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To effectively combat the re-infestation of boll weevils (Anthonomus grandis L.) in cotton fields, it is necessary to address the detection of volunteer cotton (VC) plants (Gossypium hirsutum L.) in rotation crops such as corn (Zea mays L.) and sorghum (Sorghum bicolor L.). The current practice involves manual field scouting at the field edges, which often leads to the oversight of VC plants growing in the middle of fields alongside corn and sorghum. As these VC plants reach the pinhead squaring stage (5–6 leaves), they can become hosts for boll weevil pests. Consequently, it becomes crucial to detect, locate, and accurately spot-spray these plants with appropriate chemicals. This paper focuses on the application of YOLOv5m to detect and locate VC plants during the tasseling (VT) growth stage of cornfields. Our results demonstrate that VC plants can be detected with a mean average precision (mAP) of 79% at an Intersection over Union (IoU) of 50% and a classification accuracy of 78% on images sized 1207 × 923 pixels. The average detection inference speed is 47 frames per second (FPS) on the NVIDIA Tesla P100 GPU-16 GB and 0.4 FPS on the NVIDIA Jetson TX2 GPU, which underscores the relevance and impact of detection speed on the feasibility of real-time applications. Additionally, we show the application of a customized unmanned aircraft system (UAS) for spot-spray applications through simulation based on the developed computer vision (CV) algorithm. This UAS-based approach enables the near-real-time detection and mitigation of VC plants in corn fields, with near-real-time defined as approximately 0.02 s per frame on the NVIDIA Tesla P100 GPU and 2.5 s per frame on the NVIDIA Jetson TX2 GPU, thereby offering an efficient management solution for controlling boll weevil pests. [ABSTRACT FROM AUTHOR]

Background: Anthonomus grandis grandis is the main cotton pest in the Americas, with the potential to become a pest in other continents. The insect uses the plant's reproductive organs for feeding, oviposition, and survival strategies in the off-season, sheltering in dry bolls. This study aimed to know the reproductive potential, feeding, longevity, and morphometric characteristics of boll weevils from dry bolls, squares, and traps. Adults were obtained from infested squares, dry bolls, and traps installed in cotton fields and the Caatinga area. Thirty weevil pairs were maintained in the laboratory to assess the oviposition, feeding holes, longevity, and morphometric measurements of the parental and F1 generations. Results: In the parental generation, boll weevils from traps (the Caatinga area and cotton cultivation) showed greater reproductive potential. Boll weevils from squares and the Caatinga area showed greater feeding activity compared with those from cotton cultivation. Greater rostrum length, thorax + abdomen length, and abdomen width were observed in boll weevils from cotton cultivation and dry bolls. The origin of boll weevils parental generation did not affect progeny emergence time. The F1 generation of boll weevils showed significant differences in average longevity depending on the origin of different microhabitats. Furthermore, differences in rostrum lengths were observed, with the boll weevils coming from traps installed in cotton cultivation, the Caatinga area, and dry bolls being the largest. Regarding thorax + abdomen length and abdomen width, the highest values were observed in those from the Caatinga area and cotton cultivation. Conclusion: It was proven that dry bolls did not affect the reproductive, feeding, and longevity performance of boll weevils, enabling better insect fitness (reproduction and size) in relation to those coming from squares. The use of dry bolls as off-season shelter is an important survival strategy for the boll weevil. [ABSTRACT FROM AUTHOR]

Herbivorous arthropods can induce their host to form structures where they shelter during unfavourable periods. The boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), can spend the off‐season inside cotton plant structures, known as dry bolls, protected from pesticides, natural enemies and heat and desiccation on the soil surface, thereby increasing its survival and preserving its reproductive capacity. However, the relationship between the boll weevil and dry boll formation is not fully understood and requires further study. The formation and external and internal characteristics of dry bolls on cotton plants infested with different densities of boll weevils, and the emergence and survival of this insect from these structures, were evaluated. Compared with non‐infested control plants, plants infested with boll weevil formed almost twice as many dry bolls, which were 2.3 times heavier and with a diameter 1.7 times larger than those on non‐infested plants. Boll weevil infestation reduces the number of bolls and commercial mass of fibre + seeds, reducing productivity and increasing cotton harvest contaminants. However, dry bolls on non‐infested plants demonstrate that other factors are involved in their formation. [ABSTRACT FROM AUTHOR]

