Ca, phoxim, and Cry1Ca & thorn; phoxim on the symbiotic bacteria in S. exigua. The results indicated that larvae treated with Cry1Ca & thorn; phoxim exhibited a decrease in bacterial community evenness, resulting in a significant drop in the relative abundance of Firmicutes and a rise in Actinobacteria within the gut microbiota of S. exigua larvae. Moreover, there was a significant increase in the abundance of Rhodococcus in the treatment with Cry1Ca & thorn; phoxim. The results indicate that Rhodococcus could influence the toxicity of Cry1Ca and phoxim on S. exigua, providing novel insights and strategies for pest management.
Yellow traps are used to monitor Bactericera cockerelli & Scaron;ulc (Hemiptera: Triozidae), but their effectiveness depends on design and placement. Furthermore, information on their use for outdoor-grown peppers (Capsicum annuum L.), is limited. This study was performed in two experiments. In the first, assays were conducted using trap designs with one shape (e.g., circle, diamond, square, ellipse, triangle, and rectangle), two frames (e.g., yellow, black, blue, white, dark green, purple, and red) (e.g., yellow, dark green, clear green and lime green), and two color (e.g., dark green and black) patterns (e.g., small rectangles, large rectangles, horizontal stripes, large rectangle, large vertical stripe, and vertical stripes). Triangular, rectangular, and ellipsoid traps trapped the greatest number of B. cockerelli. Yellow, black, and dark green framed traps had the highest catches. No significant difference was detected among traps with framed yellow and different green tonalities or either pattern assay. In the second experiment, orientation (north, south, east, and west), distance (0, 20, 40, 60 and 80 cm) from the bed center to the inter-bed space, and height (0, 20, 40, 60 and 80 cm from the bed top) assays were performed in C. annuum var. 'Serrano' (71 +/- 5 cm width and 80 +/- 6 cm height) and 'Caribe' (59 +/- 4 cm width and 64 +/- 7 cm height). No significant difference was detected regardless of orientation. With Serrano, traps at 0 to 60 cm aside and 0 to 40 cm height caught the highest numbers of B. cockerelli and, for Caribe, traps at 0 to 40 cm and 0 to 20 cm, respectively. Placement differences could be due to cultivar traits such as width and height. This study provides new data to improve outdoor monitoring programs for B. cockerelli.
Ground beetles and tiger beetles (Coleoptera: Caraboidea: Carabidae and Cicindelidae) are ecologically important insects that have the potential to provide pest management services in cultivated environments. We investigated the abundance, diversity, and species composition of caraboids in three different ground-cover management environments (herbicide-treated, mowed, and unmanaged) in a north Georgia, USA peach orchard using pitfall traps. Diversity profiles, distance-based redundancy analysis, and indicator species analysis were used to characterize caraboid diversity and species composition and to compare caraboid assemblages in relation to these three ground-cover management strategies. Caraboid abundance was greatest in herbicide-treated plots, but diversity was lowest due to the dominance of the tiger beetle Tetracha carolina (L.), which was a significant indicator species of this habitat. The granivorous ground beetle, Harpalus pensylvanicus (DeGeer), was an indicator species in unmanaged plots, where it was the most abundant species. Overall, species composition differed significantly among treatments, primarily due to differences between herbicide-treated plots and the other two treatments. Our results suggest that peach orchard management practices can have a dramatic effect on caraboid species assemblages, including potentially beneficial entomophagous and granivorous species.
Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is a polyphagous insect pest that is responsible for significant financial losses in important crops. Insect growth regulators (IGRs), such as lufenuron, diflubenzuron, and methoxyfenozide, may function as selective pesticides in an integrated pest management (IPM) program for S. frugiperda and other lepidopteran pests. Thus, this study examined the toxicity and biochemical effectiveness of 3 IGR insecticides against second-instar S. frugiperda larvae in laboratory testing. Furthermore, molecular docking analysis was used to assess each compound's binding to the enzymes glutathione-S-transferase (GST) (PDB ID: 1jlv), a-esterase (PDB ID: 4fng), and acetylcholine esterase (AChE) (PDB ID: 6tt0) to identify the molecular mode of action of the IGRs. Toxicity results indicated that lufenuron and diflubenzuron were the most toxic of the 3 IGRs tested against S. frugiperda, followed by methoxyfenozide, based on the median lethal concentration (LC50) values and 95% confidence interval limits. Furthermore, findings showed that treatment with lethal concentrations (LC50) of methoxyfenozide and lufenuron drastically shortened the duration of the larval and pupal stages of S. frugiperda. Compared to the control group, all tested pesticides had an inhibitory impact on AChE, a-esterase, and GST at 24 and 96 h after treatment. The molecular docking analysis revealed that each IGR tested presented a noteworthy propensity for binding to AchE, a-esterase, and GST, with energy scores varying between-4.927 and-7.115 kcal/mol. In addition to offering more effective pest control options for S. frugiperda, these findings should aid in the advancement of knowledge regarding the biochemical and molecular mechanisms of action of the evaluated IGR insecticides.
