When to Spray 333 



closely, and spray when he needs to do so, or when he is 

 in doubt. Two sprayings are sufficient for the codlin- 

 moth, and three are usually sufficient for the apple-scab. 

 These two sprayings constitute the insurance that has 

 been mentioned; thereafter, the grower will be able to see 

 more definitely what is needed. These remarks illustrate 

 the nature of the questions that the fruit-grower must 

 consider. 



9. Keep posted. Every year, read the new bulletins, 

 note the articles in the agricultural papers, keep in touch 

 with the discussions before societies, secure the publica- 

 tions of manufacturers. The practice in spraying is mov- 

 ing rapidly, and new studies of insects and diseases are 

 constantly being made. The practices are now well stan- 

 dardized, but modifications are often made and new pests 

 appear. The grower must be vigilant. 



LISTS AND FORMULAS 



The marked departures in spraying in recent years 

 have been not only in the perfecting of the mechanical 

 devices, but in the character of the spray materials. Lon- 

 don purple and paris green are now little used, and arsen- 

 ate of lead and arsenate of lime have taken their places. 

 Bordeaux mixture is still the standard fungicide for plants 

 in a growing condition, although lime-sulfur is now mostly 

 used for summer spraying of apples and pears, as well as 

 for the winter spraying. On most plants, lime-sulfur 

 has a serious dwarfing effect on foliage. Bordeaux is used 

 for grapes, small-fruits, potatoes and many other things. 

 Arsenate of lead may be combined with lime-sulfur as 

 well as with bordeaux. 



