Copper-Deficiency Disease of Apple Trees

Abstract

THE communication by Mr. J. O. Jones¹ dealing with the copper-deficiency disease of pear trees has tempted me to write briefly of my experience of the summer-spraying of apple trees in Northern Ireland with Bordeaux mixture. In the early nineteen-twenties, the 6,000 acres of apple orchards in the north of County Armagh and the south of County Antrim, which are mainly planted with the variety Bramley's Seedling, were in a very poor condition. The position was so serious that unless something could be done to restore the health of the trees, it looked as if the apple crop might become entirely unprofitable. Except for occasional winter-spraying with lime or caustic soda (tar-oil washes had only just been introduced) and the application of lead arsenate in summer to control caterpillar attack, no regular spraying programme was in operation and no suitable spraying machinery was available. Apple scab (Venturia inæqualis Aderh.) had just commenced to attack the variety Bramley's Seedling, and it was obvious that the control of this disease presented a major problem.