Spread of Piricularia Oryzae in Small Rice Fields from Foci of Different Sizes.

摘要

Race 1, isolate 429 of Piricularia oryzae was used to establish rice blast disease foci of 0.1-, and 0.0001-arce sizes in small fields of Gulfrose rice. Disease spread to the borders of the field with the largest focus within 14 days after inoculation, and to the borders of the field with smallest focus within 48 days. Measurements of leaf-disease increase, spore concentration in the air, per cent panicle blast, and yield were made at sampling stations in the foci and along polar coordinates radiating from them. (Author)