Pest and Disease Management of Potato Crops with Homeopathic Preparations and Germplasm Variability

Summary

The Plateau of Santa Catarina state, Brazil, is the main potato seed producer of the country. Its regional climate, however, with wet summers has been pointed out as the main factor for restricting productive quality and raising prices. This research had, thus, the objective of studying the efficacy of homeopathic preparations, homemade formulations and genetic variability in the management of pests and diseases at field conditions on organic farming systems of potato crops. Two field experiments were installed during the 2006/07 crop season. In experiment 1, the following genotypes were planted as treatments: Catucha and Epagri (landrace), Monalisa and Agata (Holland), and Panda (Germany). In experiment 2, the statistical design was a split plot with the Monalisa, Catucha and Epagri genotypes as sub plots, and nine spray preparations as the main plot as follows: Chamomilla 60CH, Silicea 60CH, Kali 60CH, Thuya 60CH, biotherapic of Phytophthora infestans 60CH, water 60CH, the homemade preparations of Bordeaux mixture at 0,3% and of propolis extract at 0,5%, and, finally, a no-intervention treatment. Results showed that the Catucha genotype, a bred landrace, yielded 21 t ha-1 and presented the lowest disease incidence. Even though no preparation differed significantly from another; the Thuya homeopathic treatment yielded the best results with more than 26 t ha-1. Natural enemies were not affected by any of the spray preparations.