Farm Table says:
Potato (Solanum tuberosum L.) growers face many challenges from seed- and soilborne pathogens, including reduced plant growth and vigor, as well as losses in tuber quality and total and marketable yield. In this study, we evaluated three different disease management approaches, compost amendment, biocontrol organisms, and a disease-suppressive rotation, for their individual and combined effects on soilborne diseases, as well as total and marketable tuber yield.
Integrating multiple soils and disease management practices may improve crop productivity and disease control, but potential interactions and limitations need to be determined.
The main objectives of the work reported here were to evaluate a rapeseed green manure rotation, a conifer-based compost amendment and biocontrol organisms for their:
- Individual and combined treatment effects on soilborne diseases of potato.
- Individual and combined treatment effects on total and marketable yield of tubers.
- Whether these effects differed at an organically managed potato production site compared with a conventional potato production site.
This research is part of a larger project, in which these management practices were also assessed for their effects on soil physical and chemical properties (Erich et al., unpublished data), insect pests and soil microbial community characteristics.
Three different potential disease-suppressive management practices, including a Brassica napus (rapeseed) green manure rotation crop, conifer-based compost amendment, and three biological control organisms (Trichoderma virens, Bacillus subtilis, and Rhizoctonia solani hypovirulent isolate Rhs1A1) were evaluated alone and in combination at sites with both organic and conventional management histories for their effects on soilborne diseases and tuber yield.
Rapeseed rotation reduced all observed soilborne diseases (stem canker, black scurf, common scab, and silver scurf) by 10 to 52 % in at least one year at both sites. Compost amendment had variable effects on tuber diseases, but consistently increased yield (by 9 to 15 %) at both sites. Biocontrol effects on disease varied, though Rhs1A1 decreased black scurf at the conventional site and T. virens reduced multiple diseases at the organic site in at least one year. Combining rapeseed rotation with compost amendment both reduced disease and increased yield, whereas biocontrol additions produced only marginal additive effects.
Use of these treatments alone, and in combination, can be effective at reducing disease and increasing yield under both conventional and organic production practices.