Cotton, Gossypium hirsutum L., has an indeterminate growth habit. Therefore, the plant growing season leads to crops with a large amount of immature vegetative and reproductive structures, thus requiring the use of defoliants to promote the abscission of these structures and enable mechanical harvesting. However, the use of defoliants can negatively affect the development of immature fruits.This study examined the influence of defoliants, applied alone or in combination with each other, on the formation of dry and malformed reproductive structures of cotton, known as dry bolls, used as shelter by the boll weevil Anthonomus grandis grandis Boheman during cotton fallow periods. We investigated the influence of defoliants, applied alone, or combined with each other or with insecticide, on boll weevil mortality. In addition, we tested the susceptibility of boll weevils inside dry bolls to the action of insecticide.The results indicate that the defoliants can increase the number of dry bolls by up to 3.4 times, in relation to the control, 20 days after its application. The studied defoliants did not exert toxic effects on boll weevil when applied separately, nor synergistic effects of toxicity when combined with each other or with insecticides. At the end of the insecticide spraying experiments, the number of live boll weevils was 8.4 times greater when the insect was housed in dry capsules than when not housed.Defoliants can increase the formation of dry bolls, which can reduce boll weevil mortality due to insecticide application and hamper pest management. [ABSTRACT FROM AUTHOR]

Anthonomus grandis Boheman (Coleoptera: Curculionidae) is comprised of two subspecies: the boll weevil (A. g. grandis) and the thurberia weevil (A. g. thurberiae). The thurberia weevil is generally regarded as a non-pest variant of the species, whereas the boll weevil is an important economic pest of commercial cotton. In the USA, a nationwide eradication program has been largely successful against the boll weevil, but reintroductions of eradicated zones remain a threat. In 2015, A. grandis was trapped in the functionally eradicated Winter Garden growing region in Texas, where it had not been found since 2012. Weevils established in the area and triggered a multi-year, multi-million-dollar mitigation effort. In 2017, the species was trapped in Hidalgo County, New Mexico, another area where it had been previously eradicated. In this study, we obtained specimens from both trapping events and used double digest restriction site-associated DNA sequencing to obtain genetic data in homology with previously published A. grandis population genetic data. We conducted source tracing to match the captured weevils to previously described populations to determine a likely source population. We also compared the accuracy of the approach to other diagnostic methods currently used by the United States Department of Agriculture. The results suggested that a small founder population of weevils dispersed from the Lower Rio Grande Valley population in southern Texas and northern Tamaulipas and established in the Winter Garden. In Hidalgo Co., NM, the weevils were found to be genetically indistinct from non-pest populations of thurberia weevil associated with Arizona wild cotton (Gossypium thurberi). Thurberia weevils in Arizona remain unlikely to threaten commercial growers. Improved rapid diagnostic tools may be desirable to enable better assessment of trap captures and allow for a reduction in the application of mitigation efforts when the non-pest variant is identified. [ABSTRACT FROM AUTHOR]

Background: To control the boll weevil Anthonomus grandis grandis (Coleoptera: Curculionidae), a key pest of cotton in the Americas, insecticides have been intensively used to manage their populations, increasing selection pressure for resistant populations. Thus, this study aimed to detect insecticide resistance and assess insecticide control failure likelihood of boll weevil populations exposed to malathion, profenophos + cypermethrin, and fipronil insecticides. Results: Twelve populations of the boll weevil were collected from commercial cotton fileds of the state of Bahia, northeastern Brazil. These populations were exposed to malathion, profenophos + cypermethrin mixture, and fipronil, at their respective maximum label dose for field applications. Three replicates of 10 adult beetles were exposed to the insecticides and mortality was recorded after 24 h treatment. The control failure likelihood was determined after 48 h. Highest median lethal times (LT50) were observed for malathion and the profenophos + cypermethrin mixture. Resistance to at least one insecticide was detected in 11 populations; three populations were resistant to malathion and profenophos + cypermethrin; seven were resistant to all insecticides tested. The resistance levels were low (< 10-fold) for the three insecticides. Among 12 populations tested, 58% of them exhibited significant risk of control failure for the insecticides malathion and profenophos + cypermethrin. The insecticide fipronil was efficient for the control of the boll weevil in 83% of the populations. Conclusions: The results confirm the significant risk of insecticide control failure in the boll weevil populations to the main compounds used in the region. Thus, proper insecticide resistance management plans are necessary for the boll weevil in the region, particularly for malathion and profenophos + cypermethrin insecticides. [ABSTRACT FROM AUTHOR]

