b'There are a lot of proprietary chip varieties grown and most have high solids, so bruise management is top priority to growers. MARK VANOOSTRUM Shatter bruisein potato. PHOTO: PAT DOLWere shipping potatoes right now in June that were harvested last year in September, says VanderZaag. Theyve been sitting in storage for nine months, but theyre coming out as if they were harvested yesterday. And thats all about storage technology and storage management that makes that possible.VARIETY-SPECIFIC MANAGEMENT TECHNIQUESWhile these suggestions provide a good start, todays potato farmer must also consider variety-specific management techniques. To maintain the highest level of quality in storage, stringent management is required from variety to variety, says Mark VanOostrum, WD Potato Limited agronomist and supply manager, whose expertise is in chipping potato varieties. Field fry potatoes are susceptible to some types of bruise, but not pressure bruise, since they go direct from field to fryer. The Atlantic variety, for example, is susceptible to white knot bruise, which VanOostrum says can be mitigated by harvesting in temperatures warmer than 12 C. Check fields prior to harvest, and leave lower solids fields for later in the fall, says VanOostrum. Harvest when soils and frost can occur.Andover is more susceptible to bruise and should be harvested in colderA mechanically temperatures.bruised tuber. Dakota Pearl has good tolerance to blackspot and mechanical bruise due toPHOTO: PAT DOLlower solids, a tougher skin and genetic tolerance. The variety works well in heavy textured soil and fields with stones. It should be harvested in colder temperatures. For potatoes going into storage, variety-specific management applies to Lamo-ka, Dakota Pearl, Waneta and Marcy. Lamoka has thin skin, so its susceptible to pressure bruise, says VanOostrum. Allow three to four weeks post-vine kill for harvest, and try to assist as muchWaneta is a low solid, good skin, round potato that makes for a good candidate natural senescence as possible, he says. Consider planting early in a variety mixin heavy texture, stony fields and cooler pulp temperatures. It has good bruise in lower fertility fields, and harvest later in the season when pulp temperatures aretolerance, and tolerance to very cold pulp temperatures of less than 10 C, similar closer to curing temperatures of 12 to 13 C.to Dakota Pearl, but significantly better than all other commercial chip varieties.Lamokas smooth round to oblong shape makes them flow nicely, and notMarcy is susceptible to blackspot bruise and pressure bruise, says VanOo-particularly susceptible to blackspot or white knot, he adds.strum. To mitigate bruise, ensure pulp temperature is greater than 12 C at harvest, Typically, Dakota Pearl is harvested early in the season when warmer tem- and that theres lots of humidity in storage. Marcy is best stored at temperatures peratures occur. This makes them susceptible to pressure bruise, since extendedaround 9 C. fan time is needed to cool them. VanOostrum suggests adding refrigerationThere are a lot of proprietary chip varieties grown and most have high solids, and shipping early in the storage window (before the end of January) to reduceso bruise management is top priority to growers, VanOostrum adds. Outside potential processing problems. He says they are very good on mechanical andof chipping, I would say the gold standard for commercial bruise tolerance, cold blackspot bruise, and can be grown in cloddy, stony fields and harvested later inharvest tolerance and long storage tolerance to pressure bruise would be Russet cooler temperatures.Burbank. 20 SPUDSMART.COM FALL 2019'