Maruca Vitrata Research Articles

Impact of Key Insect Pests on Cowpea and their Relationship with Weather Parameters

Introduction: Cowpea (Vigna unguiculata L.) is a vital pulse crop with substantial nutritional value in India that faces production challenges due to various biotic and abiotic factors. Among the biotic factors that affects cowpea, pests such as Maruca vitrata and Riptortus pedestris significantly impact cowpea yields. This study aimed to evaluate the seasonal incidence of these pests and analyze their correlations with weather parameters in Thiruvananthapuram, Kerala. Methodology: Field observations were conducted over the cropping season to record pest populations across Standard Meteorological Weeks (SMWs). The population of the pod bugs and pod borers were taken from five plants. Statistical analyses were performed to identify correlations between pest incidence and key weather factors. Key Findings: The incidence of R. pedestris peaked in the 16th SMW, reaching 7.54 bugs per five plants. This pest displayed a significant positive correlation with maximum temperature (r = 0.637) and minimum temperature (r = 0.559) and a negative correlation with evening relative humidity (r =-0.480). Similarly, M. vitrata larval populations peaked during the same period at 2.65 larvae per five plants, showing a similar temperature-dependent correlation. Implications: The temperature-sensitive incidence patterns observed underscore the need for integrated pest management (IPM) strategies that address climatic factors to enhance cowpea sustainability. This data provides valuable insights for future pest forecasting and management efforts.

Sympatric diversity pattern driven by the secondary contact of two deeply divergent lineages of the soybean pod borer Leguminivora glycinivorella.

The soybean pod borer, Leguminivora glycinivorella (Matsumura), is an important tortricid pest species widely distributed in most parts of China and its adjacent regions. Here, we analyzed the genetic diversity and population differentiation of L. glycinivorella using diverse genetic information including the standard cox1 barcode sequences, mitochondrial genomes (mitogenomes), and single-nucleotide polymorphisms (SNPs) from genotyping-by-sequencing. Based on a comprehensive sampling (including adults or larvae of L. glycinivorella newly collected at 22 of the total 30 localities examined) that covers most of the known distribution range of this pest, analyses of 543 cox1 barcode sequences and 60 mitogenomes revealed that the traditionally recognized and widely distributed L. glycinivorella contains two sympatric and widely distributed genetic lineages (A and B) that were estimated to have diverged ∼1.14 million years ago during the middle Pleistocene. Moreover, low but statistically significant correlations were recognized between genetic differentiation and geographic or environmental distances, indicating the existence of local adaptation to some extent. Based on SNPs, phylogenetic inference, principal component analysis, fixation index, and admixture analysis all confirm the two divergent sympatric lineages. Compared with the stable demographic history of Lineage B, the expansion of Lineage A had possibly made the secondary contact of the two lineages probable, and this process may be driven by the climate fluctuation during the late Pleistocene as revealed by ecological niche modeling.

EpOME mediates the immune resolution and its alkoxide analog enhances the virulence of microbial insecticides against the legume pod borer, Maruca vitrata

Excessive and unnecessary immune responses cause serious adverse effects due to self-tissue damage and energy consumption, particularly at the late stage of infection to terminate the induced immunity. Unlike mammals, which use long-chain fatty acid oxylipins, C18 oxygenated polyunsaturated fatty acids are suggested to act as immune resolvins in insects, including two epoxyoctadecamonoenoic acids (9,10-EpOME and 12,13-EpOME). This study investigated the physiological roles of EpOMEs in immune resolution in the lepidopteran insect, Maruca vitrata. The levels of two EpOMEs in the larvae increased during the late infection stage upon immune challenge. At their peak concentrations at 96 h post-infection (pi), both EpOMEs were found at similar levels: 323.18 pg/mg body weight for 9,10-EpOME and 322.07 pg/mg body weight for 12,13-EpOME. Both EpOMEs inhibited cellular and humoral immune responses, with 12,13-EpOME being more potent than 9,10-EpOME. Genes associated with EpOME synthase and degradation, identified as Mv-CYP1 and Mv-sEH, were detected in various developmental stages and tissues of M. vitrata. RNA interference (RNAi) targeting Mv-CYP1 failed to inhibit the immune response, whereas RNAi targeting Mv-sEH enhanced the immunosuppression. In contrast to the acute (< 12 h pi) immune response involving eicosanoid biosynthesis, the expression of these two genes linked to EpOME metabolism increased significantly at the late infection stage (> 12 h pi). Several alkoxide analogs of EpOME, with the epoxide group replaced by an alkoxide group, were synthesized; one such derivative demonstrated substantially greater efficacy than the natural EpOMEs in inhibiting the immune response. Additionally, using EpOME alkoxide significantly increased the effectiveness of microbial insecticides. Moreover, exposing young larvae to sublethal doses of EpOME alkoxide or sEH inhibitor induced severe developmental delays. These results suggest a novel strategy for insect pest control using insect immune resolvin analogs.

