POTATO STORAGE FACILITIES AND HANDLING EQUIPMENT CAN GET PRETTY MESSY AFTER A SEASON'S WORTH OF USE. FOR THIS REASON, STORAGES AND EQUIPMENT NEED TO BE CLEANED AND DISINFECTED IN PREPARATION FOR HARVEST ACTIVITIES. PROPER CLEANING AND DISINFECTION IS ESPECIALLY IMPORTANT IF YOU ACQUIRED USED EQUIPMENT AT AN AUCTION OR SALE, IF THE EQUIPMENT WAS LAST USED ON RENTED GROUND OR IT WAS USED IN FIELDS THAT ARE SUSPECTED OR KNOWN TO HAVE CONCERNS WITH NEMATODES, WEEDS OR SOIL-BORNE DISEASES. BECAUSE OF THESE PROBLEMS, IT IS IMPORTANT TO REMOVE SOIL ADHERING TO YOUR EQUIPMENT BEFORE ENTERING ANY OF YOUR FIELDS. SOME TYPES OF EQUIPMENT HAVE A MUCH GREATER POTENTIAL THAN OTHERS TO RETAIN SIGNIFICANT LEVELS OF ADHERING SOIL. HARVESTERS AND WINDROWERS COME TO MIND IMMEDIATELY. PRESSURIZED WATER AND PORTABLE STEAM CLEANING UNITS ARE A VITAL PART OF ANY CLEAN-UP PROGRAM, AND GOOD OLD-FASHIONED DETERGENT IS ALSO AN INVALUABLE TOOL. THE FIRST STEPS IN THE CLEANING PROCESS INVOLVE EVEN MORE BASIC TOOLS, LIKE A BROOM AND A SHOVEL.
REMOVING FOREIGN MATERIAL
ANY STORAGE THAT WILL HOLD POTATOES NEEDS TO BE CLEANED PRIOR TO LOADING. FIRST, THE STORAGE NEEDS TO BE CLEANED UP OF ANY FOREIGN MATERIAL. REMOVE ALL PLANT, POTATO AND UNWANTED MATERIAL FROM THE STORAGE, FLOOR, PLENUM AND PIPES. INSPECT THE STORAGE FOR ANY NEEDED REPAIRS SUCH AS LOOSE INSULATION OR METAL OR BROKEN WOOD. LOOK FOR AREAS IN THE WALL PANELS WHERE SCREWS MAY HAVE COME LOOSE OR HAVE FALLEN TO THE FLOOR. DON'T FORGET ABOUT REMOVING OLD DUCT TAPE FROM DUCT PIPES OR FROM THE FLOOR. WHEN LAST YEAR'S POTATOES WERE REMOVED FROM THE STORAGE, TRASH AND OLD TUBERS MAY HAVE COLLECTED IN VARIOUS AREAS OF THE CELLAR. AN EASY WAY TO REMOVE THIS MATERIAL IS TO RAKE INTO PILES AND LOAD INTO A WHEELBARROW OR TRASH CAN.
AFTER THE STORAGE BUILDING HAS BEEN INSPECTED AND CLEANED OF ALL VISIBLE MATERIAL, THE NEXT STEP IS TO PASS A MAGNET OVER THE FLOOR. THE MAGNET WILL COLLECT ANY IRON-CONTAINING METAL MATERIALS THAT WERE MISSED IN THE CLEANING PROCESS. THESE MAGNETS WILL PICK UP NAILS, SCREWS, WIRE AND OTHER SIMILAR MATERIALS. A SMALLER MAGNET CAN BE USED IN HARD-TO-REACH AREAS SUCH AS CELLAR CORNERS. DOUBLE CHECK THE STORAGE LIGHTS FOR SHATTERPROOF COVERINGS. DON'T FORGET ABOUT THE OUTSIDE OF THE STORAGE AS WELL. CLEAN UP ANY TRASH THAT MAY HAVE ACCUMULATED OUTSIDE THAT COULD EASILY MOVE INSIDE WITH THE POTATOES DURING LOADING.
DISEASE PREVENTION
THE SECOND COMPONENT OF CLEANING IS WASHING AND DISINFECTING YOUR STORAGE TO HELP MINIMIZE DISEASE CARRYOVER FROM ONE STORAGE SEASON TO THE NEXT. REMOVE ALL PLANT DEBRIS FROM THE CELLAR FLOORS AND PIPES. IF POSSIBLE, REMOVE THE TOP 1-2 INCHES OF THE DIRT FLOOR AND REPLACE WITH SOIL NOT ASSOCIATED WITH POTATO PRODUCTION. THE ENTIRE INSIDE OF THE STORAGE NEEDS TO BE THOROUGHLY CLEANED INCLUDING WALLS, BEAMS, INSULATION, CEMENT, DIRT FLOORS, PLENUMS, DUCTS, PIPES AND VENTILATION AND HUMIDIFICATION SYSTEMS. THOROUGHLY WASH ALL COMPONENTS OF THE STORAGE FACILITY WITH SOAP AND HOT WATER OR STEAM USING A HIGH-PRESSURE SPRAYER AND THEN RINSE. NEXT APPLY THE DISINFECTANT AND ALLOW THE SURFACES TO REMAIN WET FOR AT LEAST 10 TO 15 MINUTES TO BE FULLY EFFECTIVE. CLOSE UP THE STORAGE FACILITY FOR TWO WEEKS AND THEN REOPEN TO AIR AND DRY OUT THE FACILITY.