Simple Summary: Rapid diagnostic tools are critical for the management and eradication of boll weevil, Anthonomus grandis grandis. Here, we present the development and validation of a novel qPCR assay that enables same-day identification of Anthonomus grandis subspecies. Rapid and accurate identification of Anthonomus grandis subspecies is crucial for effective management and eradication. Current diagnostic methods have limitations in terms of time to diagnosis (up to seven days) and can yield ambiguous results. Here, we present the validation of a custom TaqMan SNP Genotyping Assay for the rapid and accurate identification of A. grandis grandis (boll weevil) and A. g. thurberiae (thurberia weevil) subspecies. To validate the assay, we conducted three main experiments: (1) a sensitivity test to determine the DNA concentration range at which the assay performs, (2) a non-target specificity test to ensure no amplification in non-target weevils (false positives), and (3) an accuracy test comparing the results of the new assay to previously established methods. These experiments were carried out in parallel at three independent facilities to confirm the robustness of the assay to variations in equipment and personnel. We used DNA samples from various sources, including field-collected specimens, museum specimens, and previously isolated DNA. The assay demonstrated high sensitivity (PCR success with ≥0.05 ng/µL DNA template), specificity (0.02 false positive rate), and accuracy (97.7%) in diagnosing boll weevil and thurberia weevil subspecies. The entire workflow, including DNA extraction, assay preparation, PCR run time, and data analysis, can be completed within a single workday (7–9 h) by a single technician. The deployment of this assay as a diagnostic tool could benefit boll weevil management and eradication programs by enabling same-day diagnosis of trap-captured or intercepted weevil specimens. Furthermore, it offers a more reliable method for identifying unknown specimens, contributing to the overall effectiveness of boll weevil research and control efforts. [ABSTRACT FROM AUTHOR]

To effectively combat the re-infestation of boll weevils (Anthonomus grandis L.) in cotton fields, it is necessary to address the detection of volunteer cotton (VC) plants (Gossypium hirsutum L.) in rotation crops such as corn (Zea mays L.) and sorghum (Sorghum bicolor L.). The current practice involves manual field scouting at the field edges, which often leads to the oversight of VC plants growing in the middle of fields alongside corn and sorghum. As these VC plants reach the pinhead squaring stage (5–6 leaves), they can become hosts for boll weevil pests. Consequently, it becomes crucial to detect, locate, and accurately spot-spray these plants with appropriate chemicals. This paper focuses on the application of YOLOv5m to detect and locate VC plants during the tasseling (VT) growth stage of cornfields. Our results demonstrate that VC plants can be detected with a mean average precision (mAP) of 79% at an Intersection over Union (IoU) of 50% and a classification accuracy of 78% on images sized 1207 × 923 pixels. The average detection inference speed is 47 frames per second (FPS) on the NVIDIA Tesla P100 GPU-16 GB and 0.4 FPS on the NVIDIA Jetson TX2 GPU, which underscores the relevance and impact of detection speed on the feasibility of real-time applications. Additionally, we show the application of a customized unmanned aircraft system (UAS) for spot-spray applications through simulation based on the developed computer vision (CV) algorithm. This UAS-based approach enables the near-real-time detection and mitigation of VC plants in corn fields, with near-real-time defined as approximately 0.02 s per frame on the NVIDIA Tesla P100 GPU and 2.5 s per frame on the NVIDIA Jetson TX2 GPU, thereby offering an efficient management solution for controlling boll weevil pests.

Simple Summary: The boll weevil is a key pest of cotton in Central and South America. Its thermal requirements, development time, oviposition, survival, adult longevity, and sex ratio were determined under laboratory conditions, and the data were used to construct a fertility life table. Based on the results and a GIS (Geographic Information System), the R0 was estimated for different Brazilian regions and represented on a map. This information can be useful for developing strategies to manage the pest in cotton crops. The boll weevil, Anthonomus grandis grandis Boh., is the most important cotton pest in Central and South America. The biological characteristics and thermal requirements of boll weevils reared on an artificial diet were assessed at seven constant temperatures (18, 20, 22, 25, 28, 30, and 32 ± 1 °C) under laboratory conditions. These data were used to determine the ecological zoning for the pest in Brazil. The development time; oviposition period; the number of eggs produced; survival of eggs, larvae, and pupae; adult longevity; and sex ratio were recorded, and additional life table parameters were calculated. The total development duration ranged from 16.1 (32 °C) to 46.2 (18 °C) days. Temperature significantly affected the number of eggs laid per female (fecundity), with the highest number of eggs observed at 25 °C (251 ± 15.8). The parameters from the fertility life table indicated the greatest population growth at 25 °C and 28 °C. The net reproductive rate (R0) at these temperatures was 22.25 times higher than at 18 °C. Based on R0 and temperature, an ecological zoning of the pest was developed for Brazil. Brazilian regions with mean temperatures above 20 °C and below 30 °C are most favorable for the population growth of the boll weevil. The most suitable crop areas were found to be the north, midwest, and part of the northeast region, although the weevil can occur throughout Brazil if the host plants are available. [ABSTRACT FROM AUTHOR]