Elicitor-mediated induction of Cajanus cajan defences altered nutritional indices of Maruca Vitrata (Fab.) (Lepidoptera: Crambidae)

Elicitor-mediated induction of Cajanus cajan defences altered nutritional indices of Maruca Vitrata (Fab.) (Lepidoptera: Crambidae)

A chromosome-level genome assembly of the legume pod borer, Maruca vitrata Fabricius (Lepidoptera: Crambidae)

Maruca vitrata, a significant pest of legumes, impacts food security in Asia and Africa. This study presents a high-quality genome assembly of M. vitrata, utilizing advanced sequencing technologies including Nanopore long-read, MGI short-read, and Hi-C. The genome, totaling 482.3 Mb with a contig N50 of 2.91 Mb, features 41.58% repetitive sequences and encompasses 13,320 protein-coding genes. We performed comparative genomic analyses to affirm the accuracy and completeness of the protein sequences assembled, ensuring the assembly’s integrity. Additionally, the annotation of 83 Cytochrome P450 (CYP) genes further confirms the comprehensive nature of the genome assembly and its annotations. This genome assembly not only deepens our understanding of M. vitrata biology but also supports the development of sustainable pest management strategies. This research highlights the importance of genomics in advancing sustainable agricultural solutions through innovative pest management approaches.

A Comparative Analysis of Different Xenorhabdus Strains Reveals a Virulent Factor, Cyclic Pro-Phe, Using a Differential Expression Profile Analysis of Non-Ribosomal Peptide Synthetases.

Entomopathogenic bacteria, classified into the genus Xenorhabdus, exhibit a dual lifestyle as mutualistic symbionts to Steinernema nematodes and as pathogens to a broad range of insects. Bacterial virulence depends on toxin proteins that induce toxemia and various immunosuppressive secondary metabolites that cause septicemia. Particularly, the immunosuppressive properties of Xenorhabdus bacteria determine the variability of their insecticidal activities. This study explored the role of peptide metabolites in virulence and its variation among six bacterial strains across three species: X. nematophila, X. bovienii, and X. hominickii. Initially, their virulence significantly varied against a susceptible lepidopteran host, Maruca vitrata, but showed less variation against a tolerant coleopteran host, Tenebrio molitor, with high median lethal bacterial doses. In M. vitrata, virulence was strongly correlated with bacterial growth rate and inhibitory activity against phospholipase A2. Secondly, the six strains differed in the compositions of their secreted secondary metabolites, analyzed by GC-MS following ethyl acetate extraction. Notably, there was significant variation in the production of di- or tetra-peptides. Highly virulent strains commonly produced the cyclic Pro-Phe (cPF). Thirdly, the expression of non-ribosomal peptide synthetase (NRPS) genes varied greatly among the strains. NRPS genes were minimally expressed in the tolerant T. molitor and highly expressed in the susceptible M. vitrata. In M. vitrata, specific NRPS genes were markedly expressed in the virulent strains. Finally, cPF demonstrated potent immunosuppressive activity against the cellular and humoral responses of M. vitrata. The addition of cPF significantly enhanced the virulence against the tolerant T. molitor. These findings suggest that immunosuppression is necessary for the pathogenicity of Xenorhabdus bacteria, wherein NRPS products play a critical role in suppressing immune-associated factors in target insects.

