Controllo dei patogeni del riso trasmissibili per seme.

Control of seed-trasmitted pathogens of rice. Studieson the effect of rice seed treatments for the control of Bipolaris oryzae were carried out by using biological and chemical formulates. In particular, greenhouse experiments were performed to verify the efficacy of seed treatments against the inoculum localized in the seed and in the soil. The phytosanitary tests showed that B. oryzae can be frequently found in rice seeds. Seed tratments for the control of this pathogen did not give satisfactory results when they were applied to infected seeds. Conversely, all the formulatios applied to healthy seeds protectd the seedlings from infections caused by the inoculum located in the soil. This indicated that, under our experimental conditions, it was not possible to control B. oryzae by seed treatments when the inoculum was lcated deeply in the seed. Since the control of B. oryzae is very difficult, the best strategy is represented by the use of healthy seed. This could be achieved by performing careful monitoring of the phytosanitary state of rice seed crops in order to promptly and rationally protect them at the first occurrence or the disease. Moreover, seed crops should be established in areas where the environmental conditions usually restrict the development of parasites and their subsequent localization in the seed. In addition, seed lots with high levels of infection could be identified and eliminated trough the phytosanitary analysis of the seed. In the future, research will have to focus on the study of alternative control methods compatoble with organic farming , especially those involving the use of physical menas for inoculum devitalization, without altering seed viability.