THERE ARE MANY PRODUCTS AVAILABLE FOR STORAGE DISINFECTION AND IT IS IMPORTANT TO CHOOSE PRODUCTS BEST SUITED FOR YOUR STORAGE PROGRAM AND FACILITY. ALWAYS CHECK THE LABEL AND ANY SUPPLEMENTAL LABEL FOR A) SAFETY CONCERNS, B) WHETHER THE PRODUCT IS LABELED FOR POROUS, NON-POROUS OR DIRECT-POTATO APPLICATION, AND C) WHETHER IT IS LABELED FOR THE STORAGE FACILITY AND/OR POTATO HANDLING EQUIPMENT. POROUS MATERIALS INCLUDE PERMEABLE SURFACES SUCH AS DIRT FLOORS, WOOD AND INSULATION. NON-POROUS MATERIALS INCLUDE NON-PERMEABLE, HARD SURFACES SUCH AS METAL AND CONCRETE. THE MATERIALS COMPRISING YOUR STORAGE FACILITY WILL HELP DECIDE WHICH TYPES OF DISINFECTANT PRODUCTS WOULD BE BEST SUITED FOR DISINFECTING YOUR STORAGE. SOME DISINFECTANT PRODUCTS (E.G. HYPOCHLORITE) BECOME INACTIVATED BY ORGANIC MATTER AND THEREFORE WOULD NOT BE AS EFFECTIVE ON DIRT FLOORS AND WOOD. PRODUCTS SUCH AS SODIUM AND CALCIUM HYPOCHLORITE AND CHLORINE DIOXIDE CAN BE CORROSIVE TO METALS. THERE ARE MANY PRODUCTS AVAILABLE WITH VARIOUS PERCENTAGES OF ACTIVE INGREDIENTS AND ALLOWABLE APPLICATION RATES AND METHODS. SIMPLY APPLYING A DISINFECTANT ALONE IS NOT RECOMMENDED AS AN EFFECTIVE OVERALL CLEANING OF THE STORAGE.
IF SILVER SCURF HAS BEEN A PERENNIAL PROBLEM, PROPER STORAGE CLEANING AND APPLICATION OF THE APPROPRIATE DISINFECTANT MAY HELP DECREASE THE SURVIVAL OF SILVER SCURF FROM LAST STORAGE SEASON TO THIS YEAR. PREVIOUS UNIVERSITY OF IDAHO RESEARCH HAS SHOWN THAT SILVER SCURF (HELMINTHOSPORIUM SOLANI) CAN SURVIVE ON FOAM INSULATION AND SOIL FLOORS FOR UP TO NINE MONTHS, AND ON SHEET METAL UP TO THREE MONTHS. BACTERIAL RING ROT CAN SURVIVE ON HARD SURFACES FOR UP TO THREE YEARS AND UP TO SEVEN YEARS ON WOOD SURFACES. SO PROPER CLEANING AND DISINFECTION OF STORAGES IS AN IMPORTANT COMPONENT OF AN OVERALL DISEASE MANAGEMENT PROGRAM.
THE ORGANISMS THAT CAUSE DISEASE IN POTATOES ARE CAPABLE OF SURVIVING ON STORAGE SURFACES AND ON EQUIPMENT UNDER SOME FAIRLY HARSH CONDITIONS. WHILE IT WOULD SEEM TO MAKE SENSE THAT SIMPLY PLACING YOUR EQUIPMENT OR DUCT PIPES OUT IN THE SUN FOR A FEW DAYS WOULD GO A LONG WAY TOWARD DISINFECTING THEM, SUCH IS NOT THE CASE. THE BACTERIAL PATHOGENS RESPONSIBLE FOR SOFT ROT AND BACTERIAL RING ROT CAN READILY SURVIVE IN SUCH CONDITIONS. THEY DO SO IN CLUMPS OF CELLS SURROUNDED AND PROTECTED BY DRIED BACTERIAL SLIME. FORMATION OF THESE CLUMPS NOT ONLY ALLOWS SOME BACTERIAL CELLS TO SURVIVE BUT THE CLUMPS OF DRIED SLIME ALSO CAN BE VERY DIFFICULT TO REMOVE. EXPOSURE TO SUNLIGHT WOULD BE A GOOD FINAL STEP IN THE CLEANING OF EQUIPMENT OR PLENUM PIPES, AFTER THEY HAVE BEEN THOROUGHLY WASHED AND DISINFECTED.
CLEANING YOUR STORAGE IS ALSO AN IMPORTANT STEP ONCE THE CROP IS REMOVED AND PRIOR TO STORING SEED POTATOES FOR CUTTING AND PLANTING. THE CONCERN FOR SPROUT INHIBITOR CHLORPROPHAM (CIPC) RESIDUE REMAINING IN THE STORAGE AND THE POTENTIAL IMPACT ON THE SEED CANNOT BE OVERLOOKED. SEVERE DELAYS IN EMERGENCE AND GROWTH CAN OCCUR IF SEED IS EXPOSED TO CIPC RESIDUES. IT IS RECOMMENDED TO AVOID STORING SEED IN A STORAGE THAT HAS BEEN TREATED WITH CIPC UNTIL ONE YEAR HAS LAPSED SINCE TREATMENT AND THE STORAGE HAS BEEN THOROUGHLY CLEANED.
FOR ADDITIONAL INFORMATION, THE UNIVERSITY OF IDAHO HAS TWO VIDEOS THAT OUTLINE WAYS TO REDUCE FOREIGN MATERIAL IN POTATOES ("MINIMIZING FOREIGN MATERIAL TO MAINTAIN QUALITY IDAHO POTATOES") AND PROPER CLEANING AND DISINFECTING OF POTATO STORAGES ("CLEANING AND DISINFECTING POTATO STORAGES"). VISIT THE IDAHO CENTER FOR POTATO RESEARCH AND EDUCATION WEBSITE FOR MORE INFORMATION AT WWW.AG.UIDAHO.EDU/POTATO.