About

Robert Koch is an Interim Department Head and Professor in the Department of Entomology at the University of Minnesota. He holds a B.A. in Biology from St. John’s University and a Ph.D. in Entomology from the University of Minnesota. His research program focuses on applied ecology and integrated pest management of arthropods associated with soybean. The goal of his research, in conjunction with his extension program, is to improve the environmental and economic sustainability of crop production through integrated pest management. His work emphasizes pest biology, evaluation and integration of management tactics, and scouting and decision making. Through extension programming, Robert Koch provides research-based guidance to farmers and agricultural professionals for managing soybean pests. He leads efforts to connect agricultural professionals with the latest crop research via the Institute for Agricultural Professionals, which includes educational events such as the Field School for Ag Professionals, the Crop Pest Management Short Course, and Research Updates for Ag Professionals. His contributions have been recognized with numerous awards, including the Award of Excellence in Integrated Pest Management, the Distinguished Extension and Outreach Award, and the International IPM Award of Excellence for Teams. He has advised multiple graduate students and collaborates with staff and researchers to advance integrated pest management practices.

Research topics

• Biology
• Ecology
• Botany
• Artificial Intelligence
• Agronomy
• Computer Science
• Genetics
• Zoology
• Toxicology

Selected publications

• Impact of foliar insecticides on soybean aphid, 2024

  Arthropod management tests · 2025-01-01

  articleOpen accessSenior author
  PublisherDOI

• Potential of Relay-Cropping Soybean (Fabales: Fabaceae) with a Pennycress (Brassicales: Brassicaceae) Cover Crop to Suppress Soybean Aphid (Hemiptera: Aphididae) Populations

  Journal of Entomological Science · 2025-12-09

  articleSenior author
  PublisherDOI

• Spatial and temporal dynamics of leaf injury from Macrosaccus morrisella in soybean

  Crop Protection · 2025-07-15

  articleSenior author
  PublisherDOI

• The genome sequence and genomic diversity of soybean tentiform leafminer (<i>Macrosaccus morrisella</i>)

  G3 Genes Genomes Genetics · 2025-02-04 · 1 citations

  articleOpen accessSenior author

  The soybean tentiform leafminer, Macrosaccus morrisella (Fitch) (Lepidoptera: Gracillariidae), is native to North America where it was known to feed on American hogpeanut and slickseed fuzzybean. However, it has recently expanded its host range to include soybean, an important agricultural crop. Here, we report a new, highly contiguous genome for this species with a length of 245 Mb, N50 of 9 Mb, and 96.33% BUSCO completeness. The mitochondrial genome shares only 81% identity to its nearest relative in the NCBI nucleotide database indicating long-standing divergence or sparse sequencing in this clade. To determine whether host plant choice is genetically driven, we sequenced 18 individuals across 3 locations in Minnesota, USA, collected from both American hogpeanut and soybean plants. Genetic variation did not correlate with population structure based on either geography or host plant species (weighted FST estimate: 0.0058). As a secondary measure, we independently assembled complete mitochondrial genomes from all individuals and observed no delineation between host or location. The overall lack of detectable population structure at the nuclear and mitochondrial genome levels suggests a large population with flexible dietary preferences and does not show evidence of genetically driven host preference.

  PublisherDOI

• Evaluation of insecticides for management of soybean aphid, 2025

  Arthropod management tests · 2025-01-01

  articleOpen accessSenior author
  PublisherOA PDFDOI

• Legume host range and soybean host plant resistance for soybean tentiform leafminer, <i>Macrosaccus morrisella</i> (Lepidoptera: Gracillariidae)

