Anticarsia Gemmatalis Research Articles (Page 1)

Soybeans are one of the most important crops in Brazil, accounting for an estimated planted area of ​​around 47.61 million hectares in 2024/2025. Among the pests affecting this crop, the velvetbean caterpillar, Anticarsia gemmatalis Hübner, 1818 (Lepidoptera: Erebidae), stands out due to its potential to cause up to 100% defoliation. This study aimed to evaluate the spatial distribution of the velvetbean caterpillar using geostatistical methods. The experiment was conducted with the soybean cultivar M 7908 RR1 during the 2014/2015 growing season in an 8,000 m² area, divided into 80 plots of 100 m² each. In each sampling unit (100 m²), five points were randomly selected, and the number of small, medium, and large caterpillars was counted. The semivariogram models fitted to the data demonstrated that the pest occurs in an aggregated pattern in the field, with a spatial dependence range varying from 7 to 55.42 meters.

Outbreaks of Rachiplusia nu have occurred on soybean in Brazil as the first species resistant to the Bt soybean expressing only Cry1Ac protein, triggering a significant increase in insecticide use on the crop. This threatens one of the most important benefits of adopting Bt soybean cultivars - the reduction of chemicals. Therefore, this research studied the biology and parasitism capacity of Trichogramma pretiosum at 20, 25, and 30 ± 2 °C on R. nu eggs in order to evaluate the potential of releasing this egg parasitoid in soybean to manage R. nu. Parasitoid exhibited high biological performance on the R. nu eggs as observed in the lifetime parasitism of 24.9, 46.4, and 34.4 R. nu eggs at 20, 25, and 30 °C, respectively, and 100% emergence in both biology and parasitism capacity experiments. The sex ratio was statistically lower at 20 °C (0.4947), but at all studied temperatures, the production of female descendants was equal (sex ratio of 0.4947 at 20 °C) or higher (sex ratio of 0.6666 at 25 °C and 0.6524 at 30 °C). All other evaluated parameters were similar to previously positive recorded observations for T. pretiosum on other soybean pests, such as Anticarsia gemmatalis and Chrysodeixis includens, against which the parasitoid has already been commercially released in the fields as a biocontrol option. Therefore, T. pretiosum might also be released in soybean as an egg parasitoid against R. nu, what needs to be confirmed in future field trials.

Objective: This study aimed to assess the parasitism preference of Trichogramma atopovirilia on Anticarsia gemmatalis eggs derived from caterpillars fed on leaves of both resistant and susceptible soybean plants. Theoretical Framework: In an integrated pest management program for soybean cultivation, various control techniques are considered, encompassing chemical control, biological control, and the utilization of resistant plants. Method: Cards containing eggs from the host reared on the two different substrates were presented to Trichogramma atopovirilia in free-choice and confinement systems. Results and Discussion: In the free-choice test, the parasitoid exhibited no discernible preference for eggs from A. gemmatalis reared on resistant or susceptible soybeans. Conversely, in the test where parasitoids were confined to eggs from only one food substrate, parasitism was more pronounced in eggs from A. gemmatalis reared on resistant soybeans. Research Implications: These findings suggest that the parasitoid's association with resistant plants can be effective in controlling soybean caterpillars. Originality/Value: This study contributes to the literature by exploring the parasitism behavior of Trichogramma atopovirilia in relation to the dietary background of Anticarsia gemmatalis, addressing a gap in the interaction between resistant soybean varieties and biological control agents. The relevance of this work lies in its potential to improve integrated pest management strategies by aligning host plant resistance with parasitoid efficacy. These findings support the development of more sustainable approaches to controlling soybean pests while minimizing chemical inputs.

