Biological Control of Bacterial Wilt of Potatoes: Attempts to Induce Resistance by Treating Tubers with Bacteria. J. Kempe, Department of Plant Pathology, University of Wisconsin, Madison 53706. L. Sequeira, Department of Plant Pathology, University of Wisconsin, Madison 53706. Plant Dis. 67:499-503. Accepted for publication 22 October 1982. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-499.

Induced resistance and microbial antagonism were investigated as possible methods for control of bacterial wilt of potato caused by Pseudomonas solanacearum. Tuber seed pieces (containing buds) of the tolerant cultivar Ontario were treated by dipping them in suspensions of different bacteria or by introducing the bacteria directly into the bases of the emerging buds. The bacteria tested included avirulent (B82) and incompatible (70) strains of P. solanacearum, proteolytic (W163) and pectolytic (WP95) strains of P. fluorescens, and strains of P. syringae pv. glycinea (S-9-4) and pv. lachrymans (PHW214-6). Plants grown from treated tubers were challenged when 20–30 cm tall by stem or root inoculation with the highly virulent strain 276 of P. solanacearum. Treatment with the P. solanacearum and P. fluorescens strains caused a significant reduction in disease severity, particularly when plants were challenged by stem inoculation at relatively low inoculum levels and/or disease progress was slow in the control plants. When plants were challenged by root inoculation, there was a significant decrease in disease severity in treated plants when the roots were left intact but not when roots were injured. There was no correlation between effectiveness of tuber treatment with different bacterial strains and their ability to inhibit growth of P. solanacearum in vitro.

Keyword(s): acquired resistance, potato brown rot, Solanum tuberosum.