Thesis (M.S., Plant, Soil and Entomological Sciences) -- University of Idaho, 2016 | Onion is an ancient crop specie with around 5000 years of human cultivation. Nowadays, onions are worldwide cultivated with approximately 60 million of metric tons production in over 147 countries. Behind China and India, the USA is the thirds biggest country in onion production. In this way, the Pacific North West is the most important production area in dry onion for storing. In this area, onions are growth for holding in storage for around of 6 months, during the period where onions are not harvest in the USA. In normal years, loss in storage are not important, however in some years pathogens could cause important loss. In the last years the industry has been concerned about bacterial rot in storage, and some field conditions that could cause increase of pathogen rot. Therefore, field trial were conducted seeking underlying field conditions, and Macroarray technique was tested as a pathogen predictive approach.