Trichoderma afroharzianum and homeopathic substances on the in vitro growth of fungi associated with fungal diseases

Background/Objective. Trichoderma spp. is a sustainable alternative, as well as some homeopathic substances that are emerging as potential antifungal agents; making them promising solutions for combating and controlling diseases in crops of economic importance. The objective of the study was to evaluate the antagonism of Trichoderma afroharzianum and homeopathic substances against four fungi responsible for diseases of horticultural importance. Materials and Methods. The antagonism of T. afroharzianum against Phytophthora capsici, Rhizoctonia solani, Botrytis cinerea, and Fusarium oxysporum was evaluated using the dual culture technique. The percentage of inhibition was estimated every 24 hours by measuring mycelial growth and type of antagonism. Homeopathic substances derived from essential oil of Tagetes remotiflora, Tagetes arenicola, and Tagetes lucida were evaluated using the poisoned agar technique on all organisms. A completely randomized design with four replicates was used. The data were analyzed using Tukey's mean comparison test (p ≤ 0.05). Results. T. afroharzianum inhibited over 50% of the fungi and stopped their growth in all cases. Only in the interaction between P. capsici and T. afroharzianum did the antagonist grow over P. capsici and deform the hyphae. Homeopathic oil of T. remotiflora in 6CH dinamization reduced the growth of R. solani (21.95 vs 25.38 mm in the control), F. oxysporum (18.52 vs 21.35 mm in the control), and T. afroharzianum (20.87 vs 22.86 mm in the control), while 200CH dinamization of T. arenicola stimulated the growth of T. afroharzianum (25.15 vs 22.86 mm in the control), P. capsici (23.85 vs 16.18 mm in the control) and B. cinerea (25.98 vs 18.48 mm in the control). Conclusion. T. afroharzianum showed a greater ability to counteract the growth of P. capsici and B. cinerea. Homeopathic substances may have applications as inhibitors and stimulators of mycelial growth; further research is needed to better guide their applications.