Variation in Fungicide Sensitivity Among Rhizoctonia Isolates Recovered from Potatoes in South Africa
| Autor: | James W. Woodhall, J. E. van der Waals, N. Muzhinji, M. Truter |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
0106 biological sciences
0301 basic medicine Population Dioxoles Microbial Sensitivity Tests Plant Science Fludioxonil Rhizoctonia 01 natural sciences Pencycuron South Africa 03 medical and health sciences chemistry.chemical_compound Species Specificity Pyrroles education Plant Diseases Solanum tuberosum education.field_of_study Iprodione biology Hydantoins Phenylurea Compounds Benomyl Aminoimidazole Carboxamide Strobilurins biology.organism_classification Fungicides Industrial Fungicide Horticulture Pyrimidines 030104 developmental biology chemistry Azoxystrobin Agronomy and Crop Science 010606 plant biology & botany |
| Zdroj: | Plant Disease. 102:1520-1526 |
| ISSN: | 1943-7692 0191-2917 |
| Popis: | Rhizoctonia is a major pathogen of potato causing substantial yield losses worldwide. Control of Rhizoctonia diseases is based predominantly on the application of fungicides. However, little is known about the fungicide response variability of different Rhizoctonia anastomosis groups associated with potato diseases in South Africa. A total of 131 Rhizoctonia isolates were obtained from potato growing regions of South Africa from 2012 to 2014 and evaluated for sensitivity to fungicides in vitro and in vivo. The fungicides comprised six chemical formulations and one bio-fungicide representing seven Fungicide Resistance Action Committee groups. All Rhizoctonia anastomosis groups were sensitive to tolclofos-methyl (EC50: 0.001 to 0.098 μg a.i. ml−1) and fludioxonil (EC50: 0.06 to 0.09 μg a.i. ml−1) and showed variation in sensitivity to pencycuron, iprodione, benomyl, and Bacillus subtilis QST 713. However, for azoxystrobin, Rhizoctonia isolates exhibited variable sensitivity ranging from sensitivity (EC50: −1) to insensitivity with EC50 values exceeding 5 μg a.i. ml−1. In greenhouse and field trials, tolclofos-methyl and fludioxonil exhibited significantly greater control of stem and black scurf whereas azoxystrobin was the least effective. This work demonstrated variable sensitivity within and among anastomosis groups of R. solani and binucleate Rhizoctonia to different fungicides. Information on fungicide sensitivity of Rhizoctonia isolates is crucial in the development of effective Rhizoctonia control strategies and facilitates monitoring of fungicide insensitive isolates in the pathogen population. |
| Databáze: | OpenAIRE |
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