404 Diseases of Greenhouse Crops 



The best results are obtained when the copper 

 carbonate 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 cop- 

 per carbonate, more may be used. Ammoniacal cop- 

 per carbonate is only effective when used fresh. It 

 loses its fungicidal value by standing, as the am- 

 monia evaporates quickly. 



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. 



Combination Sprays. For purposes of economy, 

 it is advisable to control both insect pests and fun- 

 gous diseases at the same time. Spraying, if prop- 

 erly done, is effective in controlling or in keeping 

 in check all the pests which attack greenhouse crops. 

 In combining a fungicide with an insecticide, we 

 may accomplish two aims in one operation. The 

 various spray mixtures which may or may not be 

 combined are indicated by Cooley and Swingle * — 



Bordeaux 

 Mixture 



Paris green yes yes 



Arsenate of lead yes yes 



Arsenite of zinc (ortho) yes no 



Arsaoite of lime yes yes 



* Cooley, B. A., and Swingle, D. B., Montana Agr. Expt Sta. 

 Circ. 17: 1x9-151, 1912. 



