Understanding Emergence of Vegetable Vascular Wilt Disease from an Ecological Perspective

Project Overview

Project Type: Graduate Student
Funds awarded in 2020: $14,930.00
Projected End Date: 12/31/2023
Grant Recipient: The Pennsylvania State University
Region: Northeast
State: Pennsylvania
Graduate Student:
Faculty Advisor:
Dr. David Geiser
The Pennsylvania State University


  • Vegetables: tomatoes


  • Production Systems: agroecosystems
  • Soil Management: soil microbiology

    Proposal abstract:

    Emerging fungal plant diseases such as Fusarium wilt of tomato cause significant losses for growers in the northeast United States. Although some members of the Fusarium oxysporum Species Complex (FOSC) are responsible for this plant disease on over 100 crops, most isolates live in the soil or inhabit plants without causing disease. In fact, because of the complex evolutionary history of this group and the multiple modes of genetic exchange available, the isolates that cause Fusarium wilt can be very closely related to isolates that do not. As these isolates occupy the same ecological niche in agroecosystems, it is important to understand how these isolates relate to and impact one another. Improving this understanding helps researchers understand risks related to pathogen emergence and aid in developing better diagnostic tools. Therefore, it is crucial that we understand the evolutionary and ecological context from which pathogenicity emerges. This necessitates characterizing host adaptation among nonpathogenic isolates. Therefore, we propose to conduct a systematic sampling of FOSC isolated from specific parts of asymptomatic tomato plants and agricultural and non-agricultural soil. This sampling will allow meaningful comparisons to evaluate the genetic diversity of nonpathogenic FOSC in Pennsylvania tomato production, and identify factors that may be influencing population structure, and adaptation to tomato. Specifically, we will assess 1. Agricultural production, 2. Crop history, 3. Time, and 4. Host Variety. We will also assess current diagnostic approaches for Fusarium-associated diseases. We will identify educational needs of diagnosticians for Fusarium identification and provide resources to address those needs.

    Project objectives from proposal:

    We seek to characterize nonpathogenic F. oxysporum occupying the same ecological niche as pathogenic isolates to better understand host adaptation and genetic exchange within the species complex.

    Objective 1: Determine if F. oxysporum soil population is impacted by agricultural production.

    Objective 2: Determine if F. oxysporum soil population is shaped by the agricultural history of the field, specifically, the crops grown in the field.

    Objective 3: Determine if F. oxysporum soil population changes over the course of the growing season.

    Objective 4: Determine if Fusarium wilt resistance genes impact the F. oxysporum populations asymptomatically colonizing tomato.

    Objective 5: Identify current practices in Fusarium identification in plant diagnostic clinics and identify educational needs among diagnosticians.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.