Open AccessCultivar and Fungicide Effects on Pythium Leak of Snap Bean
Author(s) -
J. P. Damicone,
Jenifer D. Olson,
Brian A. Kahn
Publication year - 2012
Publication title -
plant health progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.565
H-Index - 9
ISSN - 1535-1025
DOI - 10.1094/php-2012-0418-01-rs
Subject(s) - fungicide , pythium aphanidermatum , point of delivery , biology , pythium , cultivar , pythium ultimum , metalaxyl , horticulture , incidence (geometry) , agronomy , mathematics , rhizoctonia solani , biological pest control , geometry
Pythium leak is a pod decay complex of several pathogens and is a problem in the processing industry where snap beans are harvested in bulk. In Oklahoma, Pythium leak of snap bean is caused primarily by Pythium aphanidermatum and P. ultimum. Fungicide programs alone have not provided adequate disease control. The objective of this study was to evaluate snap bean cultivars for their reaction to Pythium leak with and without fungicide (mefenoxam + copper hydroxide) treatment. Entries were compared to the regional standards of Roma II for flat pod types and Nelson for round pod types. Over two years, disease incidence (DI = plants with symptoms) in untreated plots averaged 22% for Roma II and 30% for Nelson. Among the flat-pod types, entries that had less (P = 0.05) disease and yielded similar to, or greater than, Roma II included Bogota (DI = 13%), Navarro (DI = 12%), Romano 942 (DI = 12%), Cerler (DI = 10%), Tapia (DI = 10%), Primo (DI = 10%), and Ebro (DI = 5%). Among the round pod types, PLS 75 (DI = 14%) and SB 4261 (11%) had less disease than Nelson. However, all of the entries with round pods yielded less than Nelson. Over entries, fungicide treatment reduced disease incidence by an average of 40%, but the effect of fungicide was not significant for entries with low disease incidence such as PLS 75, Cerler, and Ebro. Except for plant height and lodging which were weakly correlated with disease incidence, plant architectural characteristics did not explain observed differences in disease incidence. Results suggest that reaction to Pythium leak is an important characteristic in selecting processing snap bean cultivars. Accepted for publication 30 January 2012. Published 18 April 2012.