Polyphagous Pest Research Articles

Sublethal effect and detoxifying metabolism of metaflumizone and indoxacarb on the fall armyworm, Spodoptera frugiperda

The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera, Noctuidae), is a highly polyphagous invasive pest that damages various crops. Pesticide control is the most common and effective strategy to control FAW. In this study, we evaluated the toxicity of metaflumizone and indoxacarb against third-instar FAW larvae using the insecticide-incorporated artificial diet method under laboratory conditions. Both metaflumizone and indoxacarb exhibited substantial toxicity against FAW, with LC50 values of 2.43 and 14.66 mg/L at 72 h, respectively. The sublethal effects of metaflumizone and indoxacarb on parental and F1 generation FAW were investigated by exposing third-instar larvae to LC10 and LC30 concentrations of these insecticides. Sublethal exposure to these two insecticides significantly shortened adult longevity, extended pupal developmental times and led to reduced pupal weight, pupation rates, and adult fecundity in the treated parental generation and F1 generation at LC10 or LC30 concentrations, in comparison to the control group. The larval developmental times were shortened in the parental generation but prolonged in the F1 generation, after being treated with sublethal concentrations of metaflumizone. Furthermore, larvae exposed to LC10 or LC30 concentrations of indoxacarb exhibited elevated activity levels of cytochrome P450 monooxygenase and glutathione S-transferase, which coincides with the observed synergistic effect of piperonyl butoxide and diethyl maleate. In conclusion, the high toxicity and negative impact of metaflumizone and indoxacarb on FAW provided significant implications for the rational utilization of insecticides against this pest.

Feeding ability of the agave weevil Scyphophorus acupunctatus (Coleoptera: Dryophthoridae) on different agave hosts susceptible to infestation

The agave weevil Scyphophorus acupunctatus is a polyphagous pest of agave, yucca and related taxa. Although its many host species differ in their mortality rates, little is known about the factors involved in host selection by the weevil and the defensive response of the infested plants. We compared the suitability of Agave americana subsp. americana, A. americana var. franzosini and A. oteroi as a food source for adult individuals of S. acupunctatus. Feeding rates on leaf samples of the selected taxa were measured under laboratory conditions. The amount of the flavonoids flavone and kaempferol in the leaves was also quantified. The observed consumption rates were significantly lower for A. americana var. franzosini, but only for measurements made on a fresh weight basis and not when consumption was adjusted to leaf dry weight. The leaves of the three agave taxa did not differ in the contents of the two selected flavonoids. We conclude that the three agave taxa are equally suitable as a food source for the weevil, but the observed differences in the consumption of fresh material provides evidence that agaves can differ in the amount of damage caused by the feeding activities of S. acupunctatus.

A multiplex direct PCR method for the rapid and accurate discrimination of three species of spider mites (Acari: Tetranychidae) in fruit orchards in Beijing.

Spider mites (Acari: Tetranychidae) are polyphagous pests of economic importance in agriculture, among which the two-spotted spider mite Tetranychus urticae Koch has spread widely worldwide as an invasive species, posing a serious threat to fruit tree production in China, including Beijing. The hawthorn spider mite, Amphitetranychus viennensis Zacher, is also a worldwide pest of fruit trees and woody ornamental plants. The cassava mite, Tetranychus truncatus Ehara, is mainly found in Asian countries, including China, Korea and Japan, and mainly affects fruit trees and agricultural crops. These three species of spider mites are widespread and serious fruit tree pests in Beijing. Rapid and accurate identification of spider mites is essential for effective pest and plant quarantine in Beijing orchard fields. The identification of spider mite species is difficult due to their limited morphological characteristics. Although the identification of insect and mite species based on PCR and real-time polymerase chain reaction TaqMan is becoming increasingly common, DNA extraction is difficult, expensive and time-consuming due to the minute size of spider mites. Therefore, the objective of this study was to establish a direct multiplex PCR method for the simultaneous identification of three common species of spider mites in orchards, A. viennensis, T. truncatus and T. urticae, to provide technical support for the differentiation of spider mite species and phytosanitary measures in orchards in Beijing. Based on the mitochondrial cytochrome c oxidase subunit I (COI) of the two-spotted spider mite and the cassava mite and the 18S gene sequence of the hawthorn spider mite as the amplification target, three pairs of specific primers were designed, and the primer concentrations were optimized to establish a direct multiplex PCR system for the rapid and accurate discrimination of the three spider mites without the need for DNA extraction and purification. The method showed a high sensitivity of 0.047ng for T. truncatus and T. urticae DNA and 0.0002ng for A. viennensis. This method eliminates the DNA extraction and sequencing procedures of spider mite samples, offers a possibility for rapid monitoring of multiple spider mites in an integrated microarray laboratory system, reducing the time and cost of leaf mite identification and quarantine monitoring in the field.

