Assessing the risk of resistance in Pseudoperonospora cubensis to the fungicide flumorph in vitro
- 20 December 2007
- journal article
- Published by Wiley in Pest Management Science
- Vol. 64 (3), 255-261
- https://doi.org/10.1002/ps.1515
Abstract
BACKGROUND: The oomycete fungicide flumorph is a recently introduced carboxylic acid amide (CAA) fungicide. In order to evaluate the risk of developing field resistance to flumorph, the authors compared it with dimethomorph and azoxystrobin with respect to the ease of obtaining resistant isolates to these fungicides, the level of resistance and their fitness in the laboratory. RESULTS: Mutants with a high level of resistance to azoxystrobin were isolated readily by adaptation and UV irradiation, and their fitness was as good as that of the parent isolates. Attempts to generate mutants of Pseudoperonospora cubensis (Burk. & MA Curtis) Rostovsev resistant to flumorph and dimethomorph by sporangia adaptation on fungicide‐treated leaves were unsuccessful. However, moderately resistant mutants were isolated using UV mutagenesis, but their resistance level [maximum resistance factor (MRF) < 100] was much lower than that of the azoxystrobin‐resistant mutant (MRF = 733). With the exception of stability of resistance, all mutants showed low pathogenicity and sporulation compared with wild‐type isolates and azoxystrobin‐resistant mutants. There is cross‐resistance between flumorph and dimethomorph, suggesting that they have the same resistance mechanism. CONCLUSION: The above results suggest that the resistance risk of flumorph may be similar to that of dimethomorph but lower than that of azoxystrobin and can be classified as moderate. Thus, it can be managed by appropriate product use strategies. Copyright © 2007 Society of Chemical IndustryKeywords
This publication has 15 references indexed in Scilit:
- Inheritance of resistance to carboxylic acid amide (CAA) fungicides in Plasmopara viticolaPlant Pathology, 2007
- Sensitivity of Phytophthora infestans to flumorph: in vitro determination of baseline sensitivity and the risk of resistancePlant Pathology, 2006
- The Generation and Quantification of Resistance to Dimethomorph in Phytophthora infestansPlant Disease, 2004
- A critical evaluation of the role of alternative oxidase in the performance of strobilurin and related fungicides acting at the Qo site of Complex IIIPest Management Science, 2003
- The strobilurin fungicidesPest Management Science, 2002
- Sensitivity to Azoxystrobin Among Isolates of Uncinula necator: Baseline Distribution and Relationship to Myclobutanil SensitivityPlant Disease, 2002
- Laboratory studies to assess the risk of development of resistance to zoxamidePest Management Science, 2001
- Distribution of Baseline Sensitivities to Azoxystrobin Among Isolates of Plasmopara viticolaPlant Disease, 2000
- Alternative Respiration: a Biochemical Mechanism of Resistance to Azoxystrobin (ICIA 5504) inSeptoria triticiPesticide Science, 1997
- Selection and characterization ofPhytophthora parasiticamutants with ultraviolet-induced resistance to dimethomorph or metalaxylPesticide Science, 1993