  Journal of Economic Entomology · 2025-05-19 · 2 citations

  articleSenior author

  The soybean tentiform leafminer, Macrosaccus morrisella (Lepidoptera: Gracillariidae), was known to feed on only two legumes native to North America, and it has recently expanded its host range to soybean, Glycine max (Fabales: Fabaceae). However, the threat to other legume crops and potential for host plant resistance for M. morrisella management in G. max is unknown. Thus, M. morrisella host range among different species of legume crops and genotypes of G. max were evaluated through complementary choice and no-choice experiments. Macrosaccus morrisella oviposited on its native host American hogpeanut (Amphicarpaea bracteata (Fabales: Fabaceae)) and G. max (both grain and vegetable types), but not on Phaseolus vulgaris, Vigna unguiculata, Cicer arietinum, Vicia faba, Pisum sativum, and Lens culinaris (Fabales: Fabaceae). Low oviposition was observed on Vigna radiata and Phaseolus lunatus (Fabales: Fabaceae) in a choice test, but no larvae survived on either legume. When G. max genotypes were compared, lower but detectable oviposition (50 to 100 eggs per plant) was observed on PI229358 and PI227687 in choice and no-choice tests, and lower survival rates (20 to 40%) on PI229358 and M15-105140 in a no-choice test. These results indicate that M. morrisella host range appears to be restricted to the previously known native hosts and G. max, but continued monitoring for adaptation to other legumes and further studies testing multiple populations of M. morrisella are necessary. Furthermore, sources of G. max with lower susceptibility against M. morrisella were identified and could be utilized in G. max breeding programs for the development of host plant resistance for M. morrisella management.

  PublisherDOI

• Synopeas ruficoxum Buhl (Hymenoptera, Platygastridae) is a natural enemy of soybean gall midge, Resseliella maxima Gagné (Diptera, Cecidomyiidae)

  Journal of Hymenoptera Research · 2025-08-25 · 2 citations

  articleOpen access

  Platygastridae (Hymenoptera) is known as a ‘dark taxon’ as it is highly diverse and understudied. Within Platygastridae, one of the largest genera is Synopeas Förster, species of which parasitize Cecidomyiidae (Diptera). This study identifies a new host association between these two families, with Synopeas ruficoxum Buhl as the second reported parasitoid of soybean gall midge, Resseliella maxima Gagné. Parasitoids were reared from soybean stems infested with R. maxima collected in Nebraska, USA. Furthermore, PCR assays confirmed that R. maxima larvae are parasitized by S. ruficoxum in the field. All S. ruficoxum specimens were female, suggesting that this may be an asexually reproducing population. We found that some, but not all, S. ruficoxum were infected with a bacterium, Wolbachia , known to mediate asexual reproduction in other insects, suggesting other factors may be responsible for the all-female population. Publicly available barcoding data allowed us to determine that S. ruficoxum is also present in Eastern Canada, which is beyond the known geographic range of R. maxima . This suggests that S. ruficoxum has other hosts or that the geographic range of R. maxima is broader than currently documented. A redescription and diagnostic data for S. ruficoxum are provided, advancing the ability to use this parasitoid for biological control of R. maxima .

  PublisherOA PDFDOI

• Laboratory rearing methods for the soybean tentiform leafminer (Lepidoptera: Gracillariidae), a new pest of soybean

  The Great Lakes Entomologist · 2024-09-30 · 5 citations

  articleSenior author

  Soybean tentiform leafminer (STL), Macrosaccus morrisella (Fitch) (Lepidoptera: Gracillariidae), is a leaf-mining microlepidopteran native to North America that was recently discovered feeding on soybean, Glycine max (L.) Merr., in Canada and the United States. A laboratory rearing system for STL was developed on live soybean plants. The methods for continuous rearing or cyclic (i.e., generational) production of insects are described herein. All rearing was performed in a walk-in environmental chamber at 25°C (±2°C), with ~70% relative humidity and a photoperiod of 16:8 (L:D). Adults of STL were allowed to oviposit on clean soybean plants in an oviposition cage. Soybean plants with STL eggs were maintained in a separate immature-development cage for a total of ~2.5 weeks, passing through the egg stage (3–4 days), larval development through the serpentine mine stage (4–6 days), blotch mine stage (5–6 days), and tentiform mine stage to adult emergence (7–10 days). Plants in the tentiform mine stage were then trimmed and transferred to a separate cage until adult emergence, typically beginning 19–23 days after egg oviposition. The methods described allowed for the successful rearing of STL, producing a steady supply of STL adults or plants infested with immature STL. The methodology can be modified to fit the needs of various research projects.

