Important Pest Research Articles

Tetranychus urticae Koch Biology on Apple Trees

The two-spotted spider mite (Tetranychus urticae Koch) is a polyphagous arthropod herbivore that consumes over 1,100 plant species from 140 distinct plant families, including those producing harmful chemicals in temperate and tropical climates. It is an important pest in greenhouse and field cultivation, causing damage to various crops such as citrus, apples, grapes, tomatoes, peppers, cucumbers, strawberries, maize, and soy. T. urticae ability to spread over agricultural fields and adapt to environmental stressors is linked to its high propensity for mutation, leading to the highest frequency of pesticide resistance among arthropods. The genetic diversity of T. urticae gathered from apple orchards throughout Poland has been studied to investigate potential correlations between molecular variations and the occurrence of resistance to METI-acaricides. Research has shown that an abundance of leaf pubescence on the abaxial leaf surface adversely affects the development of European red mite, two-spotted spider mite, and carmine spider mite. However, due to variations in leaf sizes, tree canopy, tree ages, and the existence of natural enemies, it is impossible to compare data gathered due to variations in leaf sizes, tree canopy, tree ages, and the presence of natural enemies. Pesticide treatments negatively impact fruit plantations' ecosystems, devastating biodiversity, altering the makeup and structure of arthropod populations, and promoting mass reproduction of phytophage mites by displacing certain species with others. The most extensive research has been done on the common spider mite's development of resistance to avermectin group preparations, with some studies showing resistance to multiple acaricides.

Investigation of resistance ratios and resistance mechanisms of Cydia pomonella (L.) (lepidoptera: Tortricidae) populations collected from apple orchards in Isparta (Türkiye) against some insecticides

The codling moth, Cydia pomonella is an important pest that causes significant economic losses in apples and walnuts in the world. The aim of this study was to investigate, for the first time in Türkiye, the resistance status and resistance mechanisms of codling moth, Cydia pomonella against indoxacarb, deltamethrin and emamectin benzoate. All apple orchard populations developed resistance ratios ranging from 3.38 to 22.37-fold to deltamethrin, 5.67–29.87-fold to indoxacarb and 1.46–3.05-fold to emamectin benzoate. The interaction of some synergists triphenyl phosphate (TPP), piperonyl butoxide (PBO) and diethyl maleate (DEM) with indoxacarb and deltamethrin was analyzed in the susceptible, MAREM and Tepeli populations with moderate resistance to indoxacarb and deltamethrin. While indoxacarb + TPP showed a significant synergistic effect only in MAREM population, a significant synergistic effect was observed with indoxacarb + TPP and indoxacarb + PBO in Tepeli population. The activities of detoxifying enzymes [esterase, glutathion –S– transferase (GST) and cytochrome P450 monooxygenase (P450)] studied by biochemical methods showed some variation depending on the population. The results of biochemical analyses showed that esterase and GST enzyme activities of all populations was between 0.51 and 0.94, 0.77 and1.29 mOD min−1mg−1 proteins, respectively. The P450 enzyme activities ranged from 0.53 to 0.78, RFU min−1mg−1 proteins. In addition, the L1014F knockdown mutation (CTT to TTT) corresponding to leucine to phenylalanine amino acid substitution of the voltage-gated sodium channel in Cydia pomonella was determined in MAREM and Tepeli populations. It was determined that while MAREM and Tepeli populations developed moderate resistance, the other populations developed a low level resistance to deltamethrin and indoxacarb. On the other hand, all populations developed a low level resistance to emamectin benzoate. The P450 and esterase enzyme activities were significantly higher in MAREM and Tepeli populations which were resistant to deltamethrin and indoxacarb than the susceptible population. In addition, a Kdr point mutation L1014F was detected in the deltamethrin resistant MAREM and Tepeli populations.

