EFFECTIVENESS OF VAPAM (METAM SODIUM) AT

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1 EFFECTIVENESS OF VAPAM (METAM SODIUM) AT REDUCING ROOT ROT SYMPTOMS AND IMPROVING YIELD IN ONTARIO PROCESSING TOMATOES Cheryl Trueman, M.Sc., Ridgetown Campus, University of Guelph, Ridgetown, Ontario, Canada Ken Conn, Ph.D., Agriculture and Agri-food Canada, London, Ontario, Canada

2 -Early decline of tomato foliage, premature defoliation -Root rot: symptoms included banded lesions to severe root rot where we were able to pull the outer root layer (cortex) from the core (stele) J. LeBoeuf -Poor yields in fields with a history of good or excellent production J. LeBoeuf J. LeBoeuf J. LeBoeuf

3 WHAT MAY BE CAUSING VINE DECLINE? 2009 & 2010 Symptoms were noted and samples were sent to Dr. Jim Traquair, AAFC-London A number of pathogens detected: Fusarium spp. (root rot) Colletotrichum coccodes (anthracnose, black dot) Pyrenochaeta lycopersici (corky root rot) Pyrenochaeta terrestris (pink root in onion, red root in corn) Rhizopycnus vagum (melon decline) Pathogens appear widespread

4 WHAT CAN WE DO ABOUT VINE DECLINE? Growers requested we determine if current fumigation practices could help reduce symptoms of root rot symptoms and vine decline Conducted assessments using Vapam HL (42% metam sodium) Telone was not used because it is being withdrawn from the market by the registrant in Canada Vapam currently used in some growing areas on a regular basis

5 OUR APPROACH To determine if Vapam is an effective tool at reducing root rot symptoms and foliar vine decline, and improving tomato yield: 1. Greenhouse pot trials with infested soil 2. Outdoor microplot trials with infested soil 3. Small plot trials in a commercial field 4. Strip trial in a commercial field

6 GREENHOUSE TRIAL Application method for Vapam: Vapam was applied to soil in a double-lined plastic bag and left sealed for 3 days. Rates were equivalent to 696 L/Ha (high) or 348 L/Ha (low) based on the assumption that one square metre of soil has 200 kg of soil to a depth of 15cm. Tomato seedlings were transplanted into infested soil Trial 1: Soil from one site in Essex Co. Root colour, root decay, # lesions & lesion type, dry root wt. Trial 2: Soil from three sites in Essex and Kent Co. # lesions & lesion type, fresh and dry root wt., fresh and dry foliar wt, plant ht.

7 GREENHOUSE TRIAL 1 Treatment A.I. Rate Timing Control Vapam - High Metam sodium 0.36 ml/kg soil 15 DBT Oilseed Radish Isothiocyanates 13 g/pot 15 DBT Rye - 13 g/pot 15 DBT Serenade Max Bacillus subtilis QST g/pot, in 3 ml water Rootshield Trichoderma harzianum KRL-AG2 4 DBT + 7 DAT (drench) 120 g/l 4 DBT (drench) Actigard Acibenzolar-S-methyl 87.5 mg/l 4 DBT + 7 DAT (drench) Quadris azoxystrobin 0.46 ml/l 4 DBT + 7 DAT (drench)

8 Figure 1. Number of lesions per gram of dry root on tomato roots grown in infested soil under greenhouse conditions and treated with various materials for management of vine decline symptoms, Ridgetown, 35 DAT, Trial a 100 Lesions / g of root a a a cd d bc d cd d c c c c c c ab bc bc bcd ab bc bc bcd ab bc bcd bcd b b b b Other Tip Banded Total

9 Figure 2. Dry root weight of tomatoes grown in infested soil under greenhouse conditions and treated with various materials for management of vine decline symptoms, Ridgetown, 35 DAT, Trial a ab a Dry Root Weight (g) c bc c c c 0.2 0

10 Nontreated Oilseed Radish Vapam

11 GREENHOUSE TRIAL2 Three soils were collected Fall 2010 Site A: P. terrestris, R. vagum, C. coccodes, Fusarium spp. Site B: P. lycopersici, P. terrestris, R. vagum, C. coccodes, Fusarium spp. Site C: P. lycopersici, C. coccodes, Fusarium spp. P. capsici symptoms were also observed in the trial.

12 GREENHOUSE TRIAL2 Treatment A.I. Rate Timing Control Vapam High Metam sodium 0.36 ml/kg soil 10 DBT Vapam Low Metam sodium 0.18 ml/kg soil 19 DBT Actigard Five Acibenzolar-S-methyl 87.5 mg/l 4 DBT + 7, 15, 24 & 31 DAT Actigard Four Acibenzolar-S-methyl 87.5 mg/l 7, 15, 24 & 31 DAT Serenade Max Bacillus subtilis QST g/cell, in 3 ml water Promix Biofungicide 4 DAE Bacillus subtilis MBI 600 n/a At seeding Mycostop Streptomyces griseoviridis K % v/v in 200 ml/m 2 4 DAE

13 Figure 3. Number of lesions per gram of dry root on tomato roots grown in infested three different soils under greenhouse conditions and treated with various materials for management of vine decline symptoms, Ridgetown, 36 DAT, Trial ns # Lesions / g dry root ns ns Other Tip Banded Total 5 ns 0

