Use of homeopathic preparations in phytopathological models and in field trials: a critical review.

BACKGROUND The literature on the applications of homeopathy for controlling plant diseases in both plant pathological models and field trials was first reviewed by Scofield in 1984. No other review on homeopathy in plant pathology has been published since, though much new research has subsequently been carried out using more advanced methods. OBJECTIVES To conduct an up-to-date review of the existing literature on basic research in homeopathy using phytopathological models and experiments in the field. METHODS A literature search was carried out on publications from 1969 to 2009, for papers that reported experiments on homeopathy using phytopathological models (in vitro and in planta) and field trials. The selected papers were summarized and analysed on the basis of a Manuscript Information Score (MIS) to identify those that provided sufficient information for proper interpretation (MIS>or=5). These were then evaluated using a Study Methods Evaluation Procedure (SMEP). RESULTS A total of 44 publications on phytopathological models were identified: 19 papers with statistics, 6 studies with MIS>or=5. Publications on field were 9, 6 with MIS>or=5. In general, significant and reproducible effects with decimal and centesimal potencies were found, including dilution levels beyond the Avogadro's number. CONCLUSIONS The prospects for homeopathic treatments in agriculture are promising, but much more experimentation is needed, especially at a field level, and on potentisation techniques, effective potency levels and conditions for reproducibility. Phytopathological models may also develop into useful tools to answer pharmaceutical questions.