Occurrence, distribution and description of Harmonia dimidiata (Fabricius), a predacious Coccinellid from West Bengal, India

Aim: To provide information about the occurrence and distribution of Harmonia dimidiata from West Bengal and facilitate the identification of species based on morpho-taxonomy. Methodology: Survey was done in different agro-climatic zones of West Bengal. Specimens were procured from their associated host plants, brought to the laboratory and investigated for taxonomic characters. Results: The morpho-taxonomy of H. dimidiata, as well as its host record, and distribution, were fully explained in the present investigation. It is most common in hill, terai, and old alluvial zone of West Bengal. They have been observed preying on Rhopalosiphum maidis (Fitch) in corn and Aphis gossypii (Glover). Interpretation: H. dimidiata population were recorded during survey from four different agro-climatic zones of West Bengal. They were observed to be preyed upon A. gossypii and R. maidis. The information about the biodiversity of H. dimidiata and their role as predator of numerous agriculturally important crop pests are extremely valuable that enrich our knowledge and immensely help in devising a pest management programme considering them as an important biocontrol agent. Furthermore, research on their biodiversity aids in learning about the predaceous behaviour in connection with the pest and crop populations, their reproduction and occurrence. This information is indeed praiseworthy while exploiting the ladybird species, H. dimidiata for a commercial biocontrol operation. Key words: Coleoptera, Coccinellidae, Harmonia dimidiata, Predaceous, West Bengal

Histological Investigations on Potato Tuber Moths, Phthorimaea operculella Treated with a Botanical Extract of Basil (Ocimum basilicum L), with Particular Attention to the Alterations in the Ultrastructure of the Larval Digestive Tract

Background: Phthorimaea operculella (Zeller), the potato tuber moth (PTM) is one of the most important pests that attacks potato, Solanum tuberosum L. crops worldwide. Adult moths attack tubers in fields as well as in storage. Infested tubers become unsuitable for trade or consumption, the tuber damage increases gradually after several generations of the pest during storage time. Botanicals have been found to be an efficient control method especially when they act as antifeedant or repellent, or even stomach poisons. The estimation of the mortal impact of some extracts against PTM was examined by emphasizing the Ultrastructure changes in the larval digestive tract by using scanning and transmission electron microscope. Results: Structural changes throughout the entire digestive tract (Fore-, Mid- and Hind-gut), induced by Basil extract were detected through both microscope, these changes leading lastly to the death of the treated larvae. Many different ruptures and malformations were detected throughout all the digestive tract assessment. Conclusions: Studies of the occurred changes revealed some histopathological changes through out all the digestive tract (Fore-, Mid- and Hind-gut), the attached muscular layer, tracheal system, and visceral fat bodies of the larvae when fed with tubers treated with Basil extract. From this findings, the use of plant extracts can be recommended for protection of potato tuber against the infestation by the tubers moths.

A Review of Biological Control One Decade After the Sorghum Aphid (Melanaphis sorghi) Outbreak.

Melanaphis sorghi is a pest that is native to Africa but is now distributed worldwide. In 2013, its destructive capacity was demonstrated when it devastated sorghum crops in the United States and Mexico, making it a new pest of economic importance in North America. At the time, the phytosanitary authorities of both countries recommended the use of pesticides to control the outbreak, and biological control products for the management of this pest were not known. In response to the outbreak of M. sorghi in North America, several field studies have been performed in the last decade on sorghum crops in the USA and Mexico. Works have focused on assessing resistant sorghum hybrids, pesticide use, and recruitment of associated aphid predators and entomopathogens for natural control of M. sorghi populations. The objective of this review is to compile the information that has been generated in the past decade about indigenous enemies affecting M. sorghi naturally in the field, as well as the search for biological control alternatives and evaluations of interactive effects of resistant sorghum hybrids, pesticides, and natural enemies. To date, different predators, parasitoids, fungi, and bacteria have been evaluated and in many cases found to affect M. sorghi populations in sorghum agroecosystems or laboratory bioassays, and the use of resistant sorghum varieties and pesticides did not have clear toxic effects on natural enemy populations. Many of the macroorganisms and microorganisms that have been evaluated as potential biological controls have shown potential as alternatives to synthetic pesticides for keeping M. sorghi population densities below economic damage thresholds and are compatible with integrated management of sorghum aphids. While most tests of these biological alternatives have shown that they have aphidicidal potential against sorghum aphids, it is crucial to take into account that their effectiveness in the field depends on a number of abiotic and biotic factors, including soil texture, temperature, humidity, and natural enemies.

