Previous View
APSnet Home
Phytopathology Home


Comparison of Blotters and Guaiacol Agar for Detection of Helminthosporium oryzae and Trichoconis padwickii in Rice Seeds. Martin M. Kulik, Research Plant Pathologist, Seed Quality Laboratory, AMRI, Agricultural Research Service, U. S. Department of Agriculture, Beltsville Agricultural Research Center-West, Beltsville, Maryland 20705; Phytopathology 65:1325-1326. DOI: 10.1094/Phyto-65-1325.

The blotter and guaiacol agar methods were compared for the detection of Helminthosporium oryzae and Trichoconis padwickii in rice seeds from 98 lots grown in the southeastern United States in 1972 and 1973. Correlation coefficients were 0.95 and 0.65 between the data from these two tests used to detect H. oryzae and T. padwickii, respectively. The guaiacol agar method appeared to be more sensitive than the blotter method for the detection of H. oryzae, and less sensitive for the detection of T. padwickii. The guaiacol agar method was much faster than the blotter method and did not require a microscope and “blacklight”-equipped incubator.

Additional keywords: brown leaf spot, stackburn disease, seed health testing.