Aislamiento, caracterización cultural y morfológica de aislados monospóricos del agente causal del moho gris de la hoja de Solanum lycopersicum L. en la provincia de Tungurahua.

Abstract

The gray mold of the tomato leaf discovered in England in 1883 is characterized by producing yellow areas on the leaves, observing an olive green color on the underside, which affects the agricultural yield and the quality of the fruits. The objective of this work was to obtain monosporic isolates from tomato leaves with signs of gray mold in order to characterize them culturally and morphologically. For the monosporic isolation, the leaf printing method was obtained and later a modification of the Valmas method was obtained. For the cultural characterization of the colonies of the isolates, the following characteristics were evaluated: color of the front and back of the colonies, elevation, texture, edges, pigmentation and presence or absence of perspiration liquid. For the morphological characterization, the microculture method and observation under the microscope of the diameter of the hyphae, the length of the conidiophores and the length and width of the conidia were obtained. For the first time for Ecuador, 80 isolated monospores will be acquired from 8 cantons of the Tungurahua province (Tisaleo, Baños, Patate, Ambato, Cevallos, Píllaro, Mocha and Pelileo) all presenting olive green colors on the obverse of the colony, while in the reverse was black, in addition a superficial elevation, plush texture and irregular shape appeared. Isolates 1, 2, 3, 5, 6, 7, 8, 9, 10 had lobed borders in their colonies, while 5 showed regular borders. no pigment isolated from the culture medium (PDA), nor was there evidence of transpiration liquid in its colonies. The mycelial growth at 7 days was in a range between 0.50 mm.day -1 to 1.29 mm.day -1 , with the average speed being 0.93 mm.day-1 and at 14 days it reached values which were in the range between 0.95mm.day-1 to 1.46mm.day-1 , with the average velocity being 1.23mm.day-1 .The average diameter of the hyphae of the isolates obtained from C. fulvum showed a lower value of 2 µm, a higher value of 11 µm and an average value of 5.41 µm. In the conidiophores, the smallest size was 9 µm while the largest was 116 µm with an average value of 33.01 µm. The conidia regarding the length had a minimum value of 3 µm and the largest value of 13 µm with an average value of 6 µm, while the width of the conidia showed a minimum value of 1.5 µm and the maximum was 5 µm for an average value of 5 µm.