Effects of High-Temperature Stress on Biological Characteristics of Coccophagus japonicus Compere.

The parasitoid, Coccophagus japonicus Compere (Hymenoptera: Aphelinidae) is a dominant natural enemy of Parasaissetia nigra Nietner (Hemiptera: Coccidae), an important pest of rubber trees. Much of Chinese rubber is cultivated in hotter regions such as Yunnan and Hainan, exposing applied parasitoids to non-optimal temperatures. Therefore, C. japonicus must adapt to avoid temperature-related impacts on survival and population expansion. In this study, we monitored the survival rate, developmental duration, parasitism rate, and fecundity of C. japonicus during short-term exposures to 36 °C, 38 °C, and 40 °C for 2, 4, and 6 h, as well as continuous exposures to 32 °C and 34 °C for 3 days. The results show that short-term exposure to high-temperature stress leads to decreased survival rate of C. japonicus larvae and pupae, with survival rates declining as temperature and duration increase. High-temperature stress also delayed insect development, reduced mature egg production, shortened the body length of newly emerged females, and decreased female lifespans. Moreover, continuous high-temperature stress was found to significantly impact the development and reproduction of C. japonicus. Compared with the CK (27 °C), 3 d of continuous exposure to 34 °C prolonged developmental duration, shortened the body length and lifespan of newly emerged females, reduced survival rate and single female fecundity, and significantly decreased offspring numbers and parasitism rates. Temperatures of 36 °C, 38 °C, and 40 °C decreased the mortality time of adult females to 28.78, 16.04, and 7.91 h, respectively. Adverse temperatures also affected the insects' functional response, with 8 h of stress at 36 °C, 38 °C, and 40 °C causing the control efficiency of C. japonicus on P. nigra. This level of stress in the parasitoids was found to reduce the immediate attack rate and search effect, prolong processing time, and attenuate interference between small prey. Parasitoid efficiency was lowest following exposure to 40 °C. In this study, we determined the range of high temperatures that C. japonicus populations can tolerate under short- or long-term stress, providing guidance for future field applications.

RNAi of nuclear receptor E78 inhibits the cuticle formation in the molting process of spider mite, Tetranychus urticae.

The two-spotted spider mite, Tetranychus urticae, is an important pest mite in agriculture worldwide. E78, as a member of the nuclear receptor superfamily and a downstream responsive gene of ecdysteroids, plays a crucial role in regulating physiological behaviors such as development and reproduction in insects. However, its function in mites remains unclear. The aim of this study was to explore how E78 functions in the molting process of spider mites. In this study, reverse transcription quantitative polymerase chain reaction (RT-qPCR) experiments to analyze the expression pattern of TuE78 during the development of Tetranychus urticae, demonstrated that the expression level of TuE78 was higher during the molting state than that after the completion of molting, and it reached a peak expression level when the deutonymph mites entered the molting stage. RNA interference (RNAi)-mediated gene-silencing of TuE78 resulted in 95% deutonymph mite molt failure. A series of analysis under a light microscope, and scanning and transmission electron microscopy revealed that RNAi mites died within the exuvium without ecdysis, and that apolysis had started but the new cuticle was thin and the typical cuticular lamellae were absent, indicating blockage of the post-apolysial processes and explaining molt failure. Hence, transcriptome sequencing confirmed that the expression of cuticle protein and lipid metabolism-related genes was significantly affected after TuE78 silencing. This study demonstrated that TuE78 participates in the molting process of Tetranychus urticae by regulating the post-apolysial processes with the formation of new cuticle and successful ecdysis. This in turn suggests the potential of TuE78 as a target for pest mite control and provides a theoretical basis for further exploration of the molecular regulatory mechanism of spider mite molting. © 2024 Society of Chemical Industry. Published by John Wiley & Sons Ltd.