DOI: 10.18474/JES25-21 Abstract Sensory neuron membrane proteins (SNMPs) are widely distributed in parasitoid wasps and play a pivotal role in multiple essential activities including feeding, mating, egg laying, and host localizing. In this study, the AoSNMP1 of Anastatus orientalis Yang and Chou (Hymenoptera: Eupelmidae) was cloned by rapid amplification of complementary DNA (cDNA) ends based on the transcriptome data of A. orientalis. The nucleotide and deduced amino acid sequences of AoSNMP1 were analyzed by bioinformatics software. The bioinformatic analysis showed that the full-length cDNA of AoSNMP1 was 1,928 bp (GenBank accession PV545919), with a noncoding region of 211 and 121 bp at the 50and 30 end, respectively. AoSNMP1 contains a 1,596-bp open reading frame encoding 531 amino acids, with a molecular mass of 60.873 kDa and isoelectric point of 5.54. Phylogenetic analysis revealed that the AoSNMP1 of A. orientalis was closely related to the evolution of the SNMP1 in Nasonia vitripennis (Walker). Real-time quantitative polymerase chain reaction indicated that AoSNMP1 is expressed in both male and female adults as well as in various tissues. Notably, expression levels are significantly higher in female adults than in male adults. In addition, the expression level in the abdomen is markedly greater than that in both the head and thorax. This study provides a theoretical basis for further research on the function of AoSNMP1, especially on the olfactory receptive mechanism in A. orientalis.
Two cases of morphological anomalies were documented in natural populations of mosquitoes collected in Yucat & aacute;n, M & eacute;xico. Of the fourth-instar Aedes aegypti (L.) collected, 3.81% (25 of 656) had anomalies that consisted of a chitinized bulb at the end of the siphon. The siphon also displays 2 pectens, 1 in the middle and 1 at the base of the chitinized bulb. The seta 1-S triple developed twice in the siphon, that is, in the middle and distally at the base of the chitinized bulb. Larvae display 2 combs in 2 separate curved rows: 1 in the eighth abdominal segment and 1 in the base of the siphon. The anal segment had double development; the first did not present a saddle and the ventral brushes. The other was less developed displaying a saddle, dorsal brushes, and ventral brushes. One Culex quinquefasciatus Say adult displayed a gynandromorph of the polar type, with the head of a female (filiform antennae, palps shorter than the proboscis), and an abdomen with male genitalia. Phenotypic anomalies in mosquitoes occur in nature, negatively affecting their reproductive success and reducing their vector competence.
The soybean gall midge, Resseliella maxima Gagn & eacute;, emerged as a new species and pest of soybean in the northern Great Plains in 2018. Management tools such as insecticides are largely ineffective because the damaging larval stages, which occur inside a plant stem, are hidden and protected; thus, alternative approaches such as biological control need to be investigated. The purpose of this research was to assess the biological control potential of generalist predators that had not been previously exposed to soybean gall midge and of entomopathogenic nematodes (EPN), which have been shown to infect and kill other gall midge species but have not been evaluated for soybean gall midge. The objectives were (a) to compare soybean gall midge predation rates of three ground-dwelling and three foliar predator species collected from a soybean field without soybean gall midge in bioassays with and without soil and (b) to evaluate the susceptibility of soybean gall midge larvae to four commercially available EPN isolates in the laboratory, each at three inoculation rates. Generalist predators not previously exposed to soybean gall midge consumed 39-98% of larvae within 24 h, although the addition of soil to the bioassay significantly reduced consumption rates for species evaluated in both bioassays. We confirmed that all four EPN species successfully infected and killed larvae, with similar survival rates among EPN species and inoculation rates tested. These results suggest that biological control agents may be a vital component for integrated pest management of soybean gall midge.
Cryptotympana atrata F. (Hemiptera: Cicadidae) is designated as a climate-sensitive indicator insect in South Korea. Notably, C. atrata populations are experiencing significant range expansion in response to rising temperatures, mainly from southern temperate regions, including a southern subtropical remote island, Jeju, to northern cooler areas. Therefore, this study aimed to explore the genetic diversity and structure of C. atrata populations across South Korea using 118 single-nucleotide polymorphisms obtained from direct amplicon sequencing. The most significant genetic differentiation was noted at similar to 100-km distance of the remote Jeju island population from all the inland populations. This signifies the importance of long-standing physical isolation from biogeographic history, rather than ongoing global warming. Within the mainland, only a slight genetic distinction was detected in two of the three newly expanded populations in the northern cooler region, with similar genetic diversity in all inland populations, suggesting that an adaptation to northern lower temperatures was not the major factor facilitating the expansion to new areas. Instead, ongoing global warming seems effective enough to promote the expansion of C. atrata to the northern cooler regions through the facilitated dispersal, exploration of suitable habitats, and success, even under the unfavorable lower temperature conditions in the newly expanded area.
