JacobsenControlPotato Fusar

Control of Potato Fusarium Dry Rot,  Silver Scurfand Soft rot with BioSave 110 and 1000: 

Control of Potato Fusarium Dry Rot, Silver Scurf and Soft rot with BioSave 110 and 1000 Barry J. Jacobsen Department of Plant Sciences and Plant Pathology Montana State University

Fusarium Dry Rot: 

Fusarium Dry Rot Fusarium sambucinum and other Fusarium sp. Infects through injuries to the periderm Found in all potato growing areas Managed by avoiding injuries, allowing wound healing in early storage Mertect (thiabendazole), many isolates resistant worldwide-approximately 50% in MT

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Typical infection through injury

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Bruised not inoculated Bruised and inoculated with F. sambucium Fusarium Dry Rot

Soft Rot: 

Soft Rot Erwinia carotovora pv. carotovora Common soil inhabitant Infection through wounds commonly follows other pathogens, frost Manage in much the same way a Fusarium-elimination of free water is critical

Silver Scurf: 

Silver Scurf Helminthosporium solani Primarily seedborne Loss is from blemishes to tuber and excessive water loss during storage Management Disease free seed tubers Mertect (thiabendazole) spray going into storage-resistance is widespread

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Silver scurf Blemish on red potato Blemish and sporulation on white/russet

Post Harvest Management of Dry Rot and Silver Scurf: 

Post Harvest Management of Dry Rot and Silver Scurf Dry / cold harvest conditions and variety susceptibility (Umatilla) make avoiding injury to periderm difficult. Curing period-warm temperature/high humidity for 7-10 days in initial storage allows injuries to cork over-this is not always effective Labeling of Mertect (thiabendazole) in early 80s provided excellent control when applied as spray during storage piling. Resistance was widespread within a few years. Growers need alternative control for dry rot and an effective control for silver scurf

BioSave 110 and BioSave 1000: 

BioSave 110 and BioSave 1000 Two different formulations of Pseudomonas syringae strains ESC 10 and ESC 11 marketed by EcoScience Widely used for management of post harvest diseases in apple, pear and citrus-EPA exempt from tolerance. Products are sold as frozen pellets (ultra cold) or sold as freeze dried product (BioSave 10 LP) that can be stored in regular freezer. Once mixed it must be used in 24 hrs. Applied as drench or spray as crop goes into storage (2 qt dilute spray per ton of potato applied by nozzle on belt or rotatary disc application as potatoes are piled in storage)

Development on Potato: 

Development on Potato Our lab had on going project on Fusarium dry rot management using Bacillus strains EcoScience asked us and Gale Kleinkopf (Univ. of Idaho) to evaluate ESC 10 (Biosave 100, 1000). Testing started in 1997 with controlled bruising / inoculation/ storage experiments

Procedures: 

Procedures Freshly harvested potatoes (Russet Norkotah, Shepody, Russet Burbank, Red Norland) washed free of soil. Bruised with hammer or in bruise box Inoculated with 1 x 105 cfu/ml F. sambucium, Helminthosporium solani- spray to wetness. Erwinia swabbed on with Q tip 1 x 108 cfu/ml Spray test bacteria @ log 7-8 Place in storage (4 C, 95% rh) 7-12 weeks-Fusarium/Helminthosporium. Erwinia stored at 25 C Cut tubers so decayed area can be examined or evaluated surface area infected by silver scurf

1997 Storage Trial-7 weeks: 

1997 Storage Trial-7 weeks

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1997

1998 Mertect Resistant: 

1998 Mertect Resistant

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ck Inoc-ck ESC 10 ESC 11 Mertect resistant

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1998-Toston-Russet Norkotah

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1998-Toston, MT 2 qt/ton

1998-99 Field Trial Procedures: 

1998-99 Field Trial Procedures Russet Norkotah potatoes harvested and delivered to storage Treated on unloading belt @ 2qt liquid per ton-100 ppm Mertect, log 8 Biosave products 5 100lb burlap sacks of each treatment placed in bottom of 15 ft storage pile-6 months storage Tubers washed and cut longitudinally rated for dry rot and silver scurf

1998-1999 Toston-Fusarium Dry Rot-Silver Scurf-Russet Norkotah: 

1998-1999 Toston-Fusarium Dry Rot-Silver Scurf-Russet Norkotah

Silver Scurf- 2002 Norland: 

Silver Scurf- 2002 Norland

Conclusions: 

Conclusions Biosave 110 and 1000 effective in reducing loss from both Fusarium dry rot and silver scurf BioSave 1000 marginally better than 110 Both products are effective on Mertect resistant F. sambucium and optimal control occurs when both products are used. Grower results have been excellent-new formulation BioSave 10 LP will be more convenient for growers.

Grower reports: 

Grower reports New BioSave formulations are more convenient Multiple year users (Buyan, Tobel) no Fusarium losses in 3 years since using BioSave even on Umatilla (very susceptible to Fusarium dry rot-other growers have had high losses. No grower reports on silver scurf

2002 Soft Rot-30 and 60 days storage @ 250 C- 2002 Norland: 

2002 Soft Rot-30 and 60 days storage @ 250 C- 2002 Norland

MSU 620: 

MSU 620 Muscoder alba- endophytic fungus fro cinnamon Produces gases toxic to wide range of microorganisms-excellent against Pythium, Phytophthora, Rhizoctonia, Helminthosporium, Aphanomyces, Rhizopus, Botrytis, Erwinia, E. coli mycofumigant

Other Post Harvest Ideas: 

Other Post Harvest Ideas Sugarbeets pile storage- Rhizopus, Phoma, Rhizoctonia, Erwinia soft rot (frost)- tried in 2001 on frosted beets-results inconclusive Potato- soft rot, Phytophthora

Thank you: 

Thank you Dr. Nina Zidack Dr. Sebastian Kiewnick John Ansley David Barbison