Prevalence and abundance of plant-parasitic nematodes associated with corn (Zea mays L.) in Anuradhapura, Sri Lanka  

Plant parasitic nematodes (PPN) are important pests of corn (Zea mays L.) Globally, while corn production has recently expanded in Sri Lanka. The population abundance, distribution, and pathological effects of nematodes that adversely affect corn production in Sri Lanka are poorly understood. This study was conducted to identify the prevalence of major PPN genera, population abundance, and their reproduction associated with corn fields in the Anuradhapura district. Over 92% of the corn fields were positive for PPN from the fields sampled in February 2021. Major PPN genera identified were Pratylenchus (71.4%) Helicotylenchus (28.6%), Meloidogyne (21.4%), Criconemella (21.4%), and Hoplolaimus (35.7%). The mean population of the Pratylenchus was 2020 kg-1 of soil, which was above the threshold level (1000 Pratylenchus kg-1 of soil), while other genera were lower than the threshold. All genera, except Meloidogyne, were observed from the intensive sampling from the selected fields during the next cropping season from November 2021 (seedling stage) to February 2022 (harvesting stage). Pratylenchus abundance in all the fields was lower than the threshold at the seedling stage and it was 2 to 10 times higher during the harvesting stage, except in Kelenikawewa where the initial Pratylenchus population (1865 kg-1 of soil) was also above the threshold. According to our results, Pratylenchus have the potential to impact corn yield in Anuradhapura. Future field experiments will determine the impact of PPN on corn production in Sri Lanka.

First record of Monalonion velezangeli (Hemiptera: Miridae) affecting avocado and cherimoya (Annona cherimola) as new hosts in Ecuador

Monalonion velezangeli is a polyphagous hemipteran reported as one of the main pests of economic importance in avocado and coffee crops. This is the first report of M. velezangeli affecting avocado (Persea americana (Mill)) in Ecuador and the first report of cherimoya (Annona cherimola) as a new host plant. The species was identified through classical taxonomy based on morphology, with parallel molecular identification targeting the cytochrome oxidase I region.

Marking Helicoverpa zea (Lepidoptera: Noctuidae) with fluorophores for use in mark-release-recapture research

Abstract Knowledge of insect dispersal and long-distance migratory flight capacity and patterns represent key factors needed for risk assessment of invasive pest species, insecticide resistance management, and more effective pest control. Having operative tools to both mark and track insect pest movement is therefore critical to achieving such goals. Here, we describe a new procedure for marking Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), one of the most economically important crop pests in the United States. Adult H. zea moths were effectively marked using the liquid fluorophore cartax green, a persistent UV-fluorescent pigment, both directly by topical application and indirectly by briefly submerging pupae in the marking solution prior to adult emergence. Regardless of the application method, the cartax mark was retained on the moths throughout their entire adult lifespan. No mortality differences were observed between cartax green-marked and water-marked (control) moths. Additionally, using rotary flight mills, we found no significant differences in several flight parameters, including total number of flights, flight speeds, flight distances, or flight durations between unmarked and cartax-marked moths. Under laboratory conditions, we did observe the lateral transfer of different colored fluorophores between moths, indicating that undesirable marking could potentially occur. Moreover, we found that not all fluorophores were equally retained on H. zea moths, with cartax green remaining intact on moths longer than did a corresponding magenta fluorophore. The results show that cartax green fluorophore could be a practical marker for H. zea and other holometabolous species targeted for large-scale mark-release-recapture research.

Characterisation of the bacteriomes harboured by major wireworm pest species in the Canadian Prairies.

Nearly all insects harbour bacterial communities that can have a profound effect on their life history, including regulating and shaping host metabolism, development, immunity and fitness. The bacteriomes of several coleopterans have been described; however, very little has been reported for wireworms. These long-lived larvae of click beetles (Coleoptera: Elateridae) are major agricultural pests of a variety of crops grown in the Canadian Prairies. Consequently, the goal of this study was to characterise the bacteriomes of five of the most significant pest species within the region: Limonius californicus, Hypnoidus abbreviatus, H. bicolor, Aeolus mellillus and Dalopius spp. To do this, we collected larvae from southern Manitoba fields (pre-seeding) and carried out 16S rRNA sequencing on individual specimens. Our results indicate wireworms have diverse and taxon-rich bacterial communities, with over 400 genera identified predominately from the phyla Proteobacteria, Actinobacteriota, Bacteroidota and Firmicutes. However, each species had nine or fewer genera comprising >80% of their bacteriome. Network analyses revealed some community structuring consistent among species, which may culminate in shaping/regulating host biology. Moreover, the microbial signatures were influenced by both ontogeny (early vs. late stage larvae) and reproductive strategy (sexual vs. parthenogenetic), with a myriad of other factors likely contributing to bacterial diversity that are impossible to resolve from our study. Overall, this metagenomics study represents the first to characterise the bacteriomes of wireworms in the Canadian Prairies and the findings could assist in the development of sustainable management strategies for these important agricultural pests.

