Effect of Biopesticides on the Control of Leaf Spot in Adenophora triphylla var. japonica Hara.
Background : Adenophora triphylla var. japonica Hara. is one of the important oriental medicinal herbs being used to cure lung/respiratory diseases. It belongs to the five Sam (ginseng) including Panax ginseng, Salvia miltiorrhiza, Sophora flavescens, and Scrophularia buergeriana. In 2015, Korea produced 72 tons of medicinal herbs in a 14-hectare area and imported 24 tons valued at US$95,000. This study was carried out to investigate the effect of several biopesticides to control leaf spot of A. triphylla var. japonica Hara. Methods and Results : One year plants at the Department of Herbal Crop Research, NIHHS, RDA were used. The treatments used biopesticides such as plant extracts (BP), microbial agent (DM), microbial agent (PJ), sulfur powder (HS), and controlled chemicals (ST), while non treatment (NT) was used as control. After the early part of disease outbreak, the plants were treated four times with 7 days interval. The incidence of leaf spot, efficacy, phytotoxicity and control value were investigated. Based on the efficacy test, incidence of leaf spot is lowest at 15.6% in plant extracts (BP). Other biopesticides showed higher incidence - 16.7% for microbial agent (DM), 17.8% for microbial agent (PJ), 18.9% for sulfur powder (HS) and 71.1% for non treatment (NT), compared with 11.1% in controlled chemicals (ST). The microbial agent (PJ), sulfur powder (HS), plant extracts (BP) and microbial agent (DM) were not damaged in the phytotoxicity test. In the test of application dose, time and methods, the control value was highest in plant extracts (BP) at 78.1%, followed by microbial agent (DM) at 76.6%, microbial agent (PJ) at 75.0%, and sulfur powder (HS) at 73.4% , compared with controlled chemicals (ST) at 84.4%. Conclusion : It is possible to use biopesticides at the proper time to prevent leaf spot in Adenophora triphylla var. japonica Hara.