Recent Graduates

Graduate Program

Max Aleman

Ph.D., Plant Pathology and Environmental Microbiology

Aleman's thesis is titled "Disease Impact on Aerial Surface Microbiomes and Chemistry."

Aleman’s work integrated microbiome ecology, metabolomics, and plant-microbe interactions. His dissertation explored how microbial communities and surface metabolites influence disease outcomes in agricultural systems. He led three major projects: Mushroom Microbiome Dynamics — analyzing how bacterial blotch symptoms alter microbial composition in Agaricusbisporus using metagenomics. Tomato Leaf Metabolomics — identifying defense-related metabolite shifts in response to Pseudomonas syringae infection and hormone signaling. Systemic Induced Susceptibility — linking pathogen-altered surface metabolites to bacterial fitness and disease progression in distal tomato tissues. Throughout, he used molecular biology, high-throughput sequencing, and analytical chemistry to investigate host-microbe-environment interactions. He also contributed to collaborative projects, taught undergraduates in both lab and lecture settings, and mentored students on molecular techniques and experimental design. His training at Penn State was defined by interdisciplinary approaches to biological questions, a commitment to research with real-world implications, and a deep investment in both scientific rigor and mentorship.

When asked about insight for prospective students, Aleman responded, "Rest is part of the work. You don’t have to earn your humanity by burning yourself out. There’s room in science for gentleness, vulnerability, and difference. You don’t have to harden yourself to succeed. You can be both critical and kind — to yourself, to others, and to the system you’re navigating. Your questions don’t have to be perfect to be powerful. What matters is the curiosity and care you bring to asking them.”

Aleman received the following awards during his graduate career at Penn State:

• Northeast SARE Graduate Student Award
• NSF Graduate Research Fellowship Program

Johanny Castro

Ph.D., Plant Pathology

Johanny Castro has accepted a position as a Professor of Plant Pathology at the University of Costa Rica.

Castro's thesis is titled "An Integrated Study of Postharvest Apple Fruit Decay Pathogens in the Mid-Atlantic Region of the United States."

During his time at Penn State, he worked on multiple research projects that focused on studying postharvest apple diseases. He visited multiple apple orchards and packinghouses in the Mid-Atlantic, and collected samples to identify the main pathogens causing decay. He collected samples from multiple sources of spores of postharvest apple decay pathogens in order to help apple growers prioritize management practices of postharvest apple decay. He also studied fungicide sensitivity for postharvest apple decay pathogens and evaluated alternatives to synthetic fungicides with the objective of providing apple growers with environmentally-friendly alternatives for postharvest apple decay management. He attended multiple scientific meetings and Extension activities in which he presented the main results obtained to a broad audience that included apple growers, students, and scholars.

When asked about insight for prospective students, Castro responded, "Define very carefully your academic and personal objectives at the start of your Ph.D. Based on this, search constantly for opportunities that complement your education at Penn State. Put always your mental health first, without forgetting that in order to grow, a certain level of discomfort is usually necessary."

Johanny Castro received the following awards during his graduate career at Penn State:

• Evans Family Award for Graduate Extension Achievement
• Penn State Extension Graduate Scholarship in honor of Dr. John S. Shenk and Dr. J.D. Harrington

Cameron Mehalek 

M.S., Plant Pathology

Cameron Mehalek has accepted a position as an Extension Educator in Horticulture and Agriculture for the University of Georgia.

Mehalek's thesis is titled "Southern Blight: A New Threat to Pennsylvania Apple Growers."

Mehalek studied a soilborne pathogen called southern blight (caused by Sclerotium rolfsii or Sclerotium delphinii). The disease was observed in 2018 on apple in Adams County, Pennsylvania, which accounts for over 70% of Pennsylvania’s apple production. Since its emergence, southern blight has been a persistent challenge to apple growers in the region, with the lack of research on the host-pathogen combination severely limiting the control options at their disposal. The goal of his research was to provide the information necessary for apple growers to effectively manage the disease. Starting in the summer of 2023, he sampled orchards throughout Adams County in order to analyze the environmental conditions facilitating southern blight in Adams County, including temperature, pH, and rainfall. Additionally, they evaluated the susceptibility of commonly used apple rootstocks to the pathogen using potted trees in a greenhouse. Lastly, he assessed the efficacy of active ingredients from commercial fungicides against the fungus since no products are currently labeled for legal soil application for the treatment of southern blight on apple.

When asked about insight for prospective students, Mehalek responded, "You don't have to have it all figured out - you just have to keep going."

Ram Neupane

Ph.D., Plant Pathology; International Ag

Ram Neupane has accepted a position as a Research Associate at Michigan State University.

Ram Neupane's thesis is titled "Exploring Diversity, Pathogenicity, and Copper Tolerance of Bacteria Associated with Symptomatic Onions in Pennsylvania and New York."

His dissertation explored bacterial diversity associated with symptomatic onions in PA and NY, their pathogenicity and copper tolerance. A key finding of the dissertation was that Pantoea and Burkholderia were determined to be the most prevalent pathogens in both states, and the copper tolerance in Burkholderia was found to be higher. More than 90% of the isolates tested in in vitro plate assay were identified to be tolerant at 200 ppm of copper sulphate pentahydrate).

