Submitted to: Potato Conference and Trade Fair Proceedings
Publication Type: Proceedings
Publication Acceptance Date: February 19, 2002
Publication Date: March 20, 2002
Citation: BROWN, C.R., CORSINI, D.L. CONTROL DE ENFERMEDADES DE LA PAPA EN EL ALMACEN. PROCEEDINGS OF THE ANNUAL WASHINGTON STATE POTATO CONFERENCE AND TRADE FAIR, FEB. P 121-128. 2002. Interpretive Summary: As the end of the season approaches the manager of a potato crop still has may decisions to make that can affect the health and salability of the stored product. Harvest and transport of the potatoes should be done with an attitude of reducing mechanical damage as much as possible. Upon placing the potatoes in the storage the first principles are to make sure that the potatoes are dry on the surface, that the temperature is brought down first 55 degrees and then to 50, and that enough fresh air is flushed through storage to make sure that oxygen levels are sustained. Oxygen is necessary for the potatoes to heal wounds in the skin quickly and for the skin set, which is the growth of corky layer that forms a physical barrier against the entrance of pathogens. There are very few management tools that can reverse the onset of widespread rots in the storage other than low temperature and humidity that does not permit the surface of the tubers to be wet. The greatest benefit will be derived by applying these environmental factors at the right levels and in a timely manner, i.e., right at the onset of storage. The time during which potatoes are stored in inadequate circumstances is profit loss period.
Technical Abstract: Potatoes are a watery stem that must be stored for months at a time. They are also the host of numerous pathogens that start infection pre- and post-harvest and progressively damage the stored potatoes. Net necrosis caused by infection of potato leafroll virus is best controlled by control of the aphid vector during the growing season. Similarly, M. chitwoodi damage and corky ringspot disease caused by transmission of a virus into the tuber are addressed by pre-season fumigations. Tuber infection by the late blight organism is best prevented by well-time application of fungicides during the growing season and especially at the end of the crop until foliage is dead. But many rots are prevented or the damage minimized byproper handling and proper storage. Fusarium dry and pPythium leak are managed by careful non-bruising harvesting and transport of the potatoes into the storage unit. Once in the unit nearly all tuber rots are mitigated or stopped by applying sufficient air flow and lowering the temperature in a timely way. Free water adhering to tuger surfaces is to be avoided by taking immediate action. Potatoes should not be harvested in the rain. If condensation occurs in the storage the humidity and airflow should adjusted to so that there are no droplets on the potato. Fresh air brought in nightly is essential to maintain an oxygenated atmosphere as the respiring potatoes give off considerable carbon dioxide before the field heat is dissipated. A high oxygen atmosphere is necessary for wound healing and proper skin set. Varieties differ greatly in their propensity to rot when handled inappropriately and it is important to know these weakness and look for them.