Aislamiento y caracterización del agente causal del manchado de la hoja y necrosis del fruto de Capsicum annuum L. en cinco localidades de la Provincia de Tungurahua y una localidad de la provincia de Chimborazo

Abstract

Leaf spotting and fruit necrosis caused by C. fulvum causes chlorotic spots on the upper side of the leaves that turn yellowish as the pathogen progresses and dark spots on the underside that turn olive green, causing partial or total loss of leaves and exposing the fruit to direct sunburn. The fruit shows tan to black lesions that, as the pathogen progresses, form a kind of olive-green velvety mass, causing great economic problems for growers. The objective of this research is to obtain monosporic isolates of the causal agent of leaf spot and fruit necrosis, the characterization of the colonies, the description of morphological characteristics, the inoculation of healthy leaves and fruits, where 106 solutions were made and finally the reisolation from inoculated leaves and fruits. Six monosporic isolates obtained from leaves and six monosporic isolates obtained from fruits were obtained from five localities in the province of Tungurahua (Ambato, Baños, Patate, Pelileo and Mocha) and one locality in the province of Chimborazo (Riobamba), each isolate presenting different characteristics in both leaf and fruit. The morphological characteristics of isolates of C. fulvum showed an average hyphal size of 93.67 µm in isolates obtained from leaves and an average of 99.18 µm in isolates obtained from fruits. The conidiophores with average length of 27.82 µm in isolates from leaves and average of 25.82 µm in isolates from fruits. In conidiophores with average length of 5.11 µm and average width of 3.67 µm in leaf isolates and average length of 5.8 µm and average width of 4.03 µm in fruit isolates. In the inoculation of healthy leaves and fruits, the infection rate was determined in (%) as the first symptoms appear and as the days go by, the leaves and fruits become more contaminated and obtain a higher infection percentage. In the re-isolation, the same colonies of C. fulvum were obtained in leaves and fruits that were harvested at the beginning of the research.