Simple Summary: The boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), is a pest of commercial cotton in the Americas. Eradication programs in the United States (USA) have been very successful and have reduced boll weevil occurrence to a small region in South Texas. The programs have relied almost exclusively on the chemical insecticide malathion for over forty years to treat boll weevils in the field. Despite this heavy selection pressure, the boll weevil remains susceptible to field application rates of this insecticide. Here, we present findings from an RNA-seq experiment documenting gene expression post-exposure to field-relevant concentrations of malathion, which was used to glean information about the boll weevil's continued susceptibility to this insecticide. Additionally, we incorporated whole genome sequence data from nearly 200 pest individuals obtained from three distinct geographical areas (Texas, Mexico, and Argentina) to determine SNP frequency in the malathion target site: acetylcholine esterase. No evidence was found from gene expression or single nucleotide polymorphism (SNP) data consistent with a mechanism of enhanced tolerance or resistance adaptation in the boll weevil, corroborating long-term field observations. Insecticide tolerance and resistance have evolved countless times in insect systems. Molecular drivers of resistance include mutations in the insecticide target site and/or gene duplication, and increased gene expression of detoxification enzymes. The boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), is a pest of commercial cotton and has developed resistance in the field to several insecticides; however, the current organophosphate insecticide, malathion, used by USA eradication programs remains effective despite its long-term use. Here, we present findings from an RNA-seq experiment documenting gene expression post-exposure to field-relevant concentrations of malathion, which was used to provide insight on the boll weevil's continued susceptibility to this insecticide. Additionally, we incorporated a large collection of boll weevil whole-genome resequencing data from nearly 200 individuals collected from three geographically distinct areas to determine SNP allele frequency of the malathion target site, as a proxy for directional selection in response to malathion exposure. No evidence was found in the gene expression data or SNP data consistent with a mechanism of enhanced tolerance or resistance adaptation to malathion in the boll weevil. Although this suggests continued effectiveness of malathion in the field, we identified important temporal and qualitative differences in gene expression between weevils exposed to two different concentrations of malathion. We also identified several tandem isoforms of the detoxifying esterase B1 and glutathione S-transferases, which are putatively associated with organophosphate resistance. [ABSTRACT FROM AUTHOR]

The boll weevil, Anthonomus grandis grandis Boheman, is one of the most historically impactful insects due to its near destruction of the US cotton industry in the early 20th century. Contemporary efforts to manage this insect primarily use pheromone baited traps for detection and organophosphate insecticides for control, but this strategy is not sustainable due to financial and environmental costs. We present a high-quality boll weevil genome assembly, consisting of 306 scaffolds with approximately 24,000 annotated genes, as a first step in the identification of gene targets for novel pest control. Gene content and transposable element distribution are similar to those found in other Curculionidae genomes; however, this is the most contiguous and only assembly reported to date for a member in the species-rich genus Anthonomus. Transcriptome profiles across larval, pupal, and adult life stages led to identification of several genes and gene families that could present targets for novel control strategies. [ABSTRACT FROM AUTHOR]

Growth-regulating insecticides are used for several cotton pests when immature, and although not registered for Anthonomus grandis , their use causes a satisfactory population reduction in adults. However, it is not known which mechanisms are involved in this reduction. Thus, we studied which tissue and cellular changes may be involved in this process. Adults were fed with flower buds treated with lufenuron (4 ml commercial product /l) for 24 h. Then, the histology of the gonads, oxidative stress and apoptosis were evaluated after periods of 24 h and 48 h. Our study revealed that lufenuron activates the oxidative stress pathway in A. grandis , causing significant changes at the cellular level. These changes may have been caused by stimulation of the production of oxygen ions, free radicals and hydrogen peroxides, resulting in an increase in lipid peroxidation 48 h after treatment. These effects were confirmed by the presence of histopathologies in the gonads of this pest such as disorganization of the follicular cell epithelium, reduction of the yolk, disappearance of the germinal vesicle, reduction of sperm bundles and cysts. Such alterations injured the gonads and impaired tissue homeostasis. It is concluded that together these factors lead to a desirable population reduction when it comes to managing the pest in the field, because the aim is to keep it below the control level. In addition to this desired effect, it is worth noting that lufenuron is safer when compared to other commonly used products, another feature that makes its use quite interesting. [ABSTRACT FROM AUTHOR]