Importance of core microRNA pathway genes and microRNAs associated with the defense of Odontotermes formosanus (Shiraki) against Serratia marcescens infection

MicroRNAs (miRNAs) are noncoding small regulatory RNAs involved in diverse biological processes. Odontotermes formosanus (Shiraki) is a polyphagous pest that causes economic damage to agroforestry. Serratia marcescens is a bacterium with great potential for controlling this insect. However, knowledge about the miRNA pathway and the role of miRNAs in O. formosanus defense against SM1 is limited. In this study, OfAgo1, OfDicer1 and OfDrosha were differentially expressed in different castes and tissues. SM1 infection affected the expression of all three genes in O. formosanus. Then, we used specific double-stranded RNAs to silence OfAgo1, OfDicer1 and OfDrosha. Knockdown of these genes enhanced the virulence of SM1 to O. formosanus, suggesting that miRNAs were critical in the defense of O. formosanus against SM1. Furthermore, we sequenced miRNAs from SM1-infected and uninfected O. formosanus. 33 differentially expressed (DE) miRNAs were identified, whereby 22 were upregulated and 11 were downregulated. Finally, the miRNA-mRNA networks were constructed, which further suggested the important role of miRNAs in the defense of O. formosanus against SM1. Totally, O. formosanus miRNA core genes defend against SM1 infection by regulating miRNA expression. This study elucidates the interactions between O. formosanus and SM1 and provides new theories for biological control.

Identification and functional characterization of chemosensory genes in olfactory and taste organs of Spodoptera litura (Lepidoptera: Noctuidae).

The tobacco cutworm Spodoptera litura is one of the most destructive polyphagous crop pests. Olfaction and taste play a crucial role in its host plant selection and sexual communication, but the expression profile of chemosensory genes remains unclear. In this study, we identified 185 chemosensory genes from 7 organs in S. litura by transcriptome sequencing, of which 72 genes were published for the first time, including 27 odorant receptors (ORs), 26 gustatory receptors (GRs), 1 ionotropic receptor (IR), 16 odorant-binding proteins (OBPs), and 2 chemosensory proteins (CSPs). Phylogenetic analyses revealed that ORs, IRs, OBPs, and sensory neuron membrane proteins (SNMPs) were mainly expressed in antennae and sequence-conserved among Noctuidae species. The most differentially expressed genes (DEGs) between sexes were ORs and OBPs, and no DEGs were found in GRs. GR transcripts were enriched in proboscis, and the expression of sugar receptors was the highest. Carbon dioxide receptors, sugar receptor-SliuGR6, and bitter GRs-SlituGR43 and SlituGR66 had higher sequence identities between Noctuidae species. CSPs were broadly expressed in various organs, and SlituCSP13 was a DEG in adult antennae. The functional analysis in the Drosophila OR67d expression system found that SlituOR50, a receptor highly expressed in female antennae, is selectively tuned to farnesyl acetate. The results provide a solid foundation for understanding the molecular mechanisms by which chemosensory genes operate to elicit behavioral responses in polyphagous insects.

Performance of Spodoptera litura (Lepidoptera: Noctuidae) in responses to different amplitudes of alternating temperatures across permissive warm temperature regimes.

