A Quantitative Inoculator Capable of Inoculating Cereal Plants at All Growth Stages with Rust Urediniospores. S. L. FOX, Research Associate, Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul 55108. D. E. HARDER, Plant Pathologist, Agriculture and Agri-Food Canada Research Centre, 195 Dafoe Road, Winnipeg, MB, R3T 2M9. Plant Dis. 79:391-394. Accepted for publication 3 October 1994. Copyright 1995 Department of Agriculture and Agri-Food, Government of Canada. DOI: 10.1094/PD-79-0391.

An inoculator, designed to quantitatively apply a spore/oil mixture on single stems or leaves of cereal plants, was constructed and tested. The tests consisted of counting urediniospores of Puccinia graminis f. sp. tritici applied to a glass slide, or counting uredinia that formed on seedling leaves and adult plant stems of susceptible or several different resistant genotypes of Hordeum vulgare, or susceptible Triticum aestivum. Using 2-mg spores suspended in l mL of light mineral oil, urediniospores were applied to glass slides at the rate of 125-224 spores/ cm2, with coefficients of variation between 7 and 22. In plant tests, distinctions between resistant and susceptible genotypes could be made using quantitative inoculations, when qualitative differences were not detectable.

Keyword(s): barley, inoculation technique, stem rust, wheat