Rapid and accurate identification of Anthonomus grandis subspecies is crucial for effective management and eradication. Current diagnostic methods have limitations in terms of time to diagnosis (up to seven days) and can yield ambiguous results. Here, we present the validation of a custom TaqMan SNP Genotyping Assay for the rapid and accurate identification of A. grandis grandis (boll weevil) and A. g. thurberiae (thurberia weevil) subspecies. To validate the assay, we conducted three main experiments: (1) a sensitivity test to determine the DNA concentration range at which the assay performs, (2) a non-target specificity test to ensure no amplification in non-target weevils (false positives), and (3) an accuracy test comparing the results of the new assay to previously established methods. These experiments were carried out in parallel at three independent facilities to confirm the robustness of the assay to variations in equipment and personnel. We used DNA samples from various sources, including field-collected specimens, museum specimens, and previously isolated DNA. The assay demonstrated high sensitivity (PCR success with ≥0.05 ng/µL DNA template), specificity (0.02 false positive rate), and accuracy (97.7%) in diagnosing boll weevil and thurberia weevil subspecies. The entire workflow, including DNA extraction, assay preparation, PCR run time, and data analysis, can be completed within a single workday (7–9 h) by a single technician. The deployment of this assay as a diagnostic tool could benefit boll weevil management and eradication programs by enabling same-day diagnosis of trap-captured or intercepted weevil specimens. Furthermore, it offers a more reliable method for identifying unknown specimens, contributing to the overall effectiveness of boll weevil research and control efforts.

The feral or volunteer cotton (VC) plants when reach the pinhead squaring phase (5–6 leaf stage) can act as hosts for the boll weevil (Anthonomus grandis L.) pests. The Texas Boll Weevil Eradication Program (TBWEP) employs people to locate and eliminate VC plants growing by the side of roads or fields with rotation crops but the ones growing in the middle of fields remain undetected. In this paper, we demonstrate the application of computer vision (CV) algorithm based on You Only Look Once version 5 (YOLOv5) for detecting VC plants growing in the middle of corn fields at three different growth stages (V3, V6 and VT) using unmanned aircraft systems (UAS) remote sensing imagery. All the four variants of YOLOv5 (s, m, l, and x) were used and their performances were compared based on classification accuracy, mean average precision (mAP) and F1-score. It was found that YOLOv5s could detect VC plants with maximum classification accuracy of 98% and mAP of 96.3% at V6 stage of corn while YOLOv5s and YOLOv5m resulted in the lowest classification accuracy of 85% and YOLOv5m and YOLOv5l had the least mAP of 86.5% at VT stage on images of size 416 × 416 pixels. The developed CV algorithm has the potential to effectively detect and locate VC plants growing in the middle of corn fields as well as expedite the management aspects of TBWEP.

The boll weevil, Anthonomus grandis grandis Boh., is the most important cotton pest in Central and South America. The biological characteristics and thermal requirements of boll weevils reared on an artificial diet were assessed at seven constant temperatures (18, 20, 22, 25, 28, 30, and 32 ± 1 °C) under laboratory conditions. These data were used to determine the ecological zoning for the pest in Brazil. The development time; oviposition period; the number of eggs produced; survival of eggs, larvae, and pupae; adult longevity; and sex ratio were recorded, and additional life table parameters were calculated. The total development duration ranged from 16.1 (32 °C) to 46.2 (18 °C) days. Temperature significantly affected the number of eggs laid per female (fecundity), with the highest number of eggs observed at 25 °C (251 ± 15.8). The parameters from the fertility life table indicated the greatest population growth at 25 °C and 28 °C. The net reproductive rate (R0) at these temperatures was 22.25 times higher than at 18 °C. Based on R0 and temperature, an ecological zoning of the pest was developed for Brazil. Brazilian regions with mean temperatures above 20 °C and below 30 °C are most favorable for the population growth of the boll weevil. The most suitable crop areas were found to be the north, midwest, and part of the northeast region, although the weevil can occur throughout Brazil if the host plants are available.

A synthetic approach to grandisol is described. The route to the cyclobutane core relies on an efficient intramolecular [2+2] cyclo-addition that establishes the required cis -ring fusion at the adjacent side chains of the cyclobutane ring. Using a new two-step lithium/halide homologation procedure, norgrandisol was efficiently converted into grandisol. This new approach enables the synthesis of grandisol in five steps from commercially available starting material in 22% overall yield. [ABSTRACT FROM AUTHOR]

