Fungicide seed coating decreased rhizobia survival and nodulation of field pea

Authors: Judith Rathjen¹, Maarten Ryder¹, Thang Viet Lai¹, Matthew Denton¹

¹University of Adelaide, Waite Campus, Urrbrae

Funded by: GRDC project 9176500. Increasing the effectiveness of nitrogen fixation in pulse crops through development of improved rhizobial strains, inoculation and crop management practices.

Peer review:

Key Words: field pea, rhizobia, nodulation, nodules, n fixation, fungicide seed coating

Key Messages

• Nodulation was reduced when pea seeds were coated with P-Pickel T fungicide before inoculation
• Reductions in rhizobia numbers on fungicide-coated seeds occurred very quickly, within 2 h, but the toxic effect of the fungicide continued after sowing
• Dry soil conditions at sowing in 2018 are likely to have exacerbated fungicide toxicity to the rhizobia