Seasonal Incidence of Insect Pests on Blackgram [Vigna mungo (L.) Hepper] in Malwa Region of Madhya Pradesh, India

The study investigated the prevalence of major insect pests and their natural enemies in Blackgram crops, focusing on leaf hoppers, whiteflies, Bihar hairy caterpillars, spotted pod borers, stem flies, coccinellids and spiders. Throughout the crop period, the population dynamics of these pests were monitored, revealing varying levels of infestation. The high population of 5.60 leafhoppers per plant and 3.50 larvae per plant of Bihar hairy caterpillar were recorded during 35th week of the crop cycle. The high population of 6.90 whiteflies per plant, 2.60 spotted pod borer larvae per plant and 60 per cent of pod fly infestation were observed during 36th, 37th and 38th week of the crop cycle, respectively. The highest populations of coccinellids 2.40 beetles per plant in 35th week and 2.00 spiders per plant in 36th week recorded duringthe crop cycle. The maximum temperature and relative humidity showed significant positive correlation and minimum temperature and rainfall showed negative non-significant correlation with the population of leaf hopper, Bihar hairy caterpillar, whitefly, stem fly, spotted pod borer and coccinellids. Relative humidity showed positive significant correlation and maximum temperature, minimum temperature and rainfall showed negative non-significant correlation with population of spider.

Association of weather parameters with the incidence of spotted pod borer, Maruca testulalis Geyer infesting green gram

Association of weather parameters with the incidence of spotted pod borer, Maruca testulalis Geyer infesting green gram

Monitoring Insect Pest Complex on Black Gram

The pest spectra, comprising of thirteen species, were observed to attack black gram at different stages of crop growth. The stem fly Ophiomyia phaseoli (Tryon), whitefly, Bemisia tabaci (Gennadius), black aphid Aphis craccivora (Koch), pod bug Riptortus pedestris (F), surface grasshopper, Chrotogonus trachypterous (Blanchard), semilooper, Plusia orichalcea (F), tobacco caterpillar, Spodoptera litura (F), blue butterfly Lampides boeticus (L) and blister beetle Mylabris pustulata (Thunberg) have assumed the status of minor pests whereas, gram pod borer Helicoverpa armigera (Hubner), spotted pod borer Maruca vitrata (Geyer), Bihar hairy caterpillar Spilosoma obliqua (Walker) and leafhopper Empoasca kerri (Pruthi) were recorded as major pests.

Bio Efficacy of Bio Pesticides against Spotted Pod Borer (Maruca vitrata Geyer) Infesting Black Gram

The study entitled “Bio-efficacy of bio-pesticides against spotted pod borer (Maruca vitrata Geyer) infesting black gram” at Organic Research Farm, Karguan Ji, Department of Entomology, Institute of Agricultural Sciences Bundelkhand University, Jhansi (U.P.) during kharif 2023 containing nine treatments viz, Neem oil 5%, Garlic bulb extract 5%, Bacillus thuringiensis 2.50 ml/l, Verticillium lecanii 5 ml/l, Panchagavya 10%, NSKE 5%, Castor oil 5%, Beauveria bassiana 5 ml/l and untreated control in RBD with three replications aiming to evaluate their efficacy of bio-pesticides against spotted pod borer. To evaluate the efficacy, two applications of treatments were carried out, and the spotted pod borer infestation on selected plants were evaluated after three, seven, and fourteen days after spraying. The outcomes showed that In the management of the spotted pod borer after the first and second spray, the Beauveria bassiana 5 ml/l (2.14) was superior and best effective in controlling larval population, followed by Bacillus thuringiensis 2.50 ml/l (2.34), and neem oil 5% (2.59), and the maximum yield 13.85 qt/ha and C: B ratio 1:1.71 was obtained from the Beauveria bassiana treated plot followed by Bacillus thuringiensis and neem oil by that obtained 12.89 qt/ha and 12.55 qt/ha yield, moreover 1:1.64 and 1:1.52 C: B ratio respectively.