V1848I Mutation in the Voltage-Gated Sodium Channel Confers High-Level Resistance to Indoxacarb and Metaflumizone in Spodoptera exigua.

Spodoptera exigua is one of the most serious lepidopteran pests of global importance. With the intensive use of insecticides, S. exigua has evolved resistance to many insecticides, including the sodium channel blocker insecticides (SCBIs) indoxacarb and metaflumizone. In this study, we investigated the role of the V1848I mutation in the voltage-gated sodium channel (VGSC) in SCBI resistance and its inheritance patterns in S. exigua through the development and characterization of a near-isogenic resistant strain. The AQ-23 strain of S. exigua, collected in 2023 from Anqing, Anhui province of China, shows 165-fold resistance to indoxacarb compared with the susceptible WH-S strain. A frequency of 44.6% for the V1848I mutation was detected in the SeVGSC of the AQ-23 strain, while no F1845Y mutation was found. Through repeated backcrossing and marker-assisted selection, the V1848I mutation in the AQ-23 strain was introgressed into the susceptible WH-S strain, creating a near-isogenic strain named WH-1848I. This WH-1848I strain exhibits high levels of resistance to indoxacarb (146-fold) and metaflumizone (431-fold) but remains susceptible to broflanilide and spinosad compared with the WH-S strain. Inheritance analysis revealed that SCBI resistance in the WH-1848I strain is autosomal, nonrecessive, and genetically linked to the V1848I mutation. These findings establish a clear link between the V1848I mutation and SCBI resistance in S. exigua, offering valuable insights for developing molecular detection tools and resistance management strategies.

Mitochondrial DNA sequence-based identification of two subterranean termite species, from Riyadh Province, Kingdom of Saudi Arabia.

Termites are economically important wood-destroying and agricultural pests. The termite fauna almost consists of 2900 described species in 286 genera worldwide. In the present study, hundreds of termite samples from 42 different locations in the Riyadh province were collected. These samples were previously used for morphometric identification and reported two subterranean termite species, Coptotermes heimi and Psammotermes hypostoma, in the family Rhinotermitidae. In the present study, these samples were analysed using DNA barcoding with the mitochondrial cytochrome c oxidase subunit 1 gene to confirm the conventional taxonomical identification on a molecular basis. The obtained COI gene sequences of all 42 termite specimens were submitted to GenBank (accession numbers: ON529959-ON529969, OP825131-OP825132, and OP890882-OP890910). Eleven of the 42 samples were thus identified as C. heimi and the remaining 31 samples as P. hypostoma, which were phylogenetically analysed. All the 11 C. heimi sequences were grouped in a single clade, indicating close relatedness. While 31 sequences of P. hypostoma constituted two clades in the phylogenetic tree. Pairwise nucleotide sequence identity and divergence analysis showed that C. heimi sequences showed high nucleotide identities of 87.6-99.5% and less divergence ranging from 0.5% to 13.6%. Similarly, sequences of P. hypostoma also showed high nucleotide identity of 78.6-100% and low divergence among them ranging from 0-10.7%. A further application, significance, and shortcomings of COI-based DNA barcoding have been discussed. DNA barcoding using the COI gene is a reliable tool to distinguish C. heimi and P. hypostoma genotypes.

First Report of Dalbulus maidis (DeLong and Wolcott) (Hemiptera: Cicadellidae) in Oklahoma.

