The knowledge of the temporal pattern of rice pathogenic fungi dispersal, together with a correct examination of crops, can contribute to our understanding of disease distribution and management. Concentrations of Pyricularia grisea (Cooke) Sacc. and Bipolaris oryzae Shoem. airspores in a rice field located around Pavia (northern Italy) were estimated by using an automatic volumetric spore trap (VPPS Lanzoni). Measurements of their concentration were made between June and October over two years (1996 and 2001). Temperature, humidity, rainfall and fitness of the rice plants were monitored during the vegetative seasons. Peaks of P. grisea and B. oryzae airspores were always detected just 6-7 days before the onset of the typical symptoms of blast and brown spot. A significantly different spread of the two pathogens was detected as P. grisea spores always appeared later than B. oryzae ones. Peaks of B. oryzae spores were detected after a short rainy period, while the highest P. grisea spores concentrations were noticed when daytime temperature was about 24-27° for 4-5 days at least. P. grisea airspores concentrations/RH and P. grisea airspores concentrations/leaf wetness are correlations currently under analysis. Results confirm that there might be a correlation between spore release pattern and environmental conditions; we propose the aeromycological monitoring as an useful diagnostic method to forecast rice diseases.
AIRBORNE SPORES IN A RICE FIELD: PYRICULARIA GRISEA AND BIPOLARIS ORYZAE DETECTION.
PICCO, ANNA MARIA;RODOLFI, MARINELLA;LORENZI, ERIKA;RODINO, DORIANA
2002-01-01
Abstract
The knowledge of the temporal pattern of rice pathogenic fungi dispersal, together with a correct examination of crops, can contribute to our understanding of disease distribution and management. Concentrations of Pyricularia grisea (Cooke) Sacc. and Bipolaris oryzae Shoem. airspores in a rice field located around Pavia (northern Italy) were estimated by using an automatic volumetric spore trap (VPPS Lanzoni). Measurements of their concentration were made between June and October over two years (1996 and 2001). Temperature, humidity, rainfall and fitness of the rice plants were monitored during the vegetative seasons. Peaks of P. grisea and B. oryzae airspores were always detected just 6-7 days before the onset of the typical symptoms of blast and brown spot. A significantly different spread of the two pathogens was detected as P. grisea spores always appeared later than B. oryzae ones. Peaks of B. oryzae spores were detected after a short rainy period, while the highest P. grisea spores concentrations were noticed when daytime temperature was about 24-27° for 4-5 days at least. P. grisea airspores concentrations/RH and P. grisea airspores concentrations/leaf wetness are correlations currently under analysis. Results confirm that there might be a correlation between spore release pattern and environmental conditions; we propose the aeromycological monitoring as an useful diagnostic method to forecast rice diseases.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
