Damping-off of Indian Lettuce Caused by Rhizoctonia solani AG-4

Youn-Gi Moon1   Se-Won Kim1   Hyun-Taek Seo1   Wan-Gyu Kim2,*   

1Wild Vegetable Research Institute, Gangwondo Agricultural Research and Extension Services, Pyeongchang 25300, Korea
2Global Agro-Consulting Corporation, Hwaseong 18330, Korea

Abstract

Damping-off symptoms were frequently observed on young plants of Indian lettuce (Lactuca indica) grown in a farmer's vinyl greenhouse located in Goseong, Gangwon province of Korea during a disease survey in June 2019. The incidence of diseased plants in the vinyl greenhouse investigated was 30-50%. Four isolates of Rhizoctonia sp. were obtained from the diseased plants and identified as Rhizoctonia solani AG-4 based on the morphological characteristics and anastomosis test. Three isolates of R. solani AG-4 were tested for pathogenicity on Indian lettuce by artificial inoculation. All the tested isolates induced damping-off symptoms on the inoculated plants. The symptoms were similar to those observed in plants from the farmer's vinyl greenhouse investigated. This is the first report of R. solani AG-4 causing damping-off in Indian lettuce.

Figures & Tables

Fig. 1.Damping-off symptoms of Indian lettuce plants. A and B, symptoms observed in the vinyl greenhouse investigated; C, symptoms induced by artificial inoculation tests with AG-4 isolates. D, noninoculated plants (control).