The corn leafhopper, Dalbulus maidis (DeLong and Wolcott) (Hemiptera: Cicadellidae), is an invasive insect that can cause damage to maize (Zea mays L.) in two ways: by direct feeding and the transmission of several plant pathogens. Dalbulus maidis is an invasive and serious economic pest of maize that has spread from its center of origin in Mexico to the southernmost parts of the United States. Prior to 2024, corn leafhoppers had not been documented in Oklahoma, and their spread northward toward the United States corn belt is of significant concern. Here, we provide the first reports of the insect in maize in several Oklahoma counties. Insect specimens were collected at various commercial and experimental field sites by Oklahoma State University research and extension personnel. The identity of the insect species was validated through morphological and molecular taxonomy. The presence records for the corn leafhopper presented here provide valuable information for future monitoring and management efforts of this economically important pest and disease.

A Review of the Arrival, Effects, and Management of Bagrada hilaris in South America: The Case of Chile

Biological invasions are partly defined by their ability to spread rapidly within invaded regions, posing threats to biodiversity and local species assemblages. The painted bug, Bagrada hilaris (Hemiptera, Pentatomidae) (Burmeister, 1835), originally described as being from India, is an important pest worldwide, mainly due to the serious economic losses incurred and the large number of zones invaded. Since its initial detection in Chile in 2016, the invasive and destructive paint bug has started its invasion to the east and invaded new areas in South America. Without adequate control methods, the insect may threaten brassica crop production, resulting in yield losses greater than 70% in recently infested areas. The extraordinarily wide range of the B. hilaris invasion has necessitated studies describing its biology and ecology, as well as highlighting the urgent need for effective and long-term management techniques. Hence, thoroughly revising the data on this pest in new areas that have been invaded, as well as in the area of origin, is expected to enable the development of management programs. This review incorporates information on B. hilaris in South America, including the invasion, ecology, and potential management approaches, which may allow for efficient integrated pest management, mainly in Chile. Lastly, researchers are expected to break the bottlenecks of some key issues, offering valuable perspectives for identifying strategies that warrant additional research as potential biological control agents for B. hilaris in South America, utilizing either augmentative or conservation biological control approaches, as well as semiochemicals and cultural practices.

A diagnostic gap to fill: Development of molecular tools to distinguish the cyst-forming nematode species Heterodera carotae and Heterodera cruciferae

The carrot cyst nematode, Heterodera carotae, is an important pest causing qualitative and quantitative production losses across several countries worldwide. In culture crops, Heterodera carotae and Heterodera cruciferae, can be found in mixture and are virtually unrecognizable from a morphological point of view. However, only H. carotae is able to develop on carrot. To monitor carrot production and set up suitable H. carotae control plans, simple and reliable diagnostic methods to detect and identify these two species are needed. In this study, we developed and successfully tested two real-time PCR protocols (SYBR Green singleplex and TaqMan multiplex real-time PCRs) against both species: H. carotae and H. cruciferae. Using two specific sets of primers, we managed, whatever the methods, to distinguish the two species. Moreover, we showed a higher specificity using the TaqMan assays but a better sensitivity with the SYBR Green assays. In this study, we are proposing two useful and reliable diagnostic tools to enable farmers and scientists to rapidly detect two morphologically and genetically closely related species and supervise agricultural management.

Weather Based Forewarning Systems for Important Pests and Diseases in Major Crops

In present - day agriculture, weather based forewarning systems have become a vital tool in combating pests and diseases. These systems forecast the occurrence and severity of important insect pests and diseases using the meteorological data provided. The data regarding important meteorological variables like temperature, rainfall, humidity, wind speed, and wind patterns are integrated in these systems. As forewarning systems use highly developed artificial intelligence technology, historical data analysis and pest-weather correlations to provide precise and timely insights to the farmer community, which enable them to take appropriate control measures when required and help in reducing crop losses and optimising the pesticide usage. These will help to schedule pesticide applications as needed, ultimately reducing the quantity of pesticides sprayed and their detrimental impact on the environment and other beneficial organisms and increasing the overall agricultural output, which is very important in sustainable agriculture. To unlock the full potential of these systems, issues regarding data availability, localizing the systems to particular regions, and the effects of climate change should be addressed.