Abstract The boll weevil, Anthonomus grandis Boheman (Coleoptera: Curculionidae), is an important pest of commercial cotton across the Americas. In the United States, eradication of this species is complicated by re‐infestations of areas where eradication has been previously successful and by the existence of morphologically similar variants that can confound identification efforts. To date, no study has applied a high‐throughput sequencing approach to better understand the population genetic structure of the boll weevil. Furthermore, only a single study has investigated genetic relationships between populations in North and South America. We used double digest restriction site‐associated DNA sequencing (ddRADseq) to resolve the population genomic structure of the boll weevil in the southern United States, northern Mexico, and Argentina. Additionally, we assembled the first complete mitochondrial genome for this species and generated a preliminary whole genome assembly, both of which were used to improve the identification of informative loci. Downstream analyses revealed two main lineages—one consisting of populations found geographically west of the Sierra Madre Occidental mountain range and the second consisting of populations found to the east—were revealed, and both were sub‐structured. Population geographic structure was consistent with the isolation by distance model, indicating that geogrpahic distance is likely a primary mechanism driving divergence in this species. Boll weevil populations from Argentina were found to be more closely related to the eastern lineage, suggesting a recent colonization of South America by the eastern lineage, but additional sampling across Mexico, Central America and South America is needed to further clarify their origin. Finally, we uncovered an instance of population turnover or replacement, highlighting the temporal instability of population structure.

Insecticide tolerance and resistance have evolved countless times in insect systems. Molecular drivers of resistance include mutations in the insecticide target site and/or gene duplication, and increased gene expression of detoxification enzymes. The boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), is a pest of commercial cotton and has developed resistance in the field to several insecticides; however, the current organophosphate insecticide, malathion, used by USA eradication programs remains effective despite its long-term use. Here, we present findings from an RNA-seq experiment documenting gene expression post-exposure to field-relevant concentrations of malathion, which was used to provide insight on the boll weevil’s continued susceptibility to this insecticide. Additionally, we incorporated a large collection of boll weevil whole-genome resequencing data from nearly 200 individuals collected from three geographically distinct areas to determine SNP allele frequency of the malathion target site, as a proxy for directional selection in response to malathion exposure. No evidence was found in the gene expression data or SNP data consistent with a mechanism of enhanced tolerance or resistance adaptation to malathion in the boll weevil. Although this suggests continued effectiveness of malathion in the field, we identified important temporal and qualitative differences in gene expression between weevils exposed to two different concentrations of malathion. We also identified several tandem isoforms of the detoxifying esterase B1 and glutathione S-transferases, which are putatively associated with organophosphate resistance.

Decision making in pest management is a challenging task. While pest dynamics are often quite uncertain, such decisions are often based on tenuous assumptions of certainty (economic injury levels and marginal utility approximations). To overcome such assumptions and adequately consider uncertainty, we apply decision analysis to evaluate management strategies used by farmers in the Colombian Caribbean against the boll weevil (BW). We represent the decision to protect the crop using partial budget analysis. This allows us to capture key properties of BW control strategies, while accounting for uncertainty about pest infestation pressure, control effectiveness and cotton yield and price. Our results indicate that proactive pest management is more efficient than reactive control given the current BW infestation pressure. However, farmers may prefer the reactive strategy, since they have experienced seasons with low infestation pressure where no insecticide applications were required. The proactive strategy, in contrast, requires scheduled pesticide applications in all years. Results show that in seasons with high infestation pressure the expected revenues of the reactive strategy tend to decrease, mainly because more spray applications are required when fields are heavily infested by the weevil. Value of information analysis revealed that uncertainties related to the start of the infestation, loss damage rate and attainable yield have the greatest influence on the decision recommendation for crop protection. Narrowing these key knowledge gaps may offer additional clarity on the performance of the current management strategies and provide guidance for the development of strategies to reduce insecticide use. This is particularly important for the promotion of the proactive strategy, which, under the current infestation pressure, has potential to reduce insecticide use. While economic injury levels can only be applied to responsive measures, our approach of partial budget analysis under uncertainty allows us to assess and compare both responsive and preventive measures in the same methodological framework. This framework can be extended to non-pesticide control measures. [ABSTRACT FROM AUTHOR]

Background. Resistance to an insecticide is what determines its effectiveness and the lack of information limits effectiveness in the control of the boll weevil in cotton crops. Objective. The objective of the study was to determine the susceptibility of the boll weevil (Anthonomus grandis Boheman) to malathion in the Laguna, Mexico. Currently, this pest is considered as the one with the highest economical impact on cotton cultivation in the region. Methodology. Three bioassays were carried out, one in the state of Coahuila in the 2017 agricultural season and in the 2018 and 2019 seasons in the states of Coahuila and Durango. Boll weevils reared in the laboratory, as well as those collected in the field were used to obtain DL50 and DL95. The mortality data was analyzed using the Probit analysis. Results. The mean lethal dose after 48 hours in the three agricultural cycles fluctuated between 0.19 and 0.39 µg/µl for adults raised in the laboratory and the data observed for adults collected in the field was between 0.37 and 0.44 µg/µl. Implications. Periodic bioassays are suggested to detect populations resistant to malathion. Conclusion. It was determined that the boll weevil populations in the Laguna Region were susceptible to malathion, since the mean lethal dosage for the 3 agricultural seasons was < 1 µg/µl.

