Efficacy of fungicides in controlling rice blast and dirty panicle diseases in Thailand

Nattapatphon Kongcharoen,Nipon Kaewsalong,Tida Dethoup

doi:10.1038/s41598-020-73222-w

Nattapatphon Kongcharoen, Nipon Kaewsalong + Show 1 more

Open Access

https://doi.org/10.1038/s41598-020-73222-w

Copy DOI

Journal: Scientific Reports	Publication Date: Oct 1, 2020
Citations: 42	License type: open-access

Affiliation: Kasetsart University

Abstract

In this study, the fungicidal activities of the fungicides azoxystrobin, difenoconazole + propiconazole, carbendazim, flutriafol, fluopyram + tebuconazole, mancozeb and thiophanate-methyl against rice blast and dirty panicle pathogens were evaluated under laboratory and field conditions. Mancozeb exhibited the highest level of fungicidal activity against the blast pathogen Pyricularia oryzae, with an EC50 value of 0.25 parts per million (ppm). The combination of two fungicides, fluopyram + tebuconazole, showed the strongest fungicidal effect against Bipolaris oryzae and Curvularia lunata, with EC50 values of 0.587 ppm and 0.435 ppm, respectively. Meanwhile, carbendazim and flutriafol demonstrated the best level of fungicidal activity against Fusarium incarnatum, with the lowest EC50 values of 0.211 ppm and 0.214 ppm, respectively. The results showed that the fungicides, triazole and strobilurin, had significant effects against rice blast and dirty panicle diseases. The combination of fluopyram + tebuconazole, when applied twice, was the most effective in reducing dirty panicle disease by up to 60% and increasing rice yield by 29% more than the untreated control. Fluopyram + tebuconazole, difenoconazole + propiconazole, flutriafol and azoxystrobin achieved stronger fungicidal activity against rice blast disease, reducing its severity by 32–33% when applied twice by foliar spraying. However, carbendazim, mancozeb and thiophanate-methyl had low to moderate fungicidal activity against both rice diseases in this study.

Highlights

In this study, the fungicidal activities of the fungicides azoxystrobin, difenoconazole + propiconazole, carbendazim, flutriafol, fluopyram + tebuconazole, mancozeb and thiophanate-methyl against rice blast and dirty panicle pathogens were evaluated under laboratory and field conditions
Fungicide application has been the effective option for controlling rice diseases in the crops of Thai farmers
Mancozeb showed a low level of activity against both rice blast and dirty panicle diseases in field tests when compared to the other fungicides (Tables 2, 3, 4)

Summary

Introduction

The fungicidal activities of the fungicides azoxystrobin, difenoconazole + propiconazole, carbendazim, flutriafol, fluopyram + tebuconazole, mancozeb and thiophanate-methyl against rice blast and dirty panicle pathogens were evaluated under laboratory and field conditions. Rice blast disease caused by Pyricularia oryzae (Magnaporthe grisea) has been reported as the most significant disease, resulting in yield losses of up to 50%1. Infected rice seeds are the source of the inoculum of the pathogenic fungi, which is distributed through seed storage to new crops This disease is a major cause of rice seed destruction and leads to losses in yield, both qualitatively and quantitatively, of up to 80%6. Reports of the mutation of guanine to a G143A or a G143S in Qo of cytochrome b resulted in M. oryzae strain resistance to the Qo-inhibiting fungicide a zoxystrobin[24], while over-expression of the phosphatase gene MoPTP2 in the Hog1p MAPK for osmoregulation revealed M. oryzae resistance to fludioxonil[25]

Objectives

Methods

Results

Conclusion