About

Dr. Michael J. Brewer is a professor specializing in entomology with a focus on sustainable pest management in large-scale field crop agroecosystems. His research addresses the challenges posed by invasive pests and ongoing pest invasions affecting U.S. agriculture, particularly in crops such as sorghum, cotton, and maize. Dr. Brewer's work aims to develop sustainable and area-wide approaches to managing pests by increasing understanding of plant-insect-natural enemy interactions and pest regulation mechanisms that influence pest outbreak severity and control. A significant part of his research involves an areawide pest management project targeting the invasive sorghum aphid Melanaphis sorghi, where his findings have demonstrated that natural enemies such as aphid predators and parasites play a critical role in reducing pest damage risk. This research has contributed to regional risk assessments and the development of local pest management tools, including the use of resistant sorghum hybrids and economic thresholds to guide insecticide applications, resulting in substantial economic savings for growers in South Texas.

Research topics

• Biology
• Ecology
• Agronomy
• Botany
• Horticulture
• Agroforestry
• Geography
• Toxicology
• Statistics
• Mathematics

Selected publications

• <i>Aspergillus flavus</i> populations in matrices of the corn agroecosystem

  Plant Disease · 2026-05-07

  article

  Infection of corn by the pathogen Aspergillus flavus can result in the contamination of the grain with aflatoxin, a potent, regulated mycotoxin. A. flavus has high genetic diversity, even within a single field, but it is unknown if the population is homogenous among the different matrices of the corn agroecosystem or if there are discernable subpopulations. We collected isolates of A. flavus from two sites for two years from soil, grain, corn silks, and Helicoverpa zea moths and larvae. This collection of over 1000 isolates of A. flavus were screened and characterized based upon aflatoxigenic potential, sclerotial morphotype and 17 simple sequence repeat (SSR) markers. The collection from the Corpus Christi, Texas study site had a higher frequency of aflatoxigenic isolates than the collection from Stoneville, Mississippi. The genotype of a commercially available biocontrol isolate of A. flavus was present at both study sites, but was 5 times more abundant at Stoneville, Mississippi than at Corpus Christi, Texas. SSR-based population genetics indicated that the A. flavus populations collected from various matrices were not differentiated and that there appeared to be significant gene flow among the populations within each site.

  PublisherDOI

• Effect of Transgenic Cotton with Bt Event Mpp51Aa2 on Cotton Fleahopper (Pseudatomoscelis seriatus) During Early Cotton Growth and Resulting Plant Injury

  Insects · 2026-02-24

  articleOpen accessSenior author

  (Reuter)) is an early-season hemipteran plant bug pest of cotton. In transgenic cotton cultivars, Bt event Mpp51Aa2 (Cry51Aa2) affects some other plant bug species (Hemiptera: Miridae) (we henceforth use the common terminology, stating that these cultivars have the ThryvOn trait). Field experiments were conducted in Corpus Christi, Texas, USA, to evaluate the responses of four cotton cultivars with and without the ThryvOn trait to cotton fleahopper infestations, comparing them with early-season foliar insecticide applications of flupyradifurone. Naturally occurring cotton fleahopper populations rose to the economic threshold midway through the first four weeks of squaring, when cotton plants are most sensitive to feeding injury, in 2024 and later in the same period in 2025. Flupyradifurone application significantly reduced adult and nymph abundance, resulting in reduced square abscission (2025) and yield protection that was consistent across cultivars in 2024 but more variable in 2025. Cultivars expressing the ThryvOn trait exhibited modest and variable reductions in adult cotton fleahopper abundance (~10-30%), occasionally benefiting from reduced square abscission but not protected yield. The open boll ratio, used to assess maturity delay, was not affected by cultivar or cotton fleahopper pressure. These results indicate that ThryvOn cultivars may provide limited supplemental benefits but do not replace or enhance the effectiveness of flupyradifurone for cotton fleahopper management.

