METALAXYL SENSITIVITY AND AGGRESSIVENESS OF PHYTOPHTHORA COLOCASIAE ISOLATES ASSOCIATED WITH TARO LEAF BLIGHT DISEASE

Leaf blight caused by Phytophthora colocasiae is the most devastating disease of taro (Colocasia esculenta). P. colocasiae isolates belonging to four morphogroups were assessed for their aggressiveness and reaction to the metalaxyl fungicide Ridomil Gold 60WP. Based on sporangia morphology and partial β tubulin sequence homology all fungal isolates associated with and recovered from infected leaves were identified as P. colocasiae. Significant differences (P < 0.05) were observed among the isolates based on the various parameters (incubation period, lesion size and sporangia produced) taken into consideration. Similarly, the various isolates reacted differently to the test fungicide. Eleven of the isolates were considered to be moderately resistant, whilst 69 (86.2%) were found to be susceptible to the fungicide. None of the tested isolates was metalaxylresistant. Results of the study showed differences in the organism causing taro leaf blight disease in Ghana based on their aggressiveness potentials as measured by the epidemiological components. Also the lack of an identified resistant isolate shows the potential of employing metalaxyl based fungicide in managing taro leaf blight caused by P. colocasiae.

[1]  P. Doležal,et al.  Sensitivity to fungicides in the isolates of Phytophthora infestans (Mont.) de Bary in the Czech Republic from 2003 to 2008. , 2018 .

[2]  V. Nath,et al.  Morphological, pathological and molecular characterization of Phytophthora colocasiae responsible for taro leaf blight disease in India , 2015, Phytoparasitica.

[3]  J. Uchida,et al.  Mating Type Distribution, Fungicide Sensitivity, and Phylogenetic Relationships of Phytophthora colocasiae , 2014 .

[4]  A. McLeod,et al.  Phytophthora infestans populations in central, eastern and southern African countries consist of two major clonal lineages , 2013 .

[5]  D. Benson,et al.  Characterization of Phytophthora spp. on Floriculture Crops in North Carolina. , 2011, Plant disease.

[6]  A. Mishra,et al.  Characterisation of Phytophthora colocasiae isolates associated with leaf blight of taro in India , 2011 .

[7]  M. Hausbeck,et al.  Resistance of Pepper to Phytophthora Crown, Root, and Fruit Rot Is Affected by Isolate Virulence. , 2010, Plant disease.

[8]  C. Lannou,et al.  Aggressiveness and its role in the adaptation of plant pathogens , 2009 .

[9]  K. Lamour.  Phytophthora capsici: Sex, Selection, and the Wealth of Variation , 2008 .

[10]  E. Stromberg,et al.  Mefenoxam sensitivity and fitness analysis of Phytophthora nicotianae isolates from nurseries in Virginia, USA , 2008 .

[11]  F. Brooks.  Detached-Leaf Bioassay for Evaluating Taro Resistance to Phytophthora colocasiae. , 2008, Plant disease.

[12]  D. S. Shaw,et al.  Novel microsatellite markers for the analysis of Phytophthora infestans populations , 2006 .

[13]  K. Kageyama,et al.  Phylogenetic relationships of Pythium and Phytophthora species based on ITS rDNA, cytochrome oxidase II and β-tubulin gene sequences , 2006 .

[14]  P. E. Russell,et al.  A comparative study of XR-539 and other oomycete fungicides: similarity to dimethomorph and amino acid amides in its mechanism of action. , 2005 .

[15]  N. Suassuna,et al.  Aggressiveness and host specificity of Brazilian isolates of Phytophthora infestans , 2004 .

[16]  R. Steiner,et al.  Differentiation of race specific resistance to Phytophthora root rot and foliar blight in Capsicum annuum , 2003 .

[17]  D. J. Carlisle,et al.  Foliar aggressiveness of Northern Ireland isolates of Phytophthora infestans on detached leaflets of three potato cultivars , 2002 .

[18]  D. Inglis,et al.  Persistence of Complex Virulences in Populations of Phytophthora infestans in Western Washington. , 2001, Phytopathology.

[19]  G. Forbes,et al.  Impact of fungicide application and late blight development on potato growth parameters and yield in the tropical highlands of Kenya and Uganda , 2001 .

[20]  J. Ristaino,et al.  Commercial Fungicide Formulations Induce In Vitro Oospore Formation and Phenotypic Change in Mating Type in Phytophthora infestans. , 2000, Phytopathology.

[21]  J. Lucas,et al.  Aggressiveness and Competitive Fitness of Phytophthora infestans Isolates Collected from Potato and Tomato in France. , 1999, Phytopathology.

[22]  P. Bosland,et al.  Inheritance of Phytophthora Root Rot and Foliar Blight Resistance in Pepper , 1999 .