Fungicidal effects of two fumigants on Phellinus noxius in the soil

Abstract

Brown root rot caused by Phellinus noxius is a serious plant disease, and has been causing serious problem in tropical and subtropical regions. At present, the only effective control procedure is entirely removing infected trees and the surrounding soil. However, these measures are labor-intensive and time-consuming, therefore practical alternatives is necessary. We evaluated the effects of two fumigants chloropicrin and dazomet on P. noxius. Branches artificially inoculated with P. noxius were buried in soil and subsequently fumigated. After fumigation, the branches were collected and examined for the presence of P. noxius. No P. noxius was isolated from branches retrieved from chloropicrin-treated soil, whereas the isolation rate of P. noxius from dazomet-treated was significantly lower than the control. In addition, to confirm the workability and safe practical use of chloropicrin, we established a test plot (6.5 m×12 m). The treatment took 7 hours by 5 workers. During the test period, no gas leakage was detected outside the covering sheet. In addition, any gas was not detected inside the sheet, 11 days after fumigation treatment. We accordingly confirmed that chemical fumigation with chloropicrin and gas barrier film could be safely applied for control of P. noxius even at practical scale.