ABSTRACT The São Francisco Submedium Valley in Brazil is the country’s most important table grape exportation region. In 2015, a new pest was reported in the area, the American grapevine moth Lasiothyris luminosa (Razowski & Becker) (Tortricidae), causing significant damage from the bud flowers until the grape berries in the harvesting period. The present work aimed to evaluate artificial diets to guarantee the rearing of L. luminosa in laboratory conditions. Two artificial diets used to rear Anticarsia gemmatalis Hübner and Helicoverpa zea (Boddie) were compared to the species’ natural host (grape berries). It was evaluated the larva, pupal, and larval-pupal period, longevity, fecundity, larval and pupal viability, and sex ratio. L. luminosa completed its cycle in both artificial diets, making it possible to use both to maintain the species in the laboratory. The larval and larval-adult period were shorter for the treatment with A. gemmatalis artificial diet. Also, this diet provided greater pupal viability and higher fecundity. Thus, the A. gemmatalis diet is more indicated to rear L. luminosa in the laboratory than the H. zea diet and grape berries.

The velvetbean caterpillar Anticarsia gemmatalis is one of the main soybean defoliators in Brazil. Currently, the main biopesticide used to control insect pests worldwide is the bacteria Bacillus thuringiensis (Bt), which produces entomopathogenic Crystal toxins (Cry) that act in the midgut of susceptible insects, leading them to death. The mode of action of Cry toxins in the midgut involves binding to specific receptors present on the brush border of epithelial cells such as aminopeptidase N (APN), alkaline phosphatase (ALP), cadherin, and others. Mutations in these receptors, among other factors, may be involved in the development of resistance; identification of functional Cry receptors in the midgut of A. gemmatalis is crucial to develop effective strategies to overcome this possible scenario. This study's goal is to characterize APNs of A. gemmatalis and identify a receptor for Cry1Ac in the midgut. The interaction of Bt spores with the midgut epithelium was observed in situ by immunohistochemistry and total aminopeptidase activity was estimated in brush border membrane vesicle (BBMV) samples, presenting higher activity in challenged individuals than in control ones. Ten APN sequences were found in a A. gemmatalis' transcriptome and subjected to different in silico analysis, such as phylogenetic tree, multiple sequence alignment and identification of signal peptide, activity domains and GPI-anchor signal. BBMV proteins from 5th instar larvae were submitted to a ligand blotting using activated Cry1Ac toxin and a commercial anti-Cry polyclonal antibody; corresponding bands of proteins that showed binding to Cry toxin were excised from the SDS-PAGE gel and subjected to mass spectrometry analysis, which resulted in the identification of seven of those APNs. Quantitative PCR was realized to compare expression levels between individuals subjected to sublethal infection with Bt spores and control ones, presenting up- and downregulations upon Bt infection. From these results, we can infer that aminopeptidases N in A. gemmatalis could be involved in the mode of action of Cry toxins in its larval stage.

The egg parasitoid Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogrammatidae) is a biological control agent for the soybean (Glycine max (L.) Merril)) caterpillar Anticarsia gemmatalis Hübner (Lepidoptera: Erebidae). An appropriate proportion of eggs and the embryonic age of the host are important features for achieving good parasitism rates by these natural enemies. Thus, the objective of the present study was to analyze some biological aspects of T. atopovirilia with A. gemmatalis eggs at different densities and embryonic ages. The density and embryonic age of the A. gemmatalis eggs affected the sex ratio and the number of parasitized eggs per female, individuals per egg, and females of T. atopovirilia that emerged per treatment. However, these factors did not affect the emergence percentage. The development of T. atopovirilia was optimal with 20 and 25 A. gemmatalis eggs within 24 and 48 h of embryonic development, per female of this parasitoid.

Environmental variability can significantly impact individual survival and reproduction. Meanwhile, high population densities can lead to resource scarcity and increased exposure to parasites and pathogens. Studies with insects can offer valuable insights into eco-immunology, allowing us to explore the connections between these variables. Here we use the moth Anticarsia gemmatalis to examine how increases in population density and immunological challenge during the larval stage shape its investment in immune defence and reproduction. Larvae reared at a high population density exhibited greater lytic activity against bacteria compared to those reared at low density, whilst bacterial challenge (i.e. bacteria-immersed needles) also increased lytic activity. There was no interaction between the variables population density and bacterial challenge, indicating that these are independent. Surprisingly, neither increase in lytic activity carried through to activity in prepupal haemolymph. Rearing of larvae at a high density delayed pupation and decreased pupal weight. The immunological stimulus did not significantly influence pupal development. Lower population density as a larva resulted in greater adult weight, but did not significantly influence lytic activity in the eggs or the number of eggs laid. Negative correlations were found between lytic activity in the eggs and the number of eggs, as well as between adult weight and the number of eggs. Overall, this study demonstrates that high population density and immune challenge trigger increased lytic activity in caterpillars, but this effect is transient, not persisting into later stages. The trade-offs observed, such as delayed pupation and reduced prepupal weights under high density, suggest a balancing act between immune investment and developmental aspects. The findings hint at a short-term adaptive response rather than a sustained strategy. The implications of delayed pupation and smaller adult moths could influence the moth's life history strategy, impacting its role in the ecosystem. Further research tracking larval immune investment and subsequent reproductive success will unveil the evolutionary dynamics of this relationship in changing environments.

