Use of biocontrol organisms and compost amendments for improved control of soilborne diseases and increased potato production

Authors: Larkin, Robert - Bob; TAVANTZIS, STELLOS - University Of Maine

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2013
Publication Date: 2/14/2013
Citation: Larkin, R.P., Tavantzis, S. 2013. Use of biocontrol organisms and compost amendments for improved control of soilborne diseases and increased potato production. American Journal of Potato Research. 90:261-270.

Interpretive Summary: Potato growers face many challenges from soilborne diseases, including reduced plant growth and vigor, and losses in tuber quality and yield. In this research, nonpathogenic microbial biocontrol organisms and compost amendments were evaluated, alone and in combination, as alternative or supplemental disease management practices in potato production over three field seasons in Maine. All biocontrol treatments reduced multiple different soilborne potato diseases (stem canker, black scurf, and common scab) by as much as 30-58% compared to nontreated plants, and the combination of two different biocontrol treatments provided slightly better overall results than the individual treatments. All compost amendments increased tuber yield substantially, by 11-51%, over multiple years of trials. However, compost amendments did not reduce soilborne disease, and for one disease, may have increased disease levels. The combination of biocontrol and compost in a single treatment provided some benefits from both individual treatments, such as increased yield (from compost) and some disease reduction (from biocontrol), but was not significantly better than each individual treatment. This research demonstrated the usefulness of these approaches and combinations as additional options for reduction of soilborne diseases and increased tuber yield in potato production. This research is useful for scientists, extension personnel, and growers, providing practical information on the use of supplemental management practices for enhanced sustainability and productivity in potato production systems.

Technical Abstract: Soilborne potato diseases are persistent problems in potato production and alternative management practices are needed. In this research, biocontrol agents (Bacillus subtilis GB03 and Rhizoctonia solani hypovirulent isolate Rhs1A1) and compost amendments (from different source material), were evaluated alone and in combination, for their potential to reduce soilborne diseases and increase tuber yield over three field seasons in Maine. Both biocontrol organisms reduced multiple soilborne diseases, stem and stolon canker by 20-38%, black scurf by 30-58%, and common scab by 10-34% relative to the nontreated control treatment, and the combination treatment of both biocontrol organisms together provided nominally better control than individual treatments. However, biocontrol treatments had no direct effect on tuber yield. Compost amendments from different sources all increased total and marketable tuber yield substantially (11-37% and 17-51%, respectively) relative to nontreated controls. However, except for some reduction of Rhizoctonia canker, compost amendments did not reduce soilborne diseases (black scurf and commons scab) in any year, and resulted in increased levels of common scab in some years. The combination compost-biocontrol treatment, although did not perform significantly better than individual component treatments, still provided indications of combined beneficial effects from both component treatments. This research demonstrated the usefulness of these approaches and combinations as additional options for reduction of soilborne diseases and increased tuber yield and can be implemented for enhanced sustainability and productivity in potato production systems.