  PublisherDOI

• 1693: VA ECMO FOR MASSIVE/HIGH-RISK PULMONARY EMBOLISM: OUTCOMES FROM AN INTENSIVIST-LED ECMO PROGRAM

  Critical Care Medicine · 2025-01-01

  article1st authorCorresponding
  PublisherDOI

• Activity of sorghum aphid and its natural enemies in the context of agroecological and weather conditions

  Frontiers in Insect Science · 2025-02-10 · 2 citations

  articleOpen access

  Agroecological-oriented areawide pest management leverages the innate ability of agroecosystem to suppress pests, and thus to utilize ecosystem services, a key component of sustainable agriculture. A growing body of knowledge on interactions between pests and their natural enemies allows us to recognize the complexity of these interactions that often depend on environmental circumstances. Sorghum aphid, Melanaphis sorghi (Theobald) (Hemiptera: Aphididae), is a recent but established pest of sorghum in the Great Plains of North America. Both predators and parasitoids prey on sorghum aphid but their activity and impact change throughout the area and throughout the year. Both landscape and weather factors have been shown to affect the abundance and numerical responses of these insects, consistent with observations in other aphid species. In this study we used data on counts of sorghum aphids, lady beetles (Coleoptera: Coccinellidae), and parasitoid wasps Aphelinus nigritus Howard (Hymenoptera: Aphelinidae) and Lysiphlebus testaceipes (Cresson) (Hymenoptera: Braconidae) collected in Kansas, Oklahoma and Texas states of the United States. We analyzed insect dynamics in the context of landscape and weather factors. We built multiple regression models using data from the years 2017–2019 for metrics such as maximum number of insects per leaf, response time of natural enemies to pest presence, and speed of increase in insect abundance. Our results indicate that various aspects of landscape composition, landscape configuration, and weather affect various insect groups and various aspects of insect dynamics in the field. Moreover, characteristics of specific landscape categories seemed to be more informative than overall measure of landscape diversity. Our study provides insights on interactions along both spatial and temporal scales, with the latter considered understudied.

  PublisherDOI

• Response of cotton cultivars with varying maturity traits to cotton fleahopper (Hemiptera: Miridae) feeding

  Journal of Economic Entomology · 2025-05-07 · 1 citations

  articleSenior author

  Cotton fleahopper, Pseudatomoscelis seriatus Reuter (Hemiptera: Miridae), is an early season pest of upland cotton, Gossypium hirsutum L. Feeding damage from this pest causes square abscission. The response of commercial cotton cultivars with varying maturity traits to cotton fleahopper feeding was assessed. The hypothesis was that feeding affects early and late-maturing cultivars differently in maturity delays and yield. Field experiments with natural and artificial infestations were conducted in Corpus Christi, TX. For the natural infestation experiment, 4 cultivars (DP 2020 B3XF, DP 2012 B3XF, PHY 332 W3FE, and PHY 545 W3FE) were assigned to main plots, with subplots either sprayed or not sprayed with thiamethoxam insecticide to control cotton fleahopper early in the season. The artificial infestation experiment used 2 cultivars (DP 2020 B3XF and PHY 545 W3FE) as main plots, with subplots infested to or not infested with cotton fleahopper using single square caging. In the no-spray subplots of the natural infestation experiment, cotton fleahopper feeding increased square abscission, leading to yield loss and delayed boll maturity, especially in cultivars classified as late-maturing. Early maturing cultivars consistently showed faster boll opening regardless of cotton fleahopper. Artificial infestation experiments further confirmed increased square abscission, reduced boll numbers, and lower lint weights when infested with cotton fleahopper. Early maturing cultivars are more resilient and may be particularly useful in areas with high cotton fleahopper pressure, especially when scheduling an early harvest is desirable.

  PublisherDOI

• Detection, quantification, and characterization of airborne Aspergillus flavus within the corn canopy

  Mycotoxin Research · 2025-01-14 · 1 citations

  articleOpen access

  Aflatoxin contamination of corn can occur when developing kernels are infected by the plant pathogen Aspergillus flavus. One route of infection is from airborne conidia. We executed a series of experiments within the corn canopy during two growing seasons and in two states to document the abundance and dynamics of the airborne A. flavus population. We did not observe any significant diurnal changes in the conidial density (p = 0.171) or any effect of sampler height (p = 0.882) within the canopy. Significant changes (p < 0.001) were noted during the season, with a trend towards increased airborne populations with later stages of corn development and more than a 20-fold increase from July to August. The median aflatoxigenicity of airborne isolates from a corn canopy in Texas was about 50 times higher than the corresponding population in Mississippi. It was also noteworthy that highly aflatoxigenic, weakly sporulating S-morphotypes accounted for 14-30% of the airborne isolates in Mississippi at a site with historically rare abundance of S-morphotypes. The genetic diversity was high among the 140 analyzed airborne isolates, with 76 unique haplotypes identified and 55 haplotypes occurring only in 1 isolate. Even in the context of this highly diverse population, a haplotype matching that of a commercial biocontrol strain was found in 13 of the 70 isolates from Mississippi and 1 of the 70 isolates from Texas. The airborne A. flavus population is genetically diverse (Shannon's index = 1.4 to 1.6), similar to grain samples in other surveys, and much less aflatoxigenic in Mississippi than in Texas.