The boll weevil, Anthonomus grandis Boheman (Coleoptera: Curculionidae), is an important pest of commercial cotton across the Americas. In the United States, eradication of this species is complicated by re‐infestations of areas where eradication has been previously successful and by the existence of morphologically similar variants that can confound identification efforts. To date, no study has applied a high‐throughput sequencing approach to better understand the population genetic structure of the boll weevil. Furthermore, only a single study has investigated genetic relationships between populations in North and South America. We used double digest restriction site‐associated DNA sequencing (ddRADseq) to resolve the population genomic structure of the boll weevil in the southern United States, northern Mexico, and Argentina. Additionally, we assembled the first complete mitochondrial genome for this species and generated a preliminary whole genome assembly, both of which were used to improve the identification of informative loci. Downstream analyses revealed two main lineages—one consisting of populations found geographically west of the Sierra Madre Occidental mountain range and the second consisting of populations found to the east—were revealed, and both were sub‐structured. Population geographic structure was consistent with the isolation by distance model, indicating that geogrpahic distance is likely a primary mechanism driving divergence in this species. Boll weevil populations from Argentina were found to be more closely related to the eastern lineage, suggesting a recent colonization of South America by the eastern lineage, but additional sampling across Mexico, Central America and South America is needed to further clarify their origin. Finally, we uncovered an instance of population turnover or replacement, highlighting the temporal instability of population structure. [ABSTRACT FROM AUTHOR]

This essay addresses the public memory of the Boll Weevil Monument in Enterprise, Alabama, as an exemplar of Southern liberal kitsch, a memory practice articulating regional identity through a playful discourse of progress that secures whiteness and deflects confrontation with historical racial injustice. Through a combination of archival research and fieldwork during the centennial celebration of the Boll Weevil Monument in 2019, I identify three rhetorical quirks underwriting Boll Weevil public memory that inform broader efforts to reimagine the past in greater service to contemporary political exigencies. Editor Content Warning: This essay contains descriptions of racial violence. [ABSTRACT FROM AUTHOR]

The boll weevil [BW; Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae)] is the main pest in the cotton-producing regions throughout the Americas from Southern Texas to Argentina. In the Colombian Caribbean, frequent population outbreaks have resulted in cotton planting bans in some localities and in massive applications of insecticides elsewhere (up to 15 insecticide sprays per cotton season). To date, information on boll weevil management strategies in Colombia is only available in the forms of gray literature (technical reports) and informal knowledge held by crop advisors and farmers. This study compiles this information using a standardized protocol for participatory construction of conceptual models for agricultural systems. The conceptual model developed in this study integrates the informal local knowledge of crop advisors and farmers with disciplinary knowledge describing management strategies for boll weevil. The collected data were assessed and organized using a systems approach to facilitate the future development of quantitative models and allow visualization of knowledge gaps. The model includes the description of the biological and technical-decisional subsystems. The latter subsystem explains boll weevil management at two temporal-spatial scales: 1) farm (field) scale management during the cotton season and 2) a regional boll weevil suppression strategy mainly aimed at controlling the insect populations that survived the intercotton season. The development of this conceptual model allowed describing the current management strategies for boll weevil and formulating hypotheses about the effectiveness of these strategies. This conceptual model provides guidelines for future research, and it can serve as a baseline for the development of quantitative models and simulations describing the decision-making process related to the management of boll weevil in the Colombian Caribbean. [ABSTRACT FROM AUTHOR]

The boll weevil spread across the South from 1892 to 1922 with devastating effect on cotton cultivation. The resulting shift away from this child labor–intensive crop lowered the opportunity cost of school attendance. We investigate the insect's long-run effect on educational attainment using a sample of adults from the 1940 census linked back to their childhood census records. Both white and black children who were young (ages 4 to 9) when the weevil arrived saw increased educational attainment by 0.24 to 0.36 years. Our results demonstrate the potential for conflict between child labor in agriculture and educational attainment. [ABSTRACT FROM AUTHOR]