Climate change involves changes in the pattern of temperature fluctuations and the frequency and magnitude of thermal extremes. It is essential to investigate how insects respond to increased temperature variations, especially for species that usually experience diel temperature variations extending to thermal performance limits. To explicitly elucidate the effects of sizes of amplitudes of temperature variations, we used daily alternating temperatures with an equivalent mean of 28 °C to investigate the impact of different fluctuation amplitudes (± 0 °C, ± 2 °C, ± 4 °C, and ± 6 °C) across permissive temperature regimes on the performance of Spodoptera litura FabriciusFabricius, a highly destructive polyphagous pest of crops and vegetables in tropical and temperate climates. Amplitudes of temperature fluctuations significantly affected developmental durations, adult life spans, pupal weights, fecundity, and fertility of S. litura. The survival rates from the egg stage to the adult eclosion did not differ significantly across different temperature treatments. The developmental durations of individual life cycles significantly increased with larger amplitudes in 3 fluctuating temperature treatments. The pupal weight was significantly lower and the adult life span was significantly shorter in the ± 6 °C treatment in all treatments. Fecundity and fertility were significantly reduced in the ± 6 °C treatment, making the continuation of generations nearly impossible. The results should provide critical information for understanding the ecology of this widespread pest under diel, seasonal, and global climate changes.

Mediterranean fruit fly population phenological patterns are strongly affected by elevation and host presence

The Mediterranean fruit fly (medfly) (Ceratitis capitata, Diptera: Tephritidae), is an extremely polyphagous pest that threatens the fruit production and trading industry worldwide. Monitoring C. capitata populations and analysing its dynamics and phenology is considered of outmost importance for designing and implementing sound management approaches. The aim of this study was to investigate the factors regulating the population dynamics of the C. capitata in a coastal and semi-mountainous area. We focused on effects of topography (e.g. elevation), host presence and seasonal patterns of ripening on the phenological patterns considering data collected in 2008. The experimental area is characterized by mixed fruit orchards, and Mediterranean climate with mild winters. Two trap types were used for population monitoring. The female targeted McPhail type and the male targeted Jackson type. Traps were placed in farms located at different elevations and landscape morphology (coastal and semi-mountainous areas). The main crops included citrus, apples, peaches, plums, pears, figs, quinces and apricots. Adult captures were first recorded in May, peaked in mid-summer and mid-autumn and almost ceased at the end of the season (January 2008). Captures in the coastal areas preceded that of highlands by 15 days. Most of the adults detected during the fruit ripening of late stone fruit cultivars (first peak) and citrus (second peak). The probability of capturing the first adults preceded almost three weeks the peak of adult captures either considering the elevation or host focus analyses. The results provide valuable information on the seasonal population trend of C. capitata in mixed fruit Mediterranean orchards and can support the set-up of IPM systems in areas with various landscapes and different hosts throughout the fruit growing season.

Pathogenicity of Metarhizium rileyi (Hypocreales: Clavicipitaceae) against Tenebrio molitor (Coleoptera: Tenebrionidae).

Tenebrio molitor L., also known as the mealworm, is a polyphagous insect pest that infests various stored grains worldwide. Both the adult and larval stages can cause significant damage to stored grains. The present study focused on isolating entomopathogenic fungi from an infected larval cadaver under environmental conditions. Fungal pathogenicity was tested on T. molitor larvae and pupae for 12 days. Entomopathogenic fungi were identified using biotechnological methods based on their morphology and the sequence of their nuclear ribosomal internal transcribed spacer (ITS). The results of the insecticidal activity indicate that the virulence of fungi varies between the larval and pupal stages. In comparison to the larval stage, the pupal stage is highly susceptible to Metarhizium rileyi, exhibiting 100% mortality rates after 12 days (lethal concentration 50[LC50] = 7.8 × 106 and lethal concentration 90(LC90) = 2.1 × 1013 conidia/mL), whereas larvae showed 92% mortality rates at 12 days posttreatment (LC50 = 1.0 × 106 and LC90 = 3.0 × 109 conidia/mL). The enzymatic analyses revealed a significant increase in the levels of the insect enzymes superoxide dismutase (4.76-10.5 mg-1) and glutathione S-transferase (0.46-6.53 mg-1) 3 days after exposure to M. rileyi conidia (1.5 × 105 conidia/mL) compared to the control group. The findings clearly show that M. rileyi is an environmentally friendly and effective microbial agent for controlling the larvae and pupae of T. molitor.