  PublisherOA PDFDOI

• Leaffooted Bugs, Leptoglossus phyllopus (Hemiptera: Coreidae), Are Attracted to Volatile Emissions from Herbivore-Damaged Cotton Bolls

  Insects · 2025-04-17

  articleOpen accessSenior author

  The leaffooted bug, Leptoglossus phyllopus (L.) (Hemiptera: Coreidae), probes and feeds on tissues of many plant species, including developing cotton bolls, causing seed damage and abscission. Insecticides are the primary tool for managing leaffooted bugs, but concerns about resistance and environmental harm highlight the need for alternative management strategies. One promising approach is using semiochemicals, such as plant- and insect-produced volatile organic compounds (VOCs), to trap or repel pests. Insect herbivores often use plant-produced VOCs to select suitable host plants for feeding and oviposition. Field observations of abundant adult leaffooted bugs on cotton bolls suggest that bugs aggregate at feeding sites. The goal of this study was to characterize VOCs from developing cotton bolls with and without leaffooted bug herbivory and evaluate how these VOCs affect adult bug foraging behavior. A portable dynamic headspace sampling method was used to collect VOCs from developing cotton bolls in the field, and VOC samples were analyzed using gas chromatography–mass spectrometry. Leaffooted bug herbivory induced volatile emissions from cotton bolls, with significant increases in the emissions of six compounds (benzaldehyde, α-pinene, β-pinene, β-myrcene, p-xylene, and (E)-β-caryophyllene). Dual-choice olfactometer assays revealed that adult leaffooted bugs were attracted to VOCs from damaged cotton bolls, as well as being attracted to synthetic benzaldehyde or α-pinene individually. In contrast, leaffooted bugs were repelled by the combination of synthetic benzaldehyde and α-pinene. These findings suggest that VOCs from cotton bolls are attractive to leaffooted bugs and could contribute to the development of attractive lures for integrated pest management.

  PublisherDOI

• Cotton Fleahopper Herbivory on Cotton Squares Induces Plant Volatile Emissions that Repel Conspecifics

  Journal of Chemical Ecology · 2025-05-24 · 1 citations

  articleSenior author
  PublisherDOI

• Editorial: Areawide pest management and agroecosystem resilience to suppress invasive insects

