QUANTIFICATION OF ENDOSPORE CONCENTRATIONS OF PASTEURIA-PENETRANS IN TOMATO ROOT MATERIAL

Six methods for quantification of the endospore concentrations of Past euria penetrans from tomato roots are described. Mortar disruption and machine disruption methods gave the highest estimations (endospores p er gram of root material) of 83.7 and 79.0 million, respectively. Thes e methods were significantly superior to incubation bioassay (47.7 mil lion), enzymatic disruption (32.1 million), and enzymatic disruption flotation (25.8 million) methods. A centrifugation bioassay method ga ve the lowest estimation of 12.7 million.