Insights in to the successful semi-synthetic diets for invitro mass rearing of spotted pod borer, Maruca vitrata (Crambidae: Lepidoptera)

Insights in to the successful semi-synthetic diets for invitro mass rearing of spotted pod borer, Maruca vitrata (Crambidae: Lepidoptera)

Effects of the area of source habitat and habitat connectivity on soybean pod borer damage: Implications for area-wide management

The soybean pod borer, Leguminivora glycinivorella (Matsumura), is an important soybean pest that reduces both quality and yield in Asia, and chemical control is used irrespective of the damage risk. The pest population density increases at continuously cropped soybean fields (hereafter, source habitat). The present study would contribute to proposing pest management options matched to the damage risk by clarifying the surrounding landscape structures where damage is likely to increase. First, we clarified the relationship between the probability of grain damage and the source habitat within a 350 m radius of the new or continuously cropped soybean fields. The habitat area surrounding continuous soybean fields positively influenced the probability of grain damage but did not detect a significant effect in new soybean fields. Secondly, we clarified the relationship between the probability of grain damage and habitat connectivity in continuous soybean fields. Well-managed fields with high connectivity consistently showed low damage risk. Meanwhile, damage risk varied in fields with low connectivity, indicating that damage is unlikely to occur because soybean pod borers are difficult to invade. However, once invaded, the damage could be extensive. Considering these results, one possible new control system will allow the spatiotemporal variation in the number of insecticide applications. The present study likely contributes to understanding the relationship between soybean pod borer injury and landscape structure, which is important for area-wide pest management.

Predicting habitat suitability for the soybean pod borer Leguminivora glycinivorella (Matsumura) using optimized MaxEnt models with multiple variables.

The soybean pod borer Leguminivora glycinivorella (Matsumura) is one of the most important soybean pests and often causes serious damage to Glycine max (L.) Merr., a leading source of dietary protein and oil in animal feed. However, the potential distribution patterns of this economically important pest and its driving factors require further investigation. Here, we used the optimized MaxEnt model to predict the potential distribution of this pest with multiple variables associated with climate, land use, and host plant, at its recorded range and a globe scale. Based on 4 variable combinations, the results show that the current suitable habitats of L. glycinivorella are primarily distributed in most of China, the Korean Peninsula, and Japan. Whereas no suitable area is present in other continents. In future projections, the suitable region shows a slight northward expansion compared with the result predicted with current climatic conditions, and the suitable areas of almost all future projections were stable in size. Among the 9 bioclimatic factors, BIO03 (isothermality) consistently highly contributes to the predictions, indicating that temperature may be a key factor influencing the habitat distribution of L. glycinivorella. Comparative analyses of projections further show that non-climatic factors are informative in the modeling as routinely used bioclimate variables. The spatio-temporal distribution patterns of suitable habitats and the regulatory factors predicted in this study could provide important guidance for L. glycinivorella management.

Morphological Basis of Resistance in Pigeonpea (Cajanus cajan (L.) Millsp.) against Pod Borer Complex

Field experiment was carried out to determine the morphological basis of resistance in pigeonpea against pod borer complex during kharif 2021-22, 2022-23 and 2023-24 at College of Agriculture, Navsari Agricultural University, Bharuch (Gujarat). Among the twelve pigeonpea genotypes/cultivars screened, BP-17-02 was found highly resistant and BP-16-182, BP-16-228, BP-16-261, ICPL-87119 and BP-16-166 were found resistant whereas, GNP-2 and Vaishali were found highly susceptible against pod borers. Genotypes/cultivars namely, BP-16-178, ICPL 87119, BP-16-182, BP-16-228 and BP-16-183 were found resistant to pod fly. Genotypes/cultivars having short pod length, narrow pod breadth, narrow seed breadth, more seeds/pod, more seed weight, more seed density, thick pod wall thickness and long trichome length recorded lower pod borers population. Pod length had a significant positive correlation with Maruca vitrata, Exelastis atomosa and Melanagromyza obtusa. Significant positive association was found between pod breadth and larval population of Helicoverpa armigera and Maruca vitrata. Significant negative correlation was found between Exelastis atomosa and pod wall thickness.

Seasonal Incidence of Spotted Pod Borer (Maruca vitrata F.) in Indian bean and Correlation with Meteorological Aspects

