This section is from the book "Commercial Gardening Vol3", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
Where disease has previously existed it is often advisable to spray during the winter months, when vegetation is in a dormant condition. Under such circumstances a much stronger solution can be used without risk. The Woburn Winter Wash (B) is perhaps the best all-round winter wash to use, as it destroys all moss and lichens, thus removing the shelter required by numerous insects; it also kills the mussel and oyster-shell bark lice, in addition to destroying the spores of the Apple-scab fungus present on dead branches.
Its composition is as follows: -
Sulphate of copper (Milestone) ... 1 1/2 lb.
Lime ... ... ... ... ... 1/2 „
Paraffin... ... ... ... ... 5 pt.
Caustic soda ... ... ... ... 2 lb.
Water............... 10 gall.
Dissolve the bluestone in a few gallons of water; slake the lime in water and add to the dissolved bluestone, straining it to remove all grit; then add the paraffin and stir thoroughly. Finally add the caustic soda dissolved, along with water to make up 10 gall.
The trees should be thoroughly drenched. The ground may also be treated with advantage.
It is most important to remember that the above wash should only be used during the winter months, before the buds commence to swell.