Seed bio-priming with Serratia plymuthica HRO-C48 for the control of Verticillium longisporum and Phoma lingam in Brassica napus L. spp. oleifera

Sammanfattning: Oilseed rape is one of the most important crops all over the world. It is susceptible to many fungal pathogens including soil-borne Verticillium longisporum (causes Verticillium wilt) and Phoma lingam (causes blackleg). Available control measures are not sufficient to control these diseases. One way to increase both quality and quantity of crop yield is by treating seeds with beneficial microorganisms before sowing. Effect of seed bio-priming with the antagonistic bacterium, Serratia plymuthica HRO-C48 was investigated in oilseed rape (Brassica napus L. spp. oleifera) against wilt and black leg. Rifampicin-resistant strain of the bacterium was used in this study. The effect on wilt was assessed in cultivars Visby, Trabant, KWS 63 and KWS 136 in growth chamber experiments while the effect on black leg was observed in presence and absence of fungicides (Folicur © or Caramba ©) in Visby cultivar the field trials on-going at Birkenmoor and Hohenlienth in Germany. V. longisporum was artificially inoculated and Phoma infection in the field trail was naturally occurring. Disease severity and plant recorded in plants with V. longisporum were compared with that in presence of S. plymuthica HRO-C48rif . In field experiments, leaf infestation frequency and number of leaf pycnidia due to Phoma were compared between the treatments. Bacterial population of inoculated S. plymuthica HRO-C48rif was also estimated in the rhizospheres of both growth chamber and field experiments. Summarised results showed that S. plymuthica HRO-C48rif was able to colonise the rhizospheres of oilseed rape in both growth chamber and field trails but it was not able to reduce the infections by V. longisporum or Phoma lingam in a satisfactory way. Furthermore, the application of bacterium seemed compatible with the fungicides and the bacterial populations declined below the detection level.