The soybean caterpillar, Anticarsia gemmatalis Hubner (Lepidoptera: Noctuidae), damages this plant. This pest is controlled, mainly, with chemical products which makes it necessary to to develop management strategies for its management in the soybean crop. Feeding and development of A. gemmatalis larvae fed on soybean leaves treated with Bacillus thuringiensis Berliner var. kurstaki at different concentrations (0,5, 1, 2, 4, 6, 8 μg.mL-1 ) for 24 h were studied in the laboratory. The LC50 and LC90 after 24 h from hatching and at the last instar, development period, adult emergence, weight gain by larva, pupa weight, and dry food weight ingested besides of A. gemmatalis were evaluated. The LC90 value decrease with the development of this insect. Mortality in the third instar of this pest was proportional to the B. thuringiensis concentrations. Emergence of A. gemmatalis adults was higher with 0,5 μg.mL-1 concentration of this bacterium and in the control.

Baccharis essential oils from the Atlantic Forest as sources of natural pesticides

Exposure to insecticides cause mortality, respiratory disturbs, and antifeeding effects in Anticarsia gemmatalis

Gene expression, proteomic, and metabolic profiles of Brazilian soybean genotypes reveal a possible mechanism of resistance to the velvet bean caterpillar Anticarsia gemmatalis

ABSTRACT: Anticarsia gemmatalis (Lepidoptera: Erebidae) is distributed in tropical and subtropical regions of America, and is an important pest of Fabaceae, such as: soybean, peanut, common bean, cowpea, pea, chickpea and kudzu. In soybean, the velvet bean caterpillar is important due to the plant defoliation in their larval stage. This study evaluated soybean cultivars as source of resistance to A. gemmatalis by antixenosis (attractiveness and non-preference for feeding) and antibiosis (biological parameters of the insect). The parameters evaluated were: antixenosis: attractiveness and non-preference, dry mass consumed and attractiveness index and antibiosis: duration of larval and pupal stages, adult longevity, total cycle, larval and pupal weights and larval, pupal and total viability. Considering antixenosis and antibiosis the least suitable cultivars for A. gemmatalis were found to be BRS 8383 IPRO, BRS 1074 IPRO, BRS 1061 IPRO, BRS 7180 IPRO, BRS 9383 IPRO, BRS 8980 IPRO and BRS 1003 IPRO due to high mortality in the larval phase. The cultivars BRS 523 and BRS 543 RR “block technology” suggest displays antixenosis and or antibiosis to A. gemmatalis. These cultivars can be used by soybean producers in combination with other control tactics in soybean IPM.

Anticarsia gemmatalis Hünber, 1818 is one of the main defoliating species in the soybean crop. Bacillus thuringiensis Berliner, 1915, is a bacterium used in the biological control of this pest species. Resistant populations and their sublethal effects caused by the use of the bacteria have already been reported; however, there are no studies on phenotypic plasticity in adulthood exposed to Bt-based bioinsecticide sub-doses. This study aimed to evaluate the morphometry of A. gemmatalis adults under laboratory conditions submitted to the Bt-based bioinsecticide Dipel® over the three generations. The body segments mensuread were width, length, and area of the anterior and posterior wings, the weight of the integument, chest, abdomen, wings, and the whole adult of males and females. Among the treatments, LC5 in the first generation and LC10 in the second generation were those with lower thresholds in relation to the weight of the chest and abdomen, considering the proportions of the body smaller than the females. The female's weight adulthood was reduced by 10% about males, and, only in the first generation. Males have larger body size and more pronounced phenotypic plasticity than females. Here, we demonstrate the first study assessing the phenotypic plasticity of A. gemmatalis adults.