Pest Status, Damage and Biology of an Invasive Pink Pineapple Mealybug, Dysmicoccus brevipes (Cockrell) (Hemiptera: Pseudococcidae) on Sweet flag (Acorus calamus Linn.): First Report in India

Acorus calamus Linn is a medicinal plant that also has pesticidal properties, primarily against storage pests of agricultural commodities. The creeping rhizomes are the economic part of the plant and are in high demand in Ayurvedic medicine preparation. So far, the pest attacks have not posed a major issue in terms of the economic yield of the plant. In 2022, the presence of an invasive pest, Dysmicoccus brevipes Cockerell, was recorded in the rhizosphere of sweet flag plants maintained at the Pepper Research Station campus, Panniyur, Kannur, Kerala, India. The polyphagous pest has expanded its host range on A. calamus. The pest attack was recorded from February 2022 onwards, which was the world's first report. Its biology was evaluated in the laboratory, and it was found that the pest is a parthenogenetic race with an average life cycle of 59±2.26 days and a fecundity range of 30-74 offspring per adult. Future research should focus on bio-intensive sustainable management packages to protect the IUCN-red list categorized sweet flag from extinction.

Investigation of the synergistic effect of two predatory mites, Phytoseiulus persimilis and Amblyseius swirskii (Acari: Phytoseiidae), in the biological control of Tetranychus urticae (Acari: Tetranychidae)

ABSTRACT Tetranychus urticae (Acari: Tetranychidae) is a polyphagous pest that causes significant economic losses in multiple crop plants. Controlling T. urticae often involves intensive acaricide applications. The use of acaricides also significantly affects human health and ecosystem diversity due to residues and toxic effects in agricultural products. In this study, the efficacy of two predatory mites, Phytoseiulus persimilis and Amblyseius swirskii (Acari: Phytoseiidae), was determined against T. urticae when released as single species and when both species were released together on tomato plants under greenhouse conditions during autumn 2022. The study found that the highest T. urticae density per leaf, with 40.88 ± 0.79 individuals (eggs + motile) in the control group, was reached at the eighth week. In the same week, the highest impact on T. urticae, with 7.57 ± 0.42 individuals (eggs + motile), was observed in the treatment group where P. persimilis + A. swirskii were used together, compared to the untreated. According to the current results, the combined use of two predatory species (P. persimilis and A. swirskii) has been found to significantly suppress the population of T. urticae.

Total synthesis of (6R,12R)-6,12-dimethylpentadecan-2-one, the sex pheromone of Diabrotica balteata LeConte.

Diabrotica balteata LeConte is one of the most important polyphagous agricultural pests. The sex pheromone of this pest was synthesized using Evans asymmetric alkylation, ring-opening reaction of (R)-2-methyloxirane, SN 2 alkylation of secondary tosylate, and coupling of chiral tosylate with Grignard reagent as central strategies. The sex pheromone prepared herein would be useful to control D. balteata.

Trapping strategy and diel periodicity affect capture rate of Halyomorpha halys (Hemiptera: Pentatomidae) in agroecosystems.

