**Acknowledgements**

*Multifunctionality and Impacts of Organic and Conventional Agriculture*

therefore, fungus can also be favoured with a HOM treatment.

eco-friendly tools to substitute the use of agrochemicals.

The attained results revealed that the HOM treatments showed activity against *F. oxysporum*, highlighting *Zincum phosphoricum* and *Magnesium phosphoricum*. These cause-effect results in the plant model demonstrated that a placebo effect is not only absent in homoeopathic medicine but also supports agricultural homoeopathy. These results contribute to search for alternatives to control diseases caused by this phytopathogen in tomato plants, by using effective, innocuous and more

A lot of experimental scientific results related with the use of homoeopathic medicines in plants, besides new results and insights discussed along this chapter, eliminate the principal argument of homoeopathy detractors. Actually, they cannot sustain their arguments in the sense that the suggestion and the placebo effect are the only mechanisms of action of this old, and at the same time new, alternative for organic agriculture.

soil layer and death of microorganisms in soil. Additionally, the pathogens have developed resistance to the active ingredient of the agrochemical that generally has a high cost [34]. Therefore, it is necessary to search for ecological and less polluting alternatives for the control of pests and diseases in agriculture, ensuring the safety and future of the agro-food industry. The objective of this study was to evaluate the in vitro effect of homoeopathic medicines on the pathogenic fungus *Fusarium oxysporum* f. sp. lycopersici, highly damaging various agricultural crops [66]. An experimental design which is completely randomised was applied with six homoeopathic medicines, each in two dynamisations (7 CH and 13 CH, Similia® CDMX, Mexico): T1 (MaP 7CH), T2 (ZiP 7CH), T3 (PhA 7CH), T4 (SiT 7CH), T5 (NaM 7CH), T6 (ArA 7CH), T7 (MaP 13CH), T8 (ZiP 13CH), T9 (PhA 13CH), T10 (SiT 13CH), T11 (NaM 13CH) and T12 (ArA 13CH) and one control (DW) to measure antifungal activity against *F. oxysporum*, using the method of the poisoned medium [67]. The diameter of the mycelium was measured daily, and the percentage of growth inhibition was determined by the formula [%inhibition = mycelial growth of the control − mycelial growth of the treatment/mycelial growth of the control × 100]. No significant differences were observed in radial growth of the phytopathogenic fungus in the HOM treatments with respect to the untreated control (NT). On the other hand, significant differences were observed between HOM treatments and their dynamisations (7 CH and 13 CH) with respect to NT. The dynamisation 13 CH increased the percentage of inhibition of the phytopathogenic fungus. These results confirmed the variability of the response induced by homoeopathic medicines in plant model, whose response depends on the dynamisation used [68]. These results are in agreement with those reported by Narváez-Martínez et al. [28] who used a homoeopathic treatment developed from a pathogen (nosode); when they applied different dynamics in tomato *Solanum quitoense* Lam, they found different effects against a pest caused by *Neoleucinodes elegantalis*. HOM treatments T2, T7 and T12 offered a greater inhibition percentage against the pathogen (70, 65 and 51%, respectively). These results agree with Tichavsky [69], who stated that *Phosphorus* homoeopathic medicine helped to control diseases caused by fungi, and two of these treatments contained phosphorus. According to Casali et al. [70], this result was due to the production of secondary metabolites (essential oils). However, during this study, HOM treatments T3 and T9 favoured the growth and reproduction of the fungus. Our results coincide with Damin et al. [71] who evaluated nine homoeopathic medicines against the pathogen *Metarhizium anisopliae* and obtained stimulation in the production of conidia by this fungus. It is necessary to conceptualise that homoeopathy acts on living beings;

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**3. Conclusions**

This study was financed by the Sectorial Fund for Education of Mexico: Project CB SEP-CONACYT-258282 'Experimental evaluation of homoeopathy and new probiotics in the culture of molluscs, crustaceans and fish of commercial interest' and Project PROINNOVA-CONACYT-241777 'Innovation and continuous improvement of products and processes to optimise hatchery seed production of the American oyster *C. virginica*', under academic responsibility of the first author (JMMS); the authors thank Diana Fischer for editorial services.