When asked about insight for prospective students, Neupane responded, "Penn State offers a wealth of resources to support your academic and professional growth—but remember, you are ultimately in charge of your project. Your PI is there to guide and support you, but it’s up to you to take initiative. Don’t just go to your advisor with problems—go with ideas for possible solutions. This approach not only helps you move your research forward but also demonstrates critical thinking and ownership. At the same time, don’t get overly fixated on just your research. Graduate school is also a time for exploration and professional development. Take advantage of opportunities beyond the lab—get involved in student organizations, volunteer at events like Ag Progress Days, or participate in science policy forums. These experiences broaden your perspective, build your network, and can help shape your future career in meaningful ways. Don’t just chase data—chase growth.

Ram Neupane received the following awards during his graduate career at Penn State:

• 2024-25 Vice Provost and Dean of the Graduate School Student Persistence Scholarship *AIARD Future Leaders Fellowship
•  Harold K. Schilling Dean’s Graduate Scholarship
• Growmark Inc. Graduate Scholarship
• Lester P. Nichols Memorial Award
• L. Earl and Veronica Casida Graduate Scholarship
•  Ardeth and Frisbey International Student Award

Sadie Seamen

M.S., Plant Pathology

Sadie Seamen's thesis is titled "Bad Neighbors: A Meta-genomics Approach to Potato Disease Diagnostics."

 Potatoes (Solanum tuberosum) are the seventh most produced crop and highest-ranking non-grain crop produced globally, with the United States ranking as the fourth highest producer. As a staple food source, potatoes provide essential nutrients, such as vitamin C, vitamin B6, potassium, and iron, contributing to the food security of millions of people. However, projections estimate increased incidences of disease in many food crops, posing a potential threat to global and local potato production. In the United States, some diseases widespread throughout potato cultivation regions are soft rot and blackleg, caused by pathogenic Pectobacterium and Dickeya species, and Verticillium wilt, caused by Verticillium dahliae. Crop yield losses in potato fields caused by Pectobacterium species range from 15-30% depending on field conditions, while losses caused by V. dahliae can reach 20-30%. Since 2014, outbreaks of soft rot and blackleg have been reported across the U.S. and continue to be a disease management challenge for today’s growers. Verticillium wilt disease incidence is even more widespread compared to soft rot, with the pathogen found in all U.S. potato-growing regions. To combat the spread of these diseases, ongoing research focuses on host resistance, the potential roles that microbes have in plant resistance, and characterizing the genomes of potato pathogens present in symptomatic potato fields. These studies emphasize the importance of understanding and exploring the pathogen ecology and host-associated microbiomes. To investigate the disease ecology of soft rot and Verticillium wilt, shifts in the potato microbiome are described with approaches such as metagenomics and whole genome sequencing. By using these tools, she will analyze shifts in the potato microbiome when infected with soft rot pathogenic Pectobacterium or Verticillium dahliae and further described the genomes of Pectobacterium species that are present in symptomatic potato samples. The objectives of her study were: (1) Describe and compare the microbiome composition of mock inoculated potato stems and stems inoculated with either Pectobacterium parmentieri or Verticillium dahliae, (2) characterize the genome of Pectobacterium species isolated from symptomatic tissues, (3) develop a publicly available workflow for introductory level users that describes the process of DNA extraction and whole genome sequencing for Gram-negative bacteria. Throughout her last semester, she was a TA for Veronica's microbiome analysis class PPEM440. Additionally, she is currently working on a manuscript in collaboration with the Pennsylvania Department of Agriculture Plant Pathology unit where she is assessing the genomes of Pectobacterium isolates collected from 1992 to 2003 and comparing them to the isolates she assessed for her thesis that were collected in 2016.

When asked about insight for prospective students, Seamen responded, "Please ask for help when you feel you need it! Do not be afraid to say you have made a mistake, need more time, or are struggling. Your advisor is here for you and should meet you where you are in your academic journey. Be your best advocate and you will go far!

Sadie Seamen received the following awards during her graduate career at Penn State:

• Watt's Endowment Fund
• Fund for Excellence in Graduate Recruitment (FEGR) Assistantship
• Graham Scholarship

Leadership Roles: 

Social chair of PPA 2024-2025

Jamie Priska Spychalla 

Ph.D., Plant Pathology

Jamie Priska Spychalla's thesis is titled "Bridging Spatial Scales: Microbial Dynamics in Grape Cluster Rots Across the United States."

The goal of her work at Penn State was to untangle biological aspects of the sour rot disease complex using microbial ecology research methods. She had in field experiments at different spatial scales spanning from vineyards across the United States to the individual plant host. The different spatial scales explored in her dissertation, coupled with the investigation of both taxonomic and functional components of microbial communities in response to environmental factors (e.g., meteorologic conditions, fungicide stress), help us better understand the drivers and basic biological hallmarks of the late season grape cluster rots, including the sour rot disease complex.

Jamie Priska Spychalla received the following awards during her graduate career at Penn State:

• NSF GRFP
• One Health Microbiome - Qiagen internship