Organic amendment of commercial culture media for improving control ofRhizoctoniadamping-off of cabbage

Abstract

Rhizoctonia solani AG-4 is an important damping-off pathogen of cabbage. Using a baiting technique, R. solani was recovered from the cabbage seeds buried in nine commercial culture media. The frequency of seed colonization by R. solani varied with medium, ranging from 2.5% in Nev-3 to 30% in Floradur A and SI 2; the seeds were examined after being buried for 48 h. Among the five formulated organic compounds tested as amendment for the commercial BVB No. 4 medium, FBN-5A was most effective in controlling damping-off. Although both rates of FBN- 5A, 0.1% and 0.2%, significantly reduced incidence of damping-off, FBN-5A at 0.1% was the more suitable treatment because it not only reduced the disease incidence, but also enhanced the growth of cabbage. The results were confirmed in a large-scale experiment in a commercial automatic environment-controlled greenhouse. This study suggests that the FBN-5A compound offers potential for commercial use as an organic amendment for the management of Rhizoctonia damping-off of vegetable crops.