Abstract

ANDRADE-LUNA, Mauricio Iván et al. Severity of a Phytophthora capsici isolate in chayote Sechium edule plants at growth chamber level. Rev. mex. fitopatol [online]. 2017, vol.35, n.1, pp.40-57. ISSN 2007-8080.  https://doi.org/10.18781/r.mex.fit.1607-3.

The severity of Phytophthora capsici in chayote plants was determined and a scale of severity is proposed, given its recent confirmation as a causative agent of disease. Plants with wilting symptoms were sampled from two commercial chayote orchards in Huatusco, Veracruz, Mexico. The isolated oomycete, from fruits and stems, was characterized morphological and molecularly, which was identified as P. capsici. Chayote plants developed in growth chamber were inoculated with 1, 3 y 6 X 105 zoospores 15 days after sowing. Necrosis of the transition zone between the stem and roots, the percentage of wilted leaves and wilting of the plant were evaluated. Three days after inoculation (dai), 2.3 to 3.0 cm of necrosis length and 50 % of wilted leaves were observed. At five day, necrosis was 2.5 to 3.15 cm with 80 % of wilted leaves. At seven day, necrosis was 2.67 to 3.3 cm with 100 % wilted leaves (dead plant). Based on the observed symptoms, a severity scale was designed to evaluate the progression of damage P. capsici in chayote plants grown under controlled conditions.

Keywords : Inoculum level; Necrosis in the transitional zone between the stem and roots; leaf wilting.