Leptocybe invasa Fisher & La Salle, an invasive pest threatening eucalyptus cultivation worldwide, exhibits remarkable temperature adaptability. Heat shock proteins (HSPs) have been proven to exert a pivotal role in the temperature stress response of insects. However, investigations into the molecular mechanisms underlying the response of L. invasa HSPs to temperature stress remain relatively scarce. In this research, we methodically scrutinized the relative expression levels of 10 HSP genes from the Hsp20, Hsp70, and Hsp90 gene families in adult females and males of L. invasa under various temperature conditions (0, 25, and 40 degrees C) and treatment durations (1, 3, and 5 h) using real-time quantitative polymerase chain reactions. With 25 degrees C as the control temperature, we discerned distinct expression patterns of these HSP genes under 40 and 0 degrees C stress, accompanied by significant sex-specific disparities. Our study further demonstrated that female adults primarily depended on LiHsp20-3 expression to resist thermal stresses, whereas male adults predominantly modulated LiHsp20-1 and LiHsp20-2 at 40 degrees C and LiHsp90-2 at 0 degrees C. These findings highlight the role of HSPs in the response of L. invasa to thermal stress and offer a theoretical foundation for explaining the pest's temperature adaptation.
Illinois corn and soybean farmers have increased their use of cover crops, particularly winter cereals such as cereal rye (Secale cereale L.) and winter wheat (Triticum aestivum L.), as a conservation practice in recent years. Use of a winter cereal cover crop could impact the invertebrate fauna present within a field, including potentially both pest and beneficial species. We assessed insect and slug activity density and injury to the crop in field experiments planted to corn (Zea mays L.) and soybean (Glycine max (L.) Merrill) that had been established to study the impact of cover crops on agronomic management and nutrient loss reduction. A cereal rye cover crop resulted in marginal increases in ground beetle (Coleoptera: Carabidae) and spider (Araneae) activity and a slight decrease in earlyseason injury to soybean. Increased cover crop biomass associated with later termination timings resulted in higher spider activity densities. Slight increases in slug activity were associated with the latest termination of cover crops, but the effect was not consistent at the other termination timings. Neither cover crop presence nor termination timing affected injury to corn; however, in most cases the cover crop was terminated well before corn planting (>= 3-4 weeks). Plant stand was not affected by cover crop treatment at any of our sites. Although care should be taken in drawing broad conclusions, cover crops had a relatively minor impact on economically important insects and other invertebrates in this experiment and reduced injury in one instance.
Understanding morphological variation is crucial for clarifying taxonomic uncertainties and enhancing the identification of economically important pest insects. In this research, geometric morphometrics (GM) was applied to analyze the head and pronotum shape of cryptic species from Pentatomidae), which include significant agricultural pests. By quantifying shape variation, we assessed the efficacy of GM in genus-level discrimination and explored its ability to distinguish morphologically cryptic species within Acrosternum, which are often intercepted in imported commodities outside their native range (Europe and Western Asia). For species level, GM effectively distinguishes 4 frequently intercepted Acrosternum species, emphasizing its applicability in biosecurity. This study highlights GM as a reliable, reproducible, and statistically robust tool for taxonomic resolution, especially in insect groups with subtle morphological differences that are relevant to agriculture and quarantine monitoring.
The termite, Odontotermes formosanus (Shiraki) (Isoptera: Termitidae), is an cescens Bizio SM1 (LT50 = 74.26 h) was combined with 1 mg/mL of RH-5849 (LT50 = (LT50 = 105.21 h), 0.01 mg/mL of indoxacarb (LT50 = 64.89 h), and 0.01 mg/mL of ivermectin (LT50 = 74.66 h), respectively, at the volume ratios of 9:1, 5:1, 1:1, 1:5, and 1:9. Through the analysis of the bioassay results, it was found that when S. marcescens was combined with RH-5849 at the ratios (v/v) of 5:1, 1:1, 1:5 and 1:9 respectively, the co-toxicity coefficients (CTC) were 155.46, 201.41, 234.37, and 148.50, respectively. Similarly, combinations of S. marcescens with buprofezin at the ratios (v/v) of 9:1, 5:1, and 1:1, the CTCs were 135.00, 159.57, and 181.38, respectively, showing synergistic toxicity (CTC > 120) against O. formosanus. Synergistic activity also occurred when S. marcescens was combined with emamectin benzoate at the ratios (v/v) of 9:1, 5:1, 1:1, 1:5, and 1:9 with resulting CTCs of 181.43, 161.47, 178.52, 172.50, and 221.69, when S. marcescens was combined with indoxacarb at the ratios (v/v) of 5:1, 1:1, 1:5, and 1:9 yielding CTCs of 123.81, 158.67, 154.91, and 168.51, and when S. marcescens was combined with ivermectin at the ratios (v/v) of 5:1, 1:5, and 1:9 with CTCs of 123.92, 128.19, and 188.05. These results provide a theoretical basis for management of O. formosanus.
