Control of Pink Root Disease in Onion Using Solarization and Fumigation

Abstract

Effects of solarization and fumigation on control of pink root disease of onion ( Allium cepa L.) were determined in microplot studies in 1984. A 62-day solarization treatment significantly improved stand and productivity of ‘Granex 429’ onion while decreasing pink root expression. Metam-sodium fumigation gave equivalent improvement in stand and reduction in pink root expression, while causing an even greater onion growth response. Effects of these soil disinfestation techniques in onion seedbeds on subsequent field performance of onion transplants were examined in 1985–1986. Fumigation and solarization of individual soil beds virtually eliminated Pyrenochaeta terrestris infection of onion transplants. Seedbed treatment had no beneficial effect on yield, bulb diameter, or pink root expression at harvest when transplants were grown to maturity in an infested field. Chemical name used: sodium methyldithiocarbamate (anhydrous) (metam-sodium).