The soybean cyst nematode (SCN; Heterodera glycines) is the most economically consequential pathogen of soybeans worldwide. Although biological control of SCN was proposed decades ago, only a few products are available on the market. Mining for new fungal biological control organisms and evaluating their potential to enhance integrated management of SCN is crucial. In this study, we evaluated 20 candidate biological control organisms in vivo that were selected out of a culturable mycobiome of over 5000 isolates based on their performance in in vitro assays. Of these isolates, labelled A through T, we identified three isolates, one Ilyonectria sp. (D), and two Purpureocillium sp. isolates (E and T), that significantly reduced SCN reproduction on a susceptible soybean variety (Sturdy) inoculated with both high and low levels of SCN eggs, compared to an untreated control, in a growth chamber cone-tainer assay. In a greenhouse pot assay, Purpureocillium isolates E and T also controlled nematode reproduction better than an untreated control and performed on par with the commercial fungal biological control agent, MeloCon® WG, which was applied at 41-fold higher concentration. In a second greenhouse assay, with higher nematode numbers, only isolate E performed as well as MeloCon® WG. This research identified promising candidate biological control agents of SCN that are as or more effective than existing products at much lower spore inoculation levels.
Bibliographical noteFunding Information:
We acknowledge funding from USDA grant number NIFA2015-67031-23419 and the Minnesota Soybean Research and Production Council . We sincerely thank the nematology laboratory technicians Ms. Cathy Johnson, Mr. Wayne Gottschalk, Ms. Basia Eldhom, Mr. Bill Fitzpatrick and Mr. Michael Schickling for their support in processing all the soil samples. We also thank Ms. Pamela Warnke and Mr. Douglas Brinkman, managers of the University’s plant growth facilities, for providing all help and support to run this study.
© 2021 The Authors
- Biological control
- Growth chamber
- Heterodera glycines
- In planta assays
- Soybean cyst nematode