CHEMICAL AND BIOLOGICAL-CONTROL OF LEAF-BLIGHT AND ROOT-ROT CAUSED BYPHYTOPHTHORA-CACTORUM IN AMERICAN GINSENG

Three chemical treatments, metalaxyl, metalaxyl + mancozeb, and fosety l-Al, and two biological treatments, Enterobacter aerogenes (B8) and B acillus cereus-complex (GB10), were evaluated for control of leaf blig ht and root rot of American ginseng caused by Phytophthora cactorum. M etalaxyl, metalaxyl + mancozeb, and GB 10 significantly reduced leaf i nfection in two separate experiments (P = 0.0003 and 0.0138). Metalaxy l alone or in combination with mancozeb and GB 10 significantly (P = 0 .0093) reduced root rot except in the second year of experiment 1. The se results suggest that metalaxyl and bacterial isolate GB 10 have the potential to control phytophthora leaf blight and root rot under fiel d conditions.