Most of the nurseries use rigid plastic containers and mainly peat moss, perlite, and vermiculite, a mixture known as standard mixture or base mixture, as the environment where plants are grown ( Sánchez-Córdoba et al., 2008). Late damage occurs during the plant’s development, mainly when the stems have not yet achieved the hardening stage, causing the root to rot and the seedling to fold it can be observed as reddish needles and brown roots ( Peterson, 2008 Solano and Brenes, 2012). It appears during the pre-emergence stage -when the fungus damages the embryo before it germinates, resulting in hypocotyl and cotyledon necrosis- and during the post-emergence stage-when the fungus strangles the stem, at ground level, and kills the plant. It diminishes the quality of the plant, causing the production to drop by up to 40 % ( Cibrián et al., 2008). The drying disease that affects pines in Mexican nurseries is mainly caused by Fusarium species. The drying disease is produced by a soil fungi complex that includes: Pythium spp., Phytophthora spp., Rhizoctonia spp., Botrytis spp., and Fusarium spp.
The main phytosanitary problem faced by nurseries is a disease known as the damping-off complex, nursery disease, drying disease, stem disease, choke disease, strangulation, and root rot. The Comisión Nacional Forestal (CONAFOR), the institution in charge of Mexican forests, will restore a million hectares from 2013 to 2018, reforesting 180 million plants, in the temperate-cold, tropical, and arid-semiarid ecosystems ( CONAFOR, 2015). An important part of the plant production process takes place in the nurseries therefore, the quality and health of the trees must be guaranteed, before they are planted ( Solano and Brenes, 2012). In Mexico, the Pinus genus includes the species that are most frequently used in forest nurseries in temperate zones to produce plants for reforestation purposes. Palabras claves: viveros incidencia turba de musgo corteza de pino y aserrín La incidencia de la enfermedad fue menor en S2, en los primeros dos meses y su patogenicidad en post-emergencia se comprobó con la inducción de síntomas y reaislamientos de F. El hongo redujo significativamente la germinación de semillas de P. El análisis estadístico del porcentaje de germinación se realizó con ANDEVA y la comparación de medias con la prueba de Duncan (p≤0.05). El diseño experimental fue completamente al azar, con seis tratamientos y cuatro repeticiones cada uno. Los sustratos fueron turba de musgo, perlita y vermiculita (S1), aserrín, corteza y turba de musgo (S2) y corteza, aserrín y turba de musgo (S3) y se evaluaron en proporciones de 60:20:20. se aisló de plántulas enfermas, se purificó e identificó por su morfología y molecularmente como F. Los objetivos de este estudio fueron identificar morfológica y molecularmente la especie de Fusarium que afecta al vivero de Atlangatepec, Tlaxcala, que causa secadera y pudrición de raíz en Pinus greggii Engelm., evaluar su efecto en la germinación de semillas en tres sustratos y analizar la incidencia y patogenicidad en plántulas en desarrollo. La enfermedad de la secadera afecta en pre-emergencia, post-emergencia y causa constricción del tallo y pudrición de la raíz en plantas desarrolladas en viveros forestales.
Key words: nurseries incidence peat moss pine bark and sawdust Disease incidence was lower in S2, during the first two months, and its post-emergence pathogenicity was proved by the induction of symptoms and reisolations of F. The fungus produced a significant reduction in the germination of P. The statistical analysis of the germination percentage was executed with ANOVA and the means comparison was carried out using the Duncan test (p≤0.05). The experiment had a completely randomized design, with six treatments and four repetitions per each one. The substrates were: peat moss, perlite, and vermiculite (S1) sawdust, bark, and peat moss (S2) and bark, sawdust, and peat moss (S3) they were evaluated in 60:20:20 ratios. The Fusarium fungus was isolated from diseased seedlings, it was purified, and, based on its morphology and molecular structure, as identified as F. The objectives of this study were to identify the morphological and molecular characteristics of the Fusarium species that affects the nursery located in Atlangatepec, Tlaxcala, which causes the drying disease and root rot of Pinus greggii Engelm., to evaluate its effect in the germination of seeds in three substrates, and to analyse the incidence and pathogenicity of developing seedlings.
The drying disease affects plants grown in forest nurseries during the pre-emergence and post-emergence stages, constricting the stem and causing root rot.