Internal Dry Scale and Associated Bulb Rots of Onion

Onion growers and packers in the Pacific Northwest have observed a problem on red, white and yellow cultivars: internal dry scale. Bulbs affected by internal dry scale have dead inner scales that are susceptible to fungi, bacteria and yeasts, which can lead to rot. In addition to outlining the incidences and symptoms of internal dry scale and associated bulb rots of onion, this publication discusses the factors that contribute to it and suggests tactics for limiting it.