SELECTING AND PREPARING MATERIALS 



285 



not to displace the standard materials until new ones receive 

 the endorsement of his experiment station. 



b:8. Copper sulfate dust has been used in conjunction 

 with lime as a fungicide for apple sprays in Canada. Farther 

 south, severe burning has resulted. It is used extensively by 

 vegetable growers. 



(c) Consider Agents That Increase Spreading and Sticking 

 Qualities of Materials for Insect and Disease Control, Ma- 

 terials are sometimes introduced into the spray formula, not 

 because of their value as effective agents in themselves, but 

 because they affect favorably the physical properties of in- 

 secticides and fungicides. They increase the spreading quali- 

 ties of spray materials, giving greater uniformity in coverage, 

 or increase the adhesiveness or sticking qualities of the spray 

 materials, making them effective over longer periods. 



Various milk products have been used in recent years in 

 this connection. Casein is the effective agent in the milk 

 products. Although most experiment stations make favorable 

 reports on spreaders, some experimental results have shown 

 disagreement with these findings. In the meantime, growers 

 in general are not using these products extensively on account 

 of their cost and because they have felt that the benefits were 

 not very marked. Further tests and findings should be con- 

 sidered carefully. 



c : 1. Calcium caseinate contains about 20 per cent casein 

 and 80 per cent of hydrated lime. It is on the market under 

 various trade names, to be combined with lime-sulfur, Bor- 

 deaux, and arsenical sprays. Dilutions of 1 to 2 pounds per 

 100 gallons are recommended. 



c : 2. Skim milk has been used as a substitute for calcium 

 caseinate. General recommendations for all fruits indicate its 

 use at a rate of 1 gallon to 100 gallons of spray. 



c : 3. Flour, finely ground and of at least 12 per cent 

 gluten content, has given excellent results. Any standard 

 bread flour meets the requirements; pastry flours and the 

 coarse flours do not. Flour is entirely safe with all materials, 



