Abstract Detail

Host/Plant Pathogen Interactions and Plant Health Management

Trueman, Cheryl [1], Loewen, Steve [1], Goodwin, Paul H. [2].

Acibenzolar-S-methyl and uniconazole effects on bacterial spot and bacterial speck and processing tomato yield.

Tomato field trials were conducted 2011-2013 in Ridgetown, Ontario, Canada, to evaluate foliar applications of the plant defense activator acibenzolar-S-methyl (ASM; Actigard®) and growth regulator uniconazole (UNI; Sumagic®) for management of bacterial speck (Pseudomonas syringae pv. tomato) and spot (Xanthomonas gardneri). UNI applied once at the two-leaf stage (pre-transplanting) was compared to six ASM applications beginning with approximately six-week old, six-leaf stage plants (post-transplanting), UNI+ASM and a nontreated control on ‘TSH4’. Early season area under the disease progress curve (ES-AUDPC) was 31-65% lower in all years, and 42 and 50% lower in 2012 and 2013 for ASM and ASM+UNI versus the control. UNI and ASM increased red fruit yield by 21 to 27% in 2011 and 2013. UNI applied once pre-transplanting, three ASM applications pre-transplanting and UNI+ASM was also compared to three applications of copper hydroxide (CuOH; Kocide 2000®) pre-transplanting, CuOH+UNI, and a nontreated control in ‘TSH4’ and ‘H9909’. ASM+UNI reduced ES-AUDPC by 51-57% versus the control and treatments including CuOH for ‘TSH4’ in 2012. ASM suppressed defoliation by 23% in ‘TSH4’ but increased defoliation by 13% in ‘H9909’ compared to the control in 2012. ASM and ASM+UNI increased red fruit yield for ‘TSH4’ by 29% versus the control and CuOH+UNI, but it reduced total yield by 24% versus the control, CuOH, and CuOH+UNI in ‘H9909’ in 2012. UNI (pre-transplanting) and ASM (post-transplanting) may be beneficial for disease management and yield in some environments, but ASM (pre-transplanting) can have positive or negative effects depending upon the environment and host genotype.

1 - University of Guelph, Ridgetown Campus, 120 Main Street East, Ridgetown, ON, N0P 2C0, Canada
2 - University of Guelph, School of Environmental Sciences, Guelph, ON, N1G 2W1, Canada

Keywords:
Xanthomonas gardneri
Pseudomonas syringae pv. tomato
tomato
bacterial disease
acibenzolar-s-methyl
uniconazole.

Presentation Type: Oral Paper:Papers for Topics
Session: 65
Location: Salon 9/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 11:15 AM
Number: 65005
Abstract ID:371
Candidate for Awards:None