MERCURY RESIDUES ON APPLE FRUIT AND FOLIAGE

Abstract

The disappearance of mercury from apple foliage and fruit sprayed with organo-mercury fungicides was investigated.Most of the initial foliage deposit soon became water insoluble and spore germination tests on the surface of leaves demonstrated a rapid decline in fungitoxicity. The total amount of mercury on the foliage decreased rapidly in the first 2 weeks after spraying and more gradually in the succeeding 2 months.The application of pre-cover sprays resulted in negligible fruit residues. The average harvest residue of fruit receiving an early cover spray was 0.05 p.p.m., of which the peel, pulp and seeds contained about 41, 57 and 2 per cent, respectively. There were no significant differences between residues in fruit sprayed on different dates.