14 Dry Root weight (g) % Change in Height Figure 4. a) Dry root weight and b) % change in plant height of tomatoes grown in three different infested soils under greenhouse conditions and treated with various materials for management of vine decline symptoms, Ridgetown, 36 DAT, Trial ab Control Vapam-H Vapam-L Actigard-5 Actigard-4 Serenade Promix Mycostop bc a bc ab c b ab Control Vapam-H Vapam-L Actigard-5 Actigard-4 Serenade Promix Mycostop b bc ab a ab bc b a a) b)

15 MICRO-PLOT TRIALS Infested soil from commercial Site A was collected in 2010, placed in micro-plots Trial was repeated in 2011 with the following soils: Soil from Site A, collected and treated in 2010 Soil from Site A, collected and treated in 2011 Soil from Site D, collected and treated in 2011 Treatment A.I. Rate Timing Nontreated Vapam - Low Metam sodium 0.18 ml/kg soil - Vapam - High Metam sodium 0.36 ml/kg soil - Actigard 1x Acibenzolar-S-methyl 1 ml/plant (87.5 mg product/l) Actigard 2x Acibenzolar-S-methyl 1 ml/plant (87.5 mg product/l) 10 DBT (drench) 10 DBT + 7 DAT (drench)

16 AAFC-MICROPLOTS 2010 No Fumigation Vapam High Rate

17 Table 1. Number and weight of tomato fruit harvested, and number of lesions per cm of root, from tomatoes grown in micro-plots in soil previously associated with vine decline symptoms in processing tomato, Soil A, London ON, Treatment % Increase over Control Weight (kg) Lesions/cm Root Nontreated b a 1.9 ns Vapam - MEDIUM ab 1.9 Vapam - HIGH a 1.5 Actigard 1x (10) 1.37 b 2.6 Actigard 2x ab 2.0 a Numbers in a column followed by the same letters are not significantly different at P = 0.05, based on Tukey s adjustment, ns = not significant. -Did death of microorganisms result in a release of nutrients? -Was soil repopulated with different spectrum of microorganisms?

18 Table 2. Weight of tomato fruit harvested from tomatoes grown in micro-plots in soil previously associated with vine decline symptoms in processing tomato, a) Soil A10, b) Soil A11, c) Soil D, and d) all soils, London ON, Treatment Soil A10 Soil A11 Increase (%) Weight (kg) Increase (%) Weight (kg) Nontreated ns ns Vapam - MEDIUM Vapam - HIGH (10) 1.55 Actigard 1x (12) 1.52 Actigard 2x Soil D All Soils Nontreated ab ns Vapam - MEDIUM a Vapam - HIGH ab Actigard 1x (13) 1.37 b (9) 1.26 Actigard 2x (6) 1.48 b a Numbers in a column followed by the same letters are not significantly different at P = 0.05, based on Tukey s adjustment, ns = not significant.

19 COMMERCIAL FIELD TRIALS Site A Reported root rot and vine decline on tomatoes in Small plot trial conducted in 2010 and Control, medium and high rate of Vapam Treatment Gallons/Acre Litres/Acre Litres/Hectare Nontreated Vapam - LOW Vapam - HIGH Site D Adjacent to a site with severe root rot and vine decline symptoms in Strip trial conducted in Treatment Gallons/Acre Litres/Acre Litres/Hectare Nontreated Vapam - LOW Vapam - HIGH

20 Figure 5. Tomato yield from plants grown in soil fumigated with Vapam (metam sodium) for management of tomato vine decline, Site A, 2010 & ns Yield (kg) ns Nontreated Vapam - LOW Vapam - HIGH -Total yield from two 2m sections in each replicate

21 Figure 6. Tomato yield from plants grown in soil fumigated with Vapam (metam sodium) for management of tomato vine decline, Site D, ns 30.0 Yield (t/acre) Control Low High

22 CONCLUSIONS & ONGOING RESEARCH Vapam is not a consistently effective tool for improving yield associated with root rot fungi and vine decline. Greenhouse Trials: Reduction in root lesions not consistent. Increase in root dry weight as compared to the control treatments is not consistent. No increase in plant height as compared to the control (Trial 2). Micro-plot Trials: Yield increase in 2010 was not observed again in the same soil in No statistically significant differences in yield when data from different locations was combined. Field Trials: No statistically significant differences in yield in two small plot field trials and one large scale strip trial.

23 ONGOING RESEARCH Determine if the spectrum of organisms present varies by treatment or over time. DNA samples have been collected from tomato roots in the different trials analysis forthcoming. Numerous other projects are underway by our group and others to explore alternative management methods and better understand the complex of root rot pathogens and their relationship with vine decline and yield.

24 ACKNOWLEDGEMENTS Ontario Tomato Research Institute Grower cooperators who donated soil, research sites, and fumigation services Agris, UAP, Heinz, Amvac, Sunbrite, Maizex for donating supplies, materials, and technical assistance OMAFRA / U of G Research Program Agriculture and Agri-Food Canada Janice LeBoeuf, OMAFRA Ed Tomecek, Tomecek Agronomic Services