Volatiles potentially useful to be used as biomarkers for monitoring the khapra beetle Trogoderma granarium for quarantine

The khapra beetle, Trogoderma granarium, is one of the most important quarantine pests globally. In order to identify potential biomarkers for establishing a rapid and effective monitoring technology for T. granarium quarantine, headspace-solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrum (GC-MS) was used to identify volatiles that are potentially useful for early detection of the presence of the T. granarium presence. Three volatiles, including Ethyl palmitate, (Z)-5-tetradecenoic acid and (Z)-14-methyl-8-hexadecen-1-al, were commonly identified as unique volatiles emitted from four different stored products including peanut, barley, wheat and rapeseed only after T. granarium infestation. In addition, four volatiles including hexadecane, palmitic acid, (Z)-14-methyl-8-hexadecen-1-al and N-heptadecane, were found emitted commonly from the larvae of T. granarium after they fed on the four stored products. These common chemicals could potentially be biomarkers sensitive enough for monitoring the presence of T. granarium. In addition to these unique chemicals, a combination of up- and down-regulated volatiles by each type of stored seeds were also identified as potential markers useful for the early detection of the presence of T. granarium. Our results could be a first step towards establishing a method for T. granarium monitoring and quarantine.

Chromosome-scale genome of the polyphagous pest Anastrepha ludens (Diptera: Tephritidae) provides insights on sex chromosome evolution in Anastrepha.

The Mexican fruit fly, Anastrepha ludens, is a polyphagous true fruit fly (Diptera: Tephritidae) considered one of the most serious insect pests in Central and North America to various economically relevant fruits. Despite its agricultural relevance, a high-quality genome assembly has not been reported. Here, we described the generation of a chromosome-level genome for the A. ludens using a combination of PacBio high fidelity long-reads and chromatin conformation capture sequencing data. The final assembly consisted of 140 scaffolds (821 Mb, N50 = 131 Mb), containing 99.27% complete conserved orthologs (BUSCO) for Diptera. We identified the sex chromosomes using three strategies: 1) visual inspection of Hi-C contact map and coverage analysis using the HiFi reads, 2) synteny with Drosophila melanogaster, and 3) the difference in the average read depth of autosomal versus sex chromosomal scaffolds. The X chromosome was found in one major scaffold (100 Mb) and eight smaller contigs (1.8 Mb), and the Y chromosome was recovered in one large scaffold (6.1 Mb) and 35 smaller contigs (4.3 Mb). Sex chromosomes and autosomes showed considerable differences of transposable elements and gene content. Moreover, evolutionary rates of orthologs of A. ludens and Anastrepha obliqua revealed a faster evolution of X-linked, compared to autosome-linked, genes, consistent with the faster-X effect, leading us to new insights on the evolution of sex chromosomes in this diverse group of flies. This genome assembly provides a valuable resource for future evolutionary, genetic, and genomic translational research supporting the management of this important agricultural pest.

The grasshopper arcyptera (Pararcyptera) meridionalis ikonnikov (Insecta, orthoptera) as a possible agricultural pest in temperate Asia

The goal of the article is to estimate possible changes of the distribution of Arcyptera meridionalis in the contemporary and potential future climatic conditions. The data were collected during field trips. Two packages to produce the species distribution models, namely MaxEnt and ellipsenm, were used. The generated models predict that the status of A. meridionalis as the important pest will not change significantly in the nearest future, however, in the middle of this century, its distribution patterns will become more complicated. The areas those will be the most suitable for the species will remain mainly in the western and central parts of its range. The harmful activity of A. meridionalis can be especially important due to its early hatching, because hoppers may damage and destroy shoots with first leaves and tillers. The models generated for A. meridionalis look like quite different from the models for other steppe acridids. On the contrary, some resemblance between forecasts for two harmful, but quite different grasshopper species, namely Siberian-Mongolian A. meridionalis and East-Mediterranean A. labiata, are revealed. The models for both species demonstrate some possible significant depletion of the territories with suitable conditions for each one in the second half of the 21st century.