Khalil I. Al-Mughrabi
Partner: Potatoes New Brunswick
Abstract: Dry rot caused by various Fusarium species is a disease of significant importance in potato (Solanum tuberosum L.) tubers.
For the first time, two field trials were conducted in 2005 and 2006 in New Brunswick, to assess the efficacy of Pseudomonas fluorescens and
Enterobacter cloacae as seed treatments in suppressing Fusarium dry rot of potatoes (cv. Russet Burbank). The 2005 trial included the
following treatments: 1) non-treated, non-inoculated control; 2) non-treated control inoculated with Fusarium sambucinum; 3) seed inoculated
with F. sambucinum and treated with P. fluorescens; 4) seed inoculated with F. sambucinum and treated with E. cloacae; and
5) seed inoculated with F. sambucinum and treated with the fungicide fludioxonil. A mustard meal treatment was added in the 2006 trial. After harvest,
dry rot and other tuber diseases including silver scurf (Helminthosporium solani) and common scab (Streptomyces scabiei) were assessed. Tubers
were also sized and weighed. Dry rot severity was significantly lower in all treatments when compared to that of the non-treated control inoculated
with F. sambucinum. Fludioxonil reduced dry rot by 55.7% averaged over the two years. This is followed by mustard meal (47.5% reduction in 2006
only); Pseudomonas fluorescens (35% reduction); and Enterobacter cloacae (26.5% reduction). All treatments significantly reduced the severity
of common scab and silver scurf compared to the non-treated, non-inoculated control. Both total and marketable tuber yields were significantly
higher in the E. cloacae treatment compared to the non-treated, inoculated control. Results suggest that, along with fludioxonil, P. fluorescens,
E. cloacae and mustard meal are viable options for managing potato tuber diseases.