In the last years, the production of ethanol fuel has started to change with the introduction of second-generation ethanol (2 G Ethanol) in the energy sector. However, in Brazil, the process of obtaining 2 G ethanol did not reach a basic standard to achieve relevant and economically viable results. Several studies have currently been addressed to solve these issues. A critical stage in the bioethanol production is the deployment of efficient and stable enzymes to catalyze the saccharification step into the process of biomass conversion. The present study comprises a screening for genes coding for plant biomass degradation enzymes, followed by cloning a selected gene, addressing its heterologous expression, and characterizing enzymatic activity towards cellulose derived substrates, with a view to second-generation ethanol production. A cDNA database of the Cotton Boll Weevil, Anthonomus grandis (Coleoptera: Curculionidae), an insect that feeds on cotton plant biomass, was used as a source of plant biomass degradation enzyme genes. A larva and adult midgut-specific β-1,4-Endoglucanase-coding gene (AgraGH45-1) was cloned and expressed in the yeast Pichia pastoris. Its amino acid sequence, including the two catalytic domains, shares high identity with other Coleoptera Glycosyl Hydrolases from family 45 (GH45). AgraGH45-1 activity was detected in a Carboxymethylcellulose (CMC) and Hydroxyethylcellulose (HEC) degradation assay and the optimal conditions for enzymatic activity was pH 5.0 at 50 °C. When compared to commercial cellulase from Aspergillus niger, Agra GH45-1 was 1.3-fold more efficient to degrade HEC substrate. Together, these results show that AgraGH45-1 is a valid candidate to be engineered and be tested for 2 G ethanol production. [ABSTRACT FROM AUTHOR]

Eradication programs for the boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), rely almost exclusively on pheromone traps to indicate the need for insecticide applications. However, the effectiveness of traps in detecting weevil populations is reduced during certain times of the year, particularly when cotton is actively fruiting. Consequently, this could result in fields becoming heavily infested with weevils. It is widely speculated that the lack of weevil captures in traps during this period is largely due to the overwhelming amount of pheromone released by weevils in the field, which outcompete the pheromone released from traps. Thus, this work sought to identify genes involved in pheromone production so that new control methods that target these genes can be explored. We conducted an RNA-seq experiment that revealed 2479 differentially expressed genes between pheromone-producing and non-pheromone-producing boll weevils. Of those genes, 1234 were up-regulated, and 1515 were down-regulated, and most had gene annotations associated with pheromone production, development, or immunity. This work advances our understanding of boll weevil pheromone production and brings us one step closer to developing gene-level control strategies for this cotton pest.

The boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), is a major pest of cotton (Gossypium spp. (Malvales: Malvaceae)) in Mexico, South America, and South Texas in the United States. The ability of the boll weevil to survive extended cotton-free periods has been key to its persistence as a pest despite intensive control efforts. However, the mechanism facilitating survival has been subject to debate. Whereas adult diapause has long been considered the principal survival mechanism, some authors have characterized the dormancy as a quiescence. We induced dormancy in the weevil and examined whether food type, enforced starvation, or induced flight influenced termination of the dormancy. Providing dormant adult weevils a diet favoring reproduction for 7–14 d prompted a modest termination response in female weevils and virtually no response in males. Some weevils starved ≥21 d resumed reproduction after exposure to a favorable diet, but most weevils remained dormant. Induced flight followed by exposure to a favorable diet prompted >50% of the weevils to terminate the dormancy. Patterns of feeding and oviposition were also useful in interpreting the termination response. These results indicate that the dormancy exhibited by the weevil is a diapause of variable intensity rather than a quiescence. A conceptual model recognizing population heterogeneity in diapause induction and intensity is consistent with reports of host-free survival and accommodates perceived differences in boll weevil ecology among temperate, subtropical, and tropical regions. This model provides a framework that will be valuable to research, management, and eradication efforts in the tropics and subtropics. [ABSTRACT FROM AUTHOR]

Insect-derived volatiles seem to provide reliable chemical cues that plants could employ to defend themselves. Here we investigated the effect of pheromone emission from a closely associated (Anthonomus grandis ; boll weevil) and an unassociated (Tibraca limbativentris) herbivore on cotton volatile emission. Exposure to A. grandis aggregation pheromone induced cotton defence response by enhancing the emission of volatiles attractive to the natural enemy of A. grandis, the parasitic wasp Bracon vulgaris, but only when the pheromonal blend was complete (all four components). Individual components of A. grandis aggregation pheromone were not able to induce cotton plants to increase the release of volatiles. On the other hand, T. limbativentris sex pheromone did not induce any change in the cotton constitutive volatile profile. Our results support the hypothesis that plants are able to detect pheromones of tightly co-evolved herbivores. Moreover, A. grandis pheromone exposure induced similar volatile compounds to herbivore-induced cotton, such as linalool, (E)-ocimene, (E)-4,8-dimethylnona-1,3,7-triene (DMNT), and (E,E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT). We also showed that the larval ectoparasitoid B. vulgaris relies on boll weevil's aggregation pheromone and pheromone-induced plant volatiles as kairomones to locate suitable hosts. [ABSTRACT FROM AUTHOR]