Presentation on theme: "Disease Control Products for Stored Potatoes"— Presentation transcript:
1Disease Control Products for Stored Potatoes Jill Thomson andDoug WatererDept of Plant Sciences, University of Saskatchewan
2Control of Storage Diseases Challenge - need dependable control of various diseases during storage/handlingChallenge - need safe, affordable productsChallenge - products must be readily applied with available equipment
3Control of Storage Diseases Traditional optionsMertec (TBZ)spray applied during load-ingood coverage criticalnot effective against bacterianot effective against Late Blightextensive resistance in Dry Rot and Silver scurf$ 6.40/tonne at CDN label rate
4Control of Storage Diseases Available optionsDithane (Mancozeb)spray applied during load-ingood coverage criticalnot effective against bacteriaeffective against Dry Rot and Silver scurf$ 11.06/tonneonly registered for use on seed
5Control of Storage Diseases Alternate optionsPurogeneOxidateOzone
6Control of Storage Diseases Purogene (Anthium)UAPSodium chlorite + acid = Chlorine dioxide (gas) + other Cl speciesapplied as spray to potatoes going into storage and/oradded to ventilation air
8Control of Storage Diseases Purogeneworks by oxidation reactionslabel indicates effective against L. blight, Silver Scurf, Dry Rot and Bacterial Soft rotinactivated by soilno residual activityrepeated or continuous treatment recommended
9Control of Storage Diseases Purogene - StatusResearched by MSU, NDSU, Idaho, MB and AB.5th year of Class 18 Exemption in U.S.Emergency use in Canada in 1999, 2000 and 2001 but not in 2002
10Control of Storage Diseases Purogene Efficacy against Soft rotMB datasome control
11Control of Storage Diseases Effect of Purogene on the amount of rot found on tubers (MANITOBA)Cultivar Concentration Avg Rot per Tuber (%)Russet BShepodyShepody
12Control of Storage Diseases Purogene vs Late BlightMB dataTubers treated immediately after inoculationsome control
13Control of Storage Diseases Purogene vs Rhizoctonia, Silver Scurf, Soft Rot and Dry RotAB dataTubers sprayed at load inTubers treated in storage (weekly)minimal control
14Control of Storage Diseases Purogene - Safetymixing step requires safety equipment (ClO2 vapors)ventilate storage for 2 h prior to re-entrypotatoes must be washed prior to consumptionslowly corrodes copper, brass, aluminum
15Control of Storage Diseases Purogene - Economics16-32 ml/ton applied at load-inmax rate of 16 ml/ton/month applied during storage humidifaction$25/L$ 2.50/ton for pre-treatment + continuous application over 5 months
16Control of Storage Diseases Purogene Conclusionsvariable resultsproblems getting full activationproblems with inactivation by soilproblems with uniformity of distribution of effective dosagesproblems with adding humidity to problem storagesrelatively safe and affordable
17Control of Storage Diseases OxidateBioSafeHydrogen Peroxide + acetic acidapplied as spray to potatoes going into storage and/oradded to ventilation air
18Control of Storage Diseases Oxidateworks by oxidation reactionslabel indicates effective against L. blight, Silver Scurf, Dry Rot and Bacterial Soft rotinactivated by soilno residual activitycontinuous treatment recommended
19Control of Storage Diseases Oxidate - Statusapproved in U.S. for use in wide range crops in field and storageapproved as an “organic” pesticide“Emergency Use” in BC and AB in 2002full registration anticipated for April 2003NB has done some testing in potatoes
24Control of Storage Diseases Oxidate - Safetyno mixing stepconcentrated product is corrosiveno re-entry restrictionno limit to amount appliedno requirement to wash prior to consumptionslowly corrodes copper, brass, aluminum
25Control of Storage Diseases Oxidate - Economics1-2% solution applied to wetness at load-in1:100 to 1:300 applied during storage humidifaction$17.78/Lpre-treatment = $ /tonne1% in humidification system = $1.78 per injectionHow many injections into system over 5 month period?
26Control of Storage Diseases Oxidate – Conclusionspotential to reduce disease levelshigh dosages and continuous application most effectivesafe and affordableneed uniform delivery of effective dosagesadding humidity to problem potatoes ?Impact on sprouting ??
27Control of Storage Diseases Ozonevarious manufacturersO2 + high energy = O3 (gas)applied at high levels to potatoes going into storage and/oradded to ventilation air
28Control of Storage Diseases Ozoneworks by oxidation reactionslab studies indicates effective against range of bacteria and fungiinactivated by soilno residual activitycontinuous treatment recommended
29Control of Storage Diseases Generator unit, outside storage
30Control of Storage Diseases Monitoring equipment mounted above conveyor. Injection of O3 into conveyor system, removal of excess O3.
31Control of Storage Diseases Ozone - Statuswell established in other food areasdata for storage use is limitedadvantage = does not depend on water for delivery (spray or humidity)
34Control of Storage Diseases Ozone – EfficacyO3 applied loading into storage
35Control of Storage Diseases Ozone - Safetywidely used to sanitize food and buildingscorrosive at high concentrationsexposure levels well establishedno limit to amount appliedno requirement to wash prior to consumption
36Control of Storage Diseases Ozone - Economicsgenerators + power500 ppm during loading2 ppm during storage ventilation$ ?
37Control of Storage Diseases Ozone - Conclusionsprimarily provides contact controlmost effective against surface problems (scurf and bacteria)ineffective against aggressive or well established infectionseconomics ?Impact on product/facilities ?
38Control of Storage Diseases ConclusionsPurogene and Oxidate demonstrated to provide some control under certain conditionsOzone also shows potentialMost effective against new, surface problemsSupplement to good harvest and storage management practices
39Control of Storage Diseases In the future ?No new chemical products in the pipelineBioCide is developing granular products for time-release usesHelp overcome short reaction times of chlorine dioxide and improve in-storage distributionFurther out … Bacterial antagonists to common diseases