Damping-off is considered one of the most limiting phytosanitary problems in conifer seedling production because it may cause massive damage or total plant death in short time periods. This pathology is caused by a complex of microorganisms, the most common of which are Fusarium spp. and Rhizoctonia spp. This study evaluated the effect of growth substrates and plant extracts at different concentrations on germination and incidence of disease in Pinus tecunumanii plants. The plants were inoculated with the damping-off pathogen Fusarium oxysporum and treatments were applied in a completely randomized design with a factorial arrangement of 4x2x3. This corresponded to four substrates (pine bark, rice hull, coconut husk and sandy soil (4:1)); two plant extracts (Matricaria chamomilla and Datura stramonium), and three concentrations of each extract (Control concentration: 0%, Concentration 1: 50 % and Concentration 2: Undiluted). Each treatment had three repetitions, with 25 plants per repetition. The growth substrates affected germination; the most effective of these were sandy soil (4:1) and pine bark, with 90% and 92% germination at day 20, respectively. No significant difference was observed between the germination obtained with these substrates and that obtained with coconut husk after day 19. Meanwhile, all of the extracts had a significant effect on controlling the disease when they were combined with the substrates, with the exception of coconut husk. With this last substrate the incidence of disease was lower than 4% without the application of plant extracts; this indicates that coconut husk discourages the development of the disease on its own. EFEITO DE EXTRATOS VEGETAIS E SUBSTRATOS DE PLANTIO NO CONTROLE DO TOMBAMENTO EM MUDAS DE Pinus tecunumaniiTombamento é considerado um dos mais limitantes problemas fitossanitários na produção de mudas de coníferas, pois pode causar grandes danos ou morte total da planta em curtos períodos de tempo. Esta patologia é causada por um complexo de microrganismos, os mais comuns são Fusarium spp. e Rhizoctonia spp. Este estudo avaliou o efeito de substratos de plantio e extratos vegetais em diferentes concentrações sobre a germinação e incidência da doença em mudas de Pinus tecunumanii. As mudas foram inoculadas com o fungo causador de tombamento Fusarium oxysporum e os tratamentos foram aplicados de forma totalmente casualizados com arranjo fatorial 4x2x3. O experimento foi composto por quatro substratos (casca de pinheiro, casca de arroz, casca de coco e solo arenoso (4:1)); dois extratos de plantas (Matricaria chamomilla e Datura stramonium) e três concentrações de cada extrato (Concentração testemunha: 0%, Concentração 1: 50% e Concentração 2: não diluído). Cada tratamento teve três repetições, com 25 plantas por repetição. Os substratos de plantio afetaram a germinação; o mais eficaz destes foi o solo arenoso (4:1) e casca de pinheiro, com 90% e 92% de germinação no dia 20, respectivamente. Não foi observada diferença significativa entre a germinação obtida c...