2021
Evaluation of aggressiveness among Diaporthe species isolated from Mid-Atlantic Soybeans
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Contributor/Checkoff:
Delaware Soybean Board
Category:
Sustainable Production
Keywords:
Crop protectionDiseaseField management
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Alyssa Koehler, University of Delaware
Co-Principal Investigators:
Project Code:
PLSC43292521008/PLSCDA2108
Contributing Organization (Checkoff):
Delaware Soybean Board
$5,989
Institution Funded:
University of Delaware
$5,989
Brief Project Summary:

Fungal pathogens can be very damaging to soybean production, reducing both yield and quality. A previous survey documented common soilborne pathogens across the region. It identified various diseases caused by the Phomopsis/Diaporthe complex in over 60% of the surveyed fields. Host resistance is available to certain Diaporthe species. Through greenhouse screening and inoculated studies, this project seeks to characterize observed species to improve management recommendations. That includes assessing the aggressiveness of Diaporthe isolates from Mid-Atlantic soybean field, estimating potential yield effects of Mid-Atlantic Diaporthe isolates, sharing research findings through extension events and using findings to inform future management trials.

Key Benefactors:
farmers, agronomists, Extension agents

Information And Results
Project Deliverables

Findings from this project will be shared through the University of Delaware’s Weekly Crop Update, which reaches over 700 growers, consultants, and stakeholders and provides a platform to discuss disease concerns and other production issues. Data will also be shared through training events and extension presentations such as Mid Atlantic Crop School, and the 2021 Delaware Ag week. Little is known about resistance to various Diaporthe species in currently available soybean cultivars. Improved understanding of variation in local isolate aggressiveness will inform viability of research to investigate resistance as a viable management option and if yield losses are significant enough to merit additional projects to expand the limited management options currently available.

Final Project Results

Updated January 3, 2022:

View uploaded report Word file

View uploaded report 2 PDF file

Soilborne pathogens can reduce soybean yield and quality. Field sites across DE and MD were surveyed during 2019-2020 where multiple species of the Diaporthe/Phomopsis disease complex were identified. Diaporthe longicolla was the dominant pathogen, but D. ueckerae and D. aspalathi were also collected. Little is known on the differences in relative aggressiveness or yield impacts among these species. Project objectives included: 1) Assess the aggressiveness of Diaporthe isolates collected from Mid-Atlantic soybean fields. 2) Estimate potential yield effects of Mid-Atlantic Diaporthe isolates. 3) Share research findings through extension events and use findings to inform future management trials. In this trial, D. longicolla was shown to have the highest disease severity on all varieties screened. The newly identified D. ueckerae had higher disease severity than D. aspalathi in two of the varieties screened. These findings highlight the importance of continuing to understand pathogen dynamics and distribution of Diaporthe species to inform management decisions.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.