The polyphagous pest, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), damages fruit in orchards and field crops and is often found within nearby woodlands. Pheromone-baited traps can be used to monitor H. halys. However, the efficiency of trapping H. halys may vary depending on trapping strategy (live vs. dead capture), location (ground or canopy), and diel periodicity of captures. We compared H. halys capture within fruiting hosts for: (i) live and kill traps on the ground vs. traps in the canopy of black cherry (Prunus serotina Ehrh.) (Rosales: Rosaceae), sugarberry (Celtis laevigata Willdenow) (Rosales: Cannabaceae), and pecan (Carya illinoinensis (Wangenh.) K. Koch) (Fagales: Juglandaceae) trees, (ii) ground and canopy-live traps in sassafras (Sassafras albidum (Nutt.) Nees) (Laurales: Lauraceae), and (iii) whether diel periodicity was detected for live capture in sassafras and cotton. More H. halys adults and nymphs were captured in kill traps than in live traps. More nymphs were captured in kill traps in black cherry and sugarberry on the ground than in the canopy. Live adult capture was significantly greater in sassafras and pecan canopies than on the ground. In cotton and sassafras, more live adults were captured from 8 PM-noon, with the fewest captured from noon-6 PM. A better understanding of stink bug activity in the field allows for improved trapping and, possibly, improved timing of treatment applications.

Susceptibility of Fall Armyworm Field Populations to Vip3Aa/Cry Bt Maize in a Tropical Agricultural Region

Fall armyworm (FAW, Spodoptera frugiperda) is a polyphagous and migratory lepidopteran pest insect in field crops and is notoriously invasive worldwide. In large portions of the Americas, its populations are managed using transgenic maize or cotton varieties producing insecticidal proteins from Bacillus thuringiensis (Bt), primarily Vip3Aa pyramided with Cry Bt proteins. We determined the susceptibility of FAW field populations from locations pressured with such maize hybrids for over five years. We used time–mortality bioassays with F1 third-instar larvae of six geographically distinct populations collected in maize fields of a tropical agricultural region encompassing four Brazilian states. We maintained the neonate progeny from the field populations on an artificial diet until the third instar, and then determined their survival curves on the foliage of three Vip3Aa/Cry-producing Bt maize hybrids. Death of the mid-size, third-instar FAWs occurred relatively rapidly, with larval mortality rates reaching 98–100% in less than five days regardless of Bt maize hybrid. However, median survival time (ST50) for the larvae differed among the populations, with the lowest and highest ST50 values occurring for PI-Cr (42 h, 1.75 d) and PI-Ur populations (66–90 h, 2.75–3.75 h), respectively. Therefore, the F1 third-instar larvae of FAW populations were largely susceptible to Vip3Aa/Cry-producing maize foliage, and the most contrasting susceptibility occurred in the insects from Piauí state, Brazil. These results indicate that progeny of FAWs from areas highly pressured with Vip3Aa/Cry Bt maize hybrids are killed on maize foliage producing Vip3Aa and Cry Bt proteins despite field reports of increased leaf damage by the larvae in some locations. This research informs decision making for Bt-crop resistance management by producers, technicians, and researchers in local, regional, and world agriculture.

Effect of X-ray irradiation on the biological parameters of Xestia c-nigrum.

The sterile insect technique (SIT) is widely used to control Lepidopteran pests by inducing inherited sterility. The noctuid moth Xestia c-nigrum is a polyphagous pest whose subterranean larvae severely injure cereals and some vegetables. The goals of this study were to assess the impact of X-ray irradiation on the development and survival of X. c-nigrum and use the data to select suitable sterilizing doses for potential future use in pest management. Batches of male pupae were exposed to 0 (control), 10, 30, 50, 100, 200, 300, or 400Gy of X-rays, approximately 24h before adult emergence. Exposure of late-stage pupae to 10-200Gy of radiation had no significant effect on adult emergence, but all doses (10-400Gy) reduced adult longevity, the number of spermatophores in mated females, and the number of eggs laid per female in the irradiated parental generation compared with the controls. Exposure to 10 and 30Gy had no significant effects in the F1 generation on 1) the rate of egg hatch, 2) the duration of larval or pupal development, or 3) adult longevity. However, exposure to 50Gy reduced the rate of egg hatch in the F1 generation, and when male pupae were exposed to 100Gy only 1% of the F1 eggs hatched. Also at 100Gy, the developmental durations of larvae and pupae were significantly prolonged, and longevity of adult moths was reduced. There were no significant differences between the control group and any treatments in 1) the sex ratio of the F1 adults, 2) the duration of F1 pre-oviposition or oviposition periods, or 3) the number of eggs laid per F1 female. Our findings indicate that a dose of 100Gy can effectively slow pest development and reduce larval survival in the F1 generation. In addition, F1 adults from lines treated with 100Gy were able to mate and lay eggs, but all F2 eggs failed to hatch. Our results suggest that use of X-ray irradiation has potential to control this polyphagous pest at the regional level.

