Use and effects of different Brassica and other rotation crops on soilborne diseases and tuber yield of potato

Authors: Larkin, Robert - Bob; LYNCH, R - University Of Maine

Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2018
Publication Date: 10/30/2018
Citation: Larkin, R.P., Lynch, R.P. 2018. Use and effects of different Brassica and other rotation crops on soilborne diseases and tuber yield of potato. Acta Horticulturae. 4:37.

Interpretive Summary: Soilborne diseases are persistent problems in potato production, resulting in reductions in tuber quality and yield, and current management of these disease has not been sustainable or sufficiently effective. Crop plants in the Brassica (Mustard) family have been reported to reduce soilborne potato diseases, but the best ways to utilize these plants as rotation crops for control of diseases in potato production systems has not been established. In this research, two 2-year crop rotations were established at three different sites with histories of soilborne diseases, and up to six different Brassica crops (canola, winter rapeseed, yellow and brown condiment mustards, oriental mustard, oilseed radish, and a mustard blend) and standard rotation crops (ryegrass, buckwheat) were evaluated as rotation and green manure crops. Rotation crop treatments, including Brassica and non-Brassica crops, reduced multiple soilborne diseases at all sites, but results were variable from site to site and year to year, with different crops performing better at different sites and years. Overall, ryegrass cover crops and mustard blend green manures provided the most consistent reductions of soilborne diseases. Although both Brassica and non-Brassica rotations offered potential for disease reduction in potato cropping systems, no single rotation crop performed consistently better than several others. This research is useful for scientists, extension personnel, consumers, and particularly potato growers, providing information on the development of better, more sustainable disease management and improved cropping systems for potato production systems.

Technical Abstract: Soilborne diseases are persistent problems in potato production, resulting in reductions in tuber quality and yield. Brassica rotation crops have been reported to reduce soilborne potato diseases, but how to best utilize Brassicas in potato production systems has not been established. In this research, two 2-year crop rotations were established at three different sites with histories of soilborne diseases, and up to six different Brassica crops (canola, winter rapeseed, yellow and brown condiment mustards, oriental mustard, oilseed radish, and a mustard blend) and standard rotation crops (ryegrass, buckwheat) were evaluated as rotation and green manure crops. Rotation crop treatments affected incidence and severity of soilborne diseases at all sites. However, results were variable from site to site and year to year. Perennial ryegrass and mustard blend rotations reduced powdery scab disease where it occurred by 31-55% relative to other rotations. The mustard blend, ryegrass, and other Brassica rotations also reduced common scab, silver scurf, and black scurf at various sites, but not consistently at all sites. At one site, the mustard blend and a barley/ryegrass rotation reduced black scurf (by 21- 58%) and common scab (by 13-34%) relative to no rotation. Overall, disease control was not correlated with biofumigation potential or rotation crop biomass production. Although both Brassica and non-Brassica rotations offered potential for disease reduction in potato cropping systems, no single rotation crop performed consistently better than several others. Also, fall plantings of Brassica cover crops were not successful and may not be practical in short growing season regions.