Methods of Control 367 



Copper carbonate 5 ounces 



Ammonia (26 Baume) 3 pints 



Water . 50 gallons 



The best results are obtained when the copper car- 

 bonate is first made into a paste with a little water. 

 It is then dissolved by adding the ammonia, which is 

 diluted with four quarts of water. If three pints 

 of ammonia fail to dissolve all the copper carbonate, 

 more may be used. Ammoniacal copper carbonate 

 is only effective when used fresh. It loses its fungi- 

 cidal value by standing, as the ammonia evaporates 

 quickly. 



(c) Sulphur. Flowers of sulphur are often used to 

 control powdery mildew or asparagus rust. It may 

 be applied either by hand or with a duster. There 

 are a number of other fungicides on the market which 

 are not mentioned here. They should be thoroughly 

 tested before they are used. Considerable discretion 

 should be exercised before using a new fungicide 

 which claims to be a ' ' Cure all. " 



COMBINATION SPRAYS 



In the foregoing chapters on diseases, it was seen 

 that truck crops are subject to the attacks of more 

 than one malady. Moreover, truck crops are also 

 subject to the attacks of insect pests. It is therefore 

 advisable to control both insect pests and fungous 

 diseases at the same time. Spraying, if properly 



