Abstract

PRUDENCIO-SAINS, José Manuel; NAVARRETE-MAYA, Rosa; NAVARRETE-MAYA, Jorge  and  ACOSTA-GALLEGOS, Jorge Alberto. Dynamics of the bean common and halo blights in the Valley of Mexico. Agric. Téc. Méx [online]. 2008, vol.34, n.2, pp.201-212. ISSN 0568-2517.

The objectives of this research were 1) to study the dynamics of the diseases bean common and halo blight during the crop cycle at the Valley of Mexico, under rainfed conditions and 2) to identify resistant cultivars to both bacterial diseases. Eleven bean cultivars, from different origin and contrasting growth habit, were sown on June 10, 2001 at Texcoco, State of Mexico. Incidence and disease severity were recorded at different growth stages and the incidence rate and area under disease progress curve (AUDPC) were also estimated. All cultivars showed incidence of both diseases, that of halo blight was higher than 50% from the end of flowering onwards, and common blight reached the same level until the beginning of seed filling. There was not relationship between disease susceptibility and cultivar growth habit. Seed yield was negatively affected by the development of both diseases and halo blight had a larger negative impact. The AUDPC described with major precision the effect of the diseases on the bean crop, in comparison with punctual readings of incidence and severity. Tolerant cultivars against both diseases were Bayo Madero, Negro 8025 and Pinto Villa.

Keywords : Phaseolus vulgaris L.; Pseudomonas syringae pv. phaseolicola; Xanthomonas axonopodis pv. phaseoli; weather conditions; resistance.