Outbreaks of Anticarsia gemmatalis (Hübner, 1818) (Lepidoptera: Erebidae), a major pest of soybean, can be controlled below economic thresholds with methods that do not involve the application of synthetic insecticides. Formulations based on natural isolates of the Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) (Baculoviridae: Alphabaculovirus) played a significant role in integrated pest management programs in the early 2000s, but a new generation of chemical insecticides and transgenic soybean have displaced AgMNPV-based products over the past decade. However, the marked genotypic variability present among and within alphabaculovirus isolates suggests that highly insecticidal genotypic variants can be isolated and used to reduce virus production costs or overcome isolate-dependent host resistance. This study aimed to select novel variants of AgMNPV with suitable insecticidal traits that could complement the existing AgMNPV active ingredients. Three distinct AgMNPV isolates were compared using their restriction endonuclease profile and in terms of their occlusion body (OB) pathogenicity. One isolate was selected (AgABB51) from which eighteen genotypic variants were plaque purified and characterized in terms of their insecticidal properties. The five most pathogenic variants varied in OB pathogenicity, although none of them was faster-killing or had higher OB production characteristics than the wild-type isolate. We conclude that the AgABB51 wild-type isolates appear to be genotypically structured for fast speed of kill and high OB production, both of which would favor horizontal transmission. Interactions among the component variants are likely to influence this insecticidal phenotype.

Abstract The velvetbean caterpillar Anticarsia gemmatalis (VBC) is widely distributed in the Americas and causes severe damage to soybean foliage. This insect presents high ecological plasticity, a feature that is of great importance to understand its genetic diversity and potential gene flow to assist in resistance management strategies. With this objective, we developed microsatellite markers for VBC and applied them to five populations from Brazil. Nine primers were polymorphic, with high values of polymorphic information content (PIC > 0.5), and 134 alleles were identified in 155 individuals. These primers indicated deviation from the Hardy–Weinberg equilibrium for all populations (observed heterozygosity, Ho = 0.48, expected heterozygosity, He = 0.76), with moderate to high levels of genetic diversity and a moderate fixation index (FST = 0.14) among the populations. Analysis of population structure indicated the formation of two principal clusters. The northern one can be divided into the two populations that formed the cluster, with high genetic differentiation between them. The other cluster is formed by three populations, and we found evidence of low gene flow between them in the south–north direction, indicating that these populations may be migratory in certain conditions. These findings indicate that the designed primers were effective in describing the genetic diversity of VBC, with major implications for integrated pest management. Given the little gene flow and the high genetic diversity of populations, they present great potential to become resistant to control practices, which can lead to increased management costs.

Abamectin induces mortality, inhibits food consumption, and causes histological changes in the midgut of the velvetbean caterpillar Anticarsia gemmatalis (Lepidoptera: Noctuidae)

Transposable elements (TEs) are DNA sequences that possess the ability to move from one genomic location to another. These sequences contribute to a significant fraction of the genomes of most eukaryotes and can impact their architecture and regulation. In this paper, we present the first data related to the identification and characterization of TEs present in the transcriptome of Anticarsia gemmatalis. Approximately, 835 transcripts showed significant similarity to TEs and (or) characteristic domains. Retrotransposons accounted for 71.2% (595 sequences) of the identified elements, while DNA transposons were less abundant, with 240 annotations (28.8%). TEs were classified into 30 superfamilies, with SINE3/5S and Gypsy being the most abundant. Based on the sequences of TEs found in the transcriptome, we were able to locate conserved regions in the chromosomes of this species. The analysis of differential expression of TEs in susceptible and resistant strains, challenged and not challenged with Bacillus thuringiensis (Bt) from in silico analysis, indicated that exposure to Bt can regulate the transcription of mobile genetic elements in the velvetbean caterpillar. Thus, these data contribute significantly to the knowledge of the structure and composition of these elements in the genome of this species, and suggest the role of stress on their expression.

