VIEW ARTICLE

Influence of Planting Media and Soil Sterilization on the Uptake of Benomyl by American Elm Seedlings. L. R. Schreiber, Plant Pathologist, Plant Science Research Division, ARS, USDA, Delaware, Ohio 43015; W. K. Hock(2), and B. R. Roberts(3). (2)(3)Plant Pathologist, and Plant Physiologist, respectively, Plant Science Research Division, ARS, USDA, Delaware, Ohio 43015. Phytopathology 61:1512-1515. Accepted for publication 27 July 1971. DOI: 10.1094/Phyto-61-1512.

Benomyl fungicide was applied to 6-month-old American elm seedlings grown in sand, soil, or a mix of soil:peat:perlite (1:2:2). Zones of inhibition, around tissue sections from treated plants placed on petri plates with potato-dextrose agar seeded with Ceratocystis ulmi conidia, were indicative of the relative concentration of fungitoxicant in the plants. The most fungitoxicant accumulated in plants grown in sand, and the least, in those grown in the mix when bioassayed 5, 30, 60, and 90 days after treatment. The planting medium affected the total amount as well as the rate of accumulation of the fungitoxicant. Highest levels of accumulation of the fungitoxicant were in seedlings grown in media with the lowest content of organic matter and the highest pH. No direct correlation existed between benomyl uptake and the growth in height of the plants. Heat sterilization of soil, prior to benomyl treatment and planting elm seeds, resulted in increases in the accumulation of fungitoxicant in plants compared to those grown in nonsterile soil.