Aim: To study the population dynamics of spotted pod borer infesting Indian bean in relation to weather parameters Study Design: Field trail; Randomized Block Design. Place and Duration of Study: The study was conducted at College farm at Navsari Agricultural University during Rabi of 2022-23 and 2023-24. Methodology: 50 plants were randomly selected from the net plot area. The observations on the number of larvae per plant and per cent pod damage were counted. Results: The larval population, in year 2022-23 started from 51st SMW. The peak activity was observed in 4th SMW when 6.46 larvae/plant population was recorded which coincided with the peak flowering stage. During the second season (year 2023-24) also, the pest population started from 51st SMW with pest population of 0.8 larvae/plant. The peak pest population was observed on 4th SMW with 6.84 larvae/plant. The pod damage started from 2nd SMW with 10.05 per cent and gradually increased. The peak was recorded in 12th SMW, highest pod damage was observed with 55.89 per cent. Similar to previous year, the pod damage was recorded from 2nd SMW with 11.67 per cent and peak was seen in 8th SMW with 56.63 per cent damage. The correlation of number of larvae per plant with maximum (r=-0.63), minimum (r=-0.62), average temperature (r=-0.74) and average vapour pressure (r=-0.59) showed significantly negative correlation. During year 2023-24, minimum (r=-0.637) and average temperature (r=-0.610) showed significant negative correlation. In case of pod damage, it was revealed that maximum temperature (r=0.58) and bright sunshine hours (BSSH) (r=0.59) exhibited significant positive correlation with pod damage per cent, in year 2022-23. A similar trend was seen in year 2023-24 where, maximum temperature (r=0.692) and BSSH (r=0.787) showed significant positive correlation. Conclusion: Temperature and to some extent vapour pressure plays a significant role in the population fluctuation of spotted pod borer in Indian bean.

Comparative efficacy of selected biopesticides against spotted pod borer [Maruca vitrata (Fab.)] infesting cowpea (Vigna unguiculata L.) in Prayagraj (U.P.)

Comparative efficacy of selected biopesticides against spotted pod borer [Maruca vitrata (Fab.)] infesting cowpea (Vigna unguiculata L.) in Prayagraj (U.P.)

Biophysical and biochemical bases of resistance to Maruca vitrata L. in selected vegetable cowpea genotypes

Host plant resistance is a crucial factor in mitigating the damages caused by Maruca vitrata, the most devastating pest of vegetable cowpea, commonly known as the legume pod borer. Understanding the biophysical and biochemical aspects of resistance is essential for developing methods to breed insect pest resistance in germplasm. To identify genotypes with diverse traits associated with resistance to this pest, we investigated the biophysical and biochemical traits implicated in conferring resistance to M. vitrata across ten accessions of vegetable cowpea, alongside resistant and susceptible check. Trichomes on pods emerged as a pivotal aspects of resistance in these genotypes, exhibiting a significant negative correlation with the percentage of seed damage inflicted by M. vitrata. In our study, genotypes with higher pod trichome density showed a reduction in seed damage caused by the pest. Additionally, a high phenol concentration and low levels of total sugars and proteins were associated with resistance to M. vitrata. Vegetable cowpea genotypes characterized by abundant pod trichomes and elevated phenol level hold promise for breeding efforts aimed at developing cultivars resistant to M. vitrata.

Assessment of yield losses due to Maruca vitrata (Fabricius) in kharif mungbean in Punjab

Assessment of yield losses due to Maruca vitrata (Fabricius) in kharif mungbean in Punjab

Assessing the Impact of Weather Variables on Maruca vitrata (F) Population Dynamics in Green Gram and Evaluating the Efficacy of Various Insecticides

Assessing the Impact of Weather Variables on Maruca vitrata (F) Population Dynamics in Green Gram and Evaluating the Efficacy of Various Insecticides

Comparative Studies of Lepidopteran Pest Incidence on JL 24 and DH 256 Varieties of Groundnut

This experiment compares the incidence of lepidopteran pests under protected and unprotected groundnut cultivation at AICRP on Groundnut, MARS, Dharwad, Karnataka in the kharif season of 2021–2022. In order to protect the protected plot from pests, protection measures were implemented at 50 DAS using flubendiamide 20 WG @ 0.5g/l for leaf-eating caterpillars. Based on the crop's phenology, observations were made. Spodoptera litura, Thysanoplusia orichalcea, Helicoverpa armigera, and Maruca vitrata, were deemed to be the main pests, with the remaining pests being of less significance based on their population density and type of damage. When comparing unprotected JL-24 and DH-256 crop plots to protected plots, the majority of major and minor pests were infested during the vegetative to maturity stage, with maximum infestation occurring during the pod formation and pod filling stages of the crop. In comparison to unprotected plots, protected plots had the highest pod and haulm yields.