Bacillus thuringiensis (Bt) is a biological alternative to the indiscriminate use of chemical insecticides in agriculture. Due to resistance development on insect pests to Bt crops, isolating novel Bt strains is a strategy for screening new pesticidal proteins or strains containing toxin profile variety that can delay resistance. Besides, the combined genomic and proteomic approaches allow identifying pesticidal proteins and virulence factors accurately. Here, the genome of a novel Bt strain (Bt TOL651) was sequenced, and the proteins from the spore-crystal mixture were identified by proteomic analysis. Toxicity bioassays with the spore-crystal mixture against larvae of Diatraea saccharalis and Anticarsia gemmatalis, key pests of sugarcane and soybean, respectively, were performed. The toxicity of Bt TOL651 varies with the insect; A. gemmatalis (LC50 = 1.45ngcm-2) is more susceptible than D. saccharalis (LC50 = 73.77ngcm-2). Phylogenetic analysis of the gyrB gene indicates that TOL651 is related to Bt kenyae strains. The genomic analysis revealed the presence of cry1Aa18, cry1Ac5, cry1Ia44, and cry2Aa9 pesticidal genes. Virulence factor genes such as phospholipases (plcA, piplc), metalloproteases (inhA), hemolysins (cytK, hlyIII, hblA, hblC, hblD), and enterotoxins (nheA, nheB, nheC) were also identified. The combined use of the genomic and proteomic data indicated the expression of Cry1Aa18, Cry1Ac5, and Cry2Aa9 proteins, with Cry1Ac5 being the most abundant. InhA1 also was expressed and may contribute to Bt TOL651 pathogenicity. These results provide Bt TOL651 as a new tool for the biocontrol of lepidopteran pests.

The present work aimed to evaluate the insecticidal activity of Cymbopogon citratus essential oil and its major compounds (citral and myrcene) on Anticarsia gemmatalis. The essential oil, citral, myrcene, and a mixture of citral and myrcene were tested at the concentrations of 0.1, 0.3, 0.5, 0.7, and 0.9 % v/v, plus two negative controls (distilled water and Tween-80® 0.5 % v/v) and a positive control (novaluron 0.075 % w/v). Insect mortality was evaluated in 24, 48, 72, and 96 h. According to the results, C. citratus essential oil and the citral-myrcene mixture at 0.9 % v/v were effective in the control of A. gemmatalis, with 96 % and 88 % mortality, respectively, in the first 24 h. At this concentration, citral caused 100 % mortality after 72 h, whereas myrcene had no effect on the caterpillars even after 96 h of exposure. Thus, C. citratus essential oil can be a potential option for the alternative control of A. gemmatalis.

Brazil is the largest producer of soybeans in the world. The vast extent of soybean plantations across the Brazilian territory exposes this crop to attack by several insects, including the velvetbean caterpillar, Anticarsia gemmatalis. One of the alternatives used to control this insect are the toxins produced by Bacillus thuringiensis (Bt). However, in some cases, resistance to these toxins has been reported in the laboratory. Despite the ecological and economic impact of the velvetbean caterpillar, there are few studies on the genetic structure of this species, especially with regard to microsatellites. In this paper, we carried out a comparative transcriptional analysis of microsatellites in resistant (RES) and susceptible (SUS) strains of A. gemmatalis challenged and not challenged with Bt toxins. According to the number of sequences analyzed in each group, a 7.9% simple sequence repeat (SSR) rate was identified for the SUS library, and 7.4% for SUSBt. For the RES group, this value was 8.5% and for the RESBt 7.7%. Most of the fragments found showed a shorter repeat pattern, located in mono- and trinucleotide motifs. Among the 128 types of SSR motifs, it was possible to notice a large amount of adenine and thymine in relation to guanine and cytosine, which was also seen in chromosomes after staining with base-specific fluorochromes DAPI/CMA₃, highlighting DAPI-positive regions. Although the participation of microsatellites in the resistance mechanism of A. gemmatalis to Bt is not clear, the results obtained in this work contribute to a better understanding of the repetitive DNA found in transcribed regions of a non-model organism.