Relations of Intensity of Photosynthesis and Appearance of Piricularia oryzae Cav. on the Rice Plant

Abstract

Piricularia oryzae Cav. appears in the rice fields of Hungary in certain years, when a considerably decreased yield often occurs. However, appearance of the fungus did not cause a decrease of yield in every case. It was noted that the crop in some cases was not affected at all with the plants infected by Piricularia, whereas in other cases there was total damage in absence of the fungus. As a result of several years of experiment it may be stated that the fungus which, in the opinion of some workers, is the cause of browning disease (‘brusone’) appears only on certain soil-types. Results obtained so far of the investigation of browning disease suggest that the presence of fungi is rather a consequence of the effects and conditions of unfavourable soil and weather on the plant than connected with the browning disease proper.