  Frontiers in Insect Science · 2025-04-24 · 1 citations

  editorialOpen access1st authorCorresponding

  pest populations reduces the likelihood and severity of reintroduction from source hosts (crop and non-crop). This concept is particularly applicable to invasive species that enter into an agroecosystem with attributes beneficial to pest biology and depauperate of suppression agents, resulting in substantial agricultural disruption over a large area (Faust 2008). Further, an areawide approach may support IPM strategies by reducing the abundance of key pest populations at broader geographic scales thereby enabling the management of secondary pests with non-chemical approaches. This research topic extends this concept to address spatial variability of invasive as well as perennial pests and their suppression agents such as natural enemies. Traditionally, spatial and temporal variations of pest populations, including invasive species, have been documented along temperature gradients and among different crops and cultivars of a crop in the IPM literature (Kogan 1998), and through the action of natural enemies (Bellows et al. 1999). More recently in the expanding agroecology literature, the influence of additional landscape elements on pests and natural enemies has been considered (Dorman et al. 2020, Jeanneret et al. 2021).An agroecosystem orientation for management of invasive species becomes more valuable when source-sink insect dynamics, insect movement, habitat affiliation, pest suppression agents, and crop sensitivity to the pest vary spatially across a crop production region (Brewer and Elliott 2023). This variability is consistent with the viewpoint that pest and natural enemy abundance and species diversity are spatially variable and conditional on the range of agricultural (inclusive of crop genetics, crop field size and shape, and crop diversity) and environmental (inclusive of weather and climate, and local to regional semi-natural vegetative structure) conditions that themselves vary in the landscape (Karp et al. 2018, Dorman et al. 2021, 2024, Brewer and Elliott 2023). Overall, the goal of this research topic is to document examples of areawide pest management approaches to assess pest risk along with pest suppression that is naturally occurring in an agroecosystem and target insertion of areawide pest management practices that improve pest suppression.As an example, the landscape and weather of an agroecosystem are spatially and temporarily heterogeneous in the North American Great Plains even though a few cereal crops dominate the cropping system. This off-crop heterogeneity is associated with varying capacity to suppress several cereal aphid invaders (Brewer et al. 2019) and most recently the sorghum aphid, Melanaphis sorghi (Hemiptera: Aphididae) (Brewer et al. 2022, this RT). Using spatially explicit ecological modeling in this system, Koralewski et al. (2025, this RT) found the extent and form of heterogeneity are relevant to natural pest suppression, including landscape elements, weather conditions, and the temporal sequence of arrival of mobile aphids and activity of their natural enemies. In considering weather and insect movement across a large grass seed and vegetable agroecosystem, Slone et al. (2025, this RT) focused on Agrotis ipsilon (Lepidoptera: Noctuidae).The spatiotemporal occurrence of A. ipsilon was forecast using phenological models taking into account temperature-dependent population growth which varies by crop host and the moth's migratory behavior across the system. Brewer (2024, this RT) working in the cotton agroecosystem further demonstrated that distance metrics (nearest distance of non-crop habitat of pests to cotton fields) were useful in evaluating early season risk of a plant bug, Creontiades signatus (Hemiptera: Miridae), infesting cotton. The value of distance was previously used to recommend planting distances of cotton to alfalfa as a means to reduce the threat of another mirid species, Lygus hesperus, infesting cotton from source alfalfa fields that when cut induced movement of L. herperus to nearby cotton fields (Carriere et al. 2006). In these examples, the associations with spatially variable pest abundance were revealed by applying landscape ecology 4 principles and advances in geographic information systems (GIS) to archive, manipulate, and analyze spatial insect, landscape, and weather data, with key associations verified by experimental manipulation when possible.Regarding the application of management practices areawide, Herreid et al. (2024, this RT) used a simple agronomic harvest practice in alfalfa hay production (i.e., cutting the first hay crop early) to suppress alfalfa weevil, Hypera postica (Coleoptera: Curculionidae). Cutting alfalfa early decreased weevil populations directly with no apparent disruption to parasitism rates of alfalfa weevil through the harvest event. Hypera postica and its Ichneumonid parasitoid are common across the Intermountain western United States, providing the rationale for applying early first cut of hay areawide. Additional examples can be found in the areawide pest management literature (e.g., Koul et al. 2008) and literature focusing on specific pest suppression techniques applied areawide (e.g., Dyck et al. 2005).We hope the articles posted to this Research Topic stimulate further research into using spatial information of landscape, weather, and pest suppression agents to assess pest risk regionwide and target insertion of areawide pest management practices that improve pest suppression where it is lacking in the near-term and may bolster agroecosystem resilience to pests in the long-term.Author contributions MB: Writingoriginal draft, Writingreview & editing. SD: Writingreview & editing.

  PublisherOA PDFDOI

• Integrated Pest Management, Ecoliteracy, and Unexpected Consequences

  2024-09-12

  book-chapterSenior author

  The roots of Integrated Pest Management (IPM) are deeply embedded within the land grant university system. IPM evolved during the last four decades of the twentieth century in response to the unexpected consequences associated with the Synthetic Pesticide Era of pest management. IPM has become both the national and global standard. The goal of this chapter is to describe the nature and current practice of IPM, and to illustrate its value in the enhancement of ecoliteracy. We also describe how the philosophy, process, and practices of IPM can be used to significantly reduce patterns of risk and unexpected consequences associated with ecosystem management decisions. An important part of the Sustainable Agriculture Research and Education (SARE)–funded research has dealt with weed and insect management using principles of IPM.

  PublisherDOI

Frequent coauthors

• Norman C. Elliott

  46 shared

• Isaac L. Esquivel

  27 shared

• James P. Glover

  Southern Research Station

  19 shared

• Michael J. Starek

  Texas A&M University – Corpus Christi

  17 shared

• Ashleigh M. Faris

  Oklahoma State University

  16 shared

• Hsiao‐Hsuan Wang

  Texas A&M University

  15 shared

• Tomasz E. Koralewski

  Texas A&M University

  14 shared

• William E. Grant

  Texas A&M University

  14 shared

Labs

• Michael J. Brewer LabPI

Education

• Ph.D., Entomology

  University of California Riverside

  1990