White Rot (Sclerotium Cepivorum) of Onions in Worcestershire With Special Reference to Control by Seed Treatment With Calomel

Observations in Worcestershire have shown that heavy losses of salad onions due to white rot may occur on sites which have not been known to carry a previous susceptible crop. Reasons for this are discussed. During five seasons a good control of the disease has been obtained by treating the seed with pure calomel applied with a resin‐alcohol sticker. The treatment also gave some control of damping off of seedlings due to Corticium solani. Broadcasting 4 % calomel dust at 2½‐3 cwt. per acre was less satisfactory in controlling white rot. In one season promising results were obtained with seed treatment of bulb onions.