|Manmathan, Harish - UNIVERSITY OF MAINE|
|Tavantzis, Stellos - UNIVERSITY OF MAINE|
Submitted to: Northeast Potato Technology Forum Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: March 1, 2007
Publication Date: March 14, 2007
Citation: Larkin, R.P., Manmathan, H., Tavantzis, S. 2007. Effects of Compost and Biocontrol Amendments on Soilborne Diseases of Potato. Northeast Potato Technology Forum Abstracts. CD-ROM. Technical Abstract: Two composts and two biological control agents were evaluated alone and in combination for their effects on the development of soilborne diseases of potato. The experiment was conducted on field research plots in Newport, ME. The compost amendments consisted of commercially available compost blends, with one being a conifer-based compost made from hemlock bark, and the other being a hardwood-based compost made from aspen. Biocontrol treatments consisted of the bacterial biocontrol agent Bacillus subtilis GB03 (Bsub), and a hypovirulent strain of R. solani, HV-Rs (Bandy and Tavantzis, 1990, Am. Potato J. 67: 189-199). All treatments significantly reduced stem canker relative to the nontreated control, by 27 to 50%. The biocontrol treatments, Bsub, HV-Rs, and their combination, reduced the incidence and severity of black scurf by 23-66%. Conifer compost + HV-Rs, but not the hardwood compost combination, reduced the incidence and severity of black scurf by 34-55%. Common scab was reduced by Bsub, but increased by hardwood compost (due to increase in erumpent-type lesions). Total tuber weight was significantly greater with the conifer compost treatment, and marketable weight was greater for all compost treatments and combinations, averaging 30 to 54% greater than the nontreated control. These results indicate that B. subtilis, HV-Rs, and conifer compost can reduce soilborne diseases of potato, and that combinations of these treatments can reduce disease and improve yield.