Pecan, Carya illinoinensis, a New Host Report of Yellowstriped Armyworm, Spodoptera ornithogalli (Guenee) (Lepidoptera: Noctuidae) in the Southeastern US

Yellowstriped armyworm (YSAW), Spodoptera ornithogalli, is a polyphagous pest that infests various crops, including cotton, cabbage, corn, blackberry, grape, etc. We documented egg clusters, larvae and adults of YSAW in pecan orchards in Georgia. Until now, there have been no reports of YSAW infesting pecan and its suitability as a host. To investigate the survival, development, and reproduction of YSAW on pecan, we used the age-stage, two sex life table. The YSAW successfully completed its lifecycle on pecan with an 82% preadult survival rate. The preadult duration and mean fecundity were 47.84 d and 1212.55 offspring per female. The population parameters, including intrinsic rate of increase (r), finite rate of increase (λ), net reproduction rate (R0), and mean generation time (T) were 0.1184 d−1, 1.1257 d−1, 430.67 offspring/female, and 51.05 d, respectively. This study confirms that pecan, Carya illinoinensis, is a potential host plant of YSAW and perhaps more widespread damage could be observed.

Biology of Spodoptera frugiperda (Lepidoptera: Noctuidae) on different types of plants feeds: Potency as a pest on various agricultural plants

Abstract Spodoptera frugiperda is a new invasive and highly polyphagous pest that attacks corn in Indonesia. The availability of abundant plant species allows pests to switch to other host plants to maintain their population. The aim of this research is to examine the development, reproduction, nutritional indices, and life table of S. frugiperda in several plant species. The plants tested were corn, rice, broccoli, oil palm, and baby corn as controls. Ten individual insects were used and the experiments were repeated five times for each plant species. The test results show that different types of plant feed affect the development time, imago life span, fecundity, and fertility of S. frugiperda. Baby corn fruit and broccoli had higher net reproduction value (R 0), intrinsic growth rate (r), gross reproduction rate (GRR), shorter mean generation period (T), and population doubling time (DT) than corn and rice leaves. On oil palm leaf feed, no population parameters could be determined because no larvae developed into adults and had the lowest nutritional indices parameters, so that, oil palm could not be exploited as a host plant. Also, the nutritional indices of several feed plant species tested provided information that broccoli could be the most suitable host compared to other plants tested when there was no corn in the field.

The weak genetic structure of Melolontha melolontha (L.) and Melolontha hippocastani (Fabr.), two important forest pests, indicates their large population sizes and effective gene flow

Abstract Cockchafers Melolontha spp. are polyphagous root pests and outbreak species of considerable economic importance to forestry in Europe. Knowledge of genetic diversity within and between cockchafer populations is largely unexplored but could lead to more effective monitoring and management strategies of these pests. In this study, we fill several gaps in the knowledge of the genetic population structure of Melolontha melolontha and Melolontha hippocastani. Using microsatellite loci and over 200 individuals per species, we examined the genetic structure of Melolontha spp. populations collected from three primary outbreak areas in central and southeastern Poland. We demonstrated that our focal species share some common genetic patterns, such as considerable genetic diversity within subpopulations (within sampling sites) with minor effects of past bottlenecks possibly masked by current population sizes. The estimates of effective population sizes, although subject to wide credibility intervals, indicated a large number of individuals contributing to further generations of the population. The migration rates exceed the threshold of one per generation required for gene flow and maintenance of population equilibrium, indicating limited impact from forest management practices on either cockchafer species. While genetic differentiation was observed in M. melolontha populations, supported by various indices (fixation index, principal coordinate analysis, assignment tests), the M. hippocastani populations were genetically similar. This disparity may hint at the potential historical divergence between these species. In this aspect, more detailed phylogeographic and population genetic studies covering a large area of the Palaearctic distributions of both species are required. Our findings constitute one of the initial efforts aimed at delineating the genetic diversity, differentiation, population structure, gene flow, and migration patterns within Melolontha spp. This exploration is especially significant for M. hippocastani, given its completely unexplored genetic population structure.

