A standard technique for detecting seed transmitted Phomopsis leptostromiformis of lupins and for testing commercial seed in South Australia

Abstract

A standard agar plate method was tested for its ability to detect Phomopsis leptostromiformis on lupin seed. It proved to be reliable. The 95% confidence intervals of Phomopsis level of five seed samples were 13.2-1 5.8, 13.2-1 5.5, 15.4-1 7.9, 13.2-1 4.8 and 15.6-1 8.0. The characteristic colony produced by Phomopsis infected seeds on agar media was confirmed by microscopic examination for accuracy of detection and no exception was observed. The method is described in detail. The method was then used in a two year survey of 160 samples of commercial lupin seed from all parts of South Australia. The percentage of seed infected in these samples ranged from 0-20% and only 13% of the samples were free of P. leptostromiformis.