  PublisherDOI

• Evaluation of the toxicity of translaminar insecticides against the soybean tentiform leafminer (Lepidoptera: Gracillariidae), a potential new pest of soybean

  Journal of Economic Entomology · 2024-10-25 · 2 citations

  articleOpen accessSenior author

  Macrosaccus morrisella (Fitch) (Lepidoptera: Gracillariidae) is a leaf-mining microlepidopteran native to North America recently reported feeding on soybean in the United States and Canada. Control methods for the management of this pest remain unknown. The insecticides Agri-Mek SC (abamectin) and Endigo ZXC (lambda-cyhalothrin + thiamethoxam) were evaluated for: (i) effects against immature stages of M. morrisella in potted soybean plants; (ii) effects against adults of M. morrisella through different routes of exposure; and (iii) efficacy of field applications against M. morrisella. In the experiment with immature stages, when either insecticide was applied to potted plants with M. morrisella in serpentine or blotch mines, significantly fewer adults emerged compared to the untreated plants. In contrast, adult emergence from potted plants treated with either insecticide when M. morrisella was in tentiform mines did not differ from untreated plants. In the experiment with adults, the survival of M. morrisella exposed to either insecticide through oral exposure or residual contact + oral exposure was significantly lower than that for residual contact exposure alone, which in turn was lower than the untreated control. Within each exposure route, the response to the 2 insecticides did not differ. In the field experiment, at 21 days after insecticide application, the mean percentage of leaf area mined was significantly lower in plots treated with Endigo ZCX compared to plots treated with Agri-Mek SC or those left untreated. These results suggest that Endigo ZXC and to a lesser extent Agri-Mek SC may have potential for management of M. morrisella.

  PublisherOA PDFDOI

• Soybean aphid management and perception of insecticide resistance by farmers

  Journal of Integrated Pest Management · 2024-01-01 · 1 citations

  articleOpen accessSenior author

  Abstract In the Midwest United States, soybean aphids can cause significant economic losses in soybean production. The repeated use of insecticides within the same family has led to the development of insecticide resistance in soybean aphids. Implementing integrated pest management (IPM) and insecticide-resistance management (IRM) strategies can help farmers reduce the frequency of insecticide applications and delay the evolution of soybean aphid resistance while reducing production costs, maintaining yields, and protecting the environment. Farmers play a crucial role in implementing such practices; therefore, to understand farmers’ practices for management of soybean aphids and their perceptions of insecticide resistance, a survey of soybean farmers in Minnesota and North Dakota was conducted in 2021. Overall, the reported decision-making sources were similar for both farmers who changed and those who did not change their aphid management due to insecticide resistance; these were crop consultants and agricultural retailers. The threshold used by farmers in both groups to determine whether to use a foliar insecticide was lower than the research-based threshold for soybean aphids, and farmers were aware that this could contribute to insecticide resistance. In addition, farmers who changed soybean aphid management were more concerned than farmers who did not change about insecticide resistance and were implementing good practices such as scouting, using labeled application rates, and rotating insecticide modes of action. The results of this research can inform the refinement of IPM and IRM programs as well as extension education efforts.

  PublisherDOI

Frequent coauthors

• W. D. Hutchison

  47 shared

• E. C. Burkness

  University of Minnesota

  30 shared

• Paul J. CaraDonna

  Center for Plant Conservation

  28 shared

• Andrea Gruver

  Center for Plant Conservation

  28 shared

• Alexandra Duffy

  University of California, Davis

  28 shared

• Julie Craves

  23 shared

• Adrienne O'brien Treasurer

  Michigan State University

  23 shared

• Mark F. O’Brien

  Alma College

  23 shared

Labs

• Robert Koch LabPI

Awards & honors

• Award of Excellence in Integrated Pest Management (North Cen…
• Distinguished Extension and Outreach Award (CFANS, U of MN)
• Dean's Award for Distinguished Campus-Based Faculty (Extensi…
• IPM Team Award (Plant-Insect Ecosystems Section, ESA)
• Dean's Award for Distinguished Team (Extension, U of MN)