Seasonal abundance and trap comparisons of the invasive brown marmorated stink bug Halyomorpha halys (Hemiptera: Pentatomidae) adults from its native region

A challenging, yet fundamental part of initiating effective control measures against an invasive pest species is developing reliable means of monitoring the pest’s seasonal abundance. Halyomorpha halys, a polyphagous insect pest native to East Asia, has become a major economic threat to agricultural systems following unintentional introductions to North America, South America, and Europe. Research involving the seasonal phenology and monitoring attractant preferences of H. halys from its native range remain scarce. An 11-year collection of H. halys monitoring trap data from black light, incandescent light, and methyl (E, E, Z)-2, 4, 6-decatrienoate (MDT) lured traps from three locations in Kyoto, Japan was analyzed to fill gaps in knowledge relating to the native seasonal abundance and effectiveness of diferent trapping techniques for the pest. Due to a high amount of zero trap counts, a zero-inflated approach was taken to analyze the dataset. Overall, H. halys followed a bell-shaped population trend in Kyoto, with abundance peaking in the mid-summer. The attractant preference of H. halys varied slightly with the season, with black light traps producing to highest mean trap counts. The MDT lure traps generated the lowest mean trap counts, but displayed potential use in the reliable detection of early season H. halys. This work is expected to provide greater insight on H. halys in its native range and ultimately help refine existing management programs in invaded regions.

Metabolite profiling and in-silico studies show multiple effects of insecticidal actinobacterium on Spodoptera littoralis

The polyphagous pest, Spodoptera littoralis (Boisduval), poses a significant global economic threat by gregariously feeding on over a hundred plant species, causing substantial agricultural losses. Addressing this challenge requires ongoing research to identify environmentally safe control agents. This study aimed to elucidate the insecticidal activity of the metabolite (ES2) from a promising endophytic actinobacterium strain, Streptomyces sp. ES2 EMCC2291. We assessed the activity of ES2 against the eggs and fourth-instar larvae of S. littoralis through spectrophotometric measurements of total soluble protein, α- and β-esterases, polyphenol oxidase (PPO), and catalase enzyme (CAT). The assessments were compared to commercial Biosad® 22.8% SC. Untargeted metabolomics using LC-QTOF-MS/MS identified 83 metabolic compounds as chemical constituents of ES2. The median lethal concentration (LC50) of ES2 (165 mg/mL) for treated Spodoptera littoralis eggs showed significant differences in polyphenol oxidase and catalase enzymatic activities, while the LC50 of ES2 (695 mg/mL) for treated S. littoralis fourth instar larvae showed lower significance in α- and β-esterase activities. Molecular docking of ES2 identified seven potent biocidal compounds, showing strong affinity to PPO and catalase CAT proteins in S. littoralis eggs while displaying limited binding to alpha and beta esterase proteins in the larvae. The results contribute to the understanding of ES2 as a promising alternative biopesticide, providing insights for future research and innovative applications in sustainable pest management strategies.

Monitoring adult Delia platura (Diptera: Anthomyiidae) in New York State corn fields using blue and yellow sticky cards

Abstract The seedcorn maggot, Delia platura (Meigen; Diptera: Anthomyiidae), is a polyphagous pest that feeds on decaying organic matter, seeds, and seedlings of several crops, including corn (Zea mays L.; Poaceae). In corn and soybeans, D. platura is a sporadic pest. To make recommendations as to which sticky trap color is more effective at trapping D. platura, we sampled 52 corn fields in four regions across New York State with blue and yellow sticky cards. More adults were caught with blue (77.6 %) than yellow cards (22.4 %). The same pattern was observed when all individuals were combined and separated by females and males. The higher captures with blue sticky cards were consistent across space and time, indicating the effectiveness of trapping adults and monitoring them at a regional scale.