230 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



WINTER WASHES TRIED AT WISLEY, 1914-15. 



By Professor H. M. Lefroy, M.A., Entomologist. 



The points tested in this trial of winter washes for fruit trees 

 were : — 



1. Solubility in, or miscibility with water. 



2. Corrosiveness (ease of spraying). 



3. Effect on workers or their clothes. 



4. Wetting power. 



5. Cost. 



6. Effectiveness. 



The conditions under which the washes were tried are set forth 

 below. 



The following notes will make clear the meaning of the six points 

 referred to. 



1. The washes were made up with cold water in the manner 

 recommended by the makers. As all mixed freely this point is not 

 further considered, but it was noted that some required more prepara- 

 tion than the simple mixing of a wash with water ; this is regarded 

 as a disadvantage, as more skill and care are required to make and 

 mix two solutions than to make one, and there is greater risk of a 

 mistake being made. 



2. Corrosiveness refers particularly to risk of injury to machines 

 rubber tubing. Some sulphur compounds attack copper or brass ; 

 some caustic solutions loosen rubber tube connexions ; some paraffin 

 washes attack rubber. It is an advantage if the wash has none of 

 these characteristics. 



3. Some winter washes are so caustic that the workers must wear 

 goggles, rubber gloves, and waterproof overalls ; this is a disadvan- 

 tage. So too is a wash that is markedly poisonous, though this is 

 an unusual feature. 



4. Wetting power. No wash with very deficient wetting power 

 would be likely to succeed ; the point was noted by eye only, and 

 not much importance is attached to it. Good wetting power means 

 economy, less wash being used. 



5. Cost. It is possible to get absolutely effective washes easily if 

 the consideration of cost is eliminated. One of the most effective that 

 happens to have been used (not in the trial, but experimentally) costs 

 £75 for 100 gallons. This is, of course, ridiculous, but it shows that 

 the cost must be kept in view. In estimating cost there is this point : 

 a wash selling at a certain price for a single gallon tin through a 



