Efficacy of sodium hypochlorite treatments for control of Xanthomonas campestris pv. campestris in Brassica seeds

Abstract

Twelve brassica seed lots, naturally infected with Xanthomonas campestris pv. campestris (Xcc), were immersed in a 0.525 % NaClO (1:10 clorox) aqueous solution at 5 ml/g seed at 50-53 deg C for up to 15 min. In eight lots, with pathogen counts of less or equal 5.3 x 10** (6) CFU per 10,000 seeds, Xcc was not detected in liquid assay or direct plating of seeds following a 5 min soak treatment. In three more highly infected seed lots a soak time of 15 min was necessary to control Xcc. As a follow up, in one additional heavily infected seed lot (3.4 % seed infection) the 15 min treatment reduced infection considerably but did not eliminate Xcc. The 5 min treatment did not significantly reduce germination in seed lots with 76 % or higher germination before treatment. Germination was reduced in three lots after 10 min, and in four lots after 15 min treatment. Average seed germination following all of the NaClO treatments was significantly higher than seed germination after hot water treatment at 50 deg C for 20 min