132 VEGETABLE FORCING 



portant fungicide for the treatment of vegetables grown 

 under glass. The chief objection to its use is the dis- 

 coloration of the fruits or products, and this is a serious 

 objection if the mixture is applied to the crops a short 

 time before they are to be marketed. The strength of the 

 proportions of the mixture may vary from two pounds of 

 copper sulphate and, two pounds of stone lime to 50 gal- 

 lons of water, to five pounds of copper sulphate and five 

 pounds of stone lime to 50 gallons of water. Ordinarily, 

 plants like the cucumber and tomato are not injured if 

 the 5-5-50 formula is employed. 



Various directions are given for making bordeaux mix- 

 ture, but a simple plan is to dissolve the copper sulphate 

 in a few gallons of hot water in a wooden pail. Slowly 

 slake the lime in another vessel and add enough water 

 to make a thick milk solution. The dissolved copper sul- 

 phate is then poured into the barrel or tank containing 

 about 40 gallons of water, the lime milk added and the 

 solution stirred. Additional water may be used if nec- 

 essary to make the total volume 50 gallons. Separate stock 

 solutions of copper sulphate and of lime milk may be 

 kept on hand, but the prepared mixture deteriorates when 

 left standing. It is important that unslaked stone lime 

 rather than air-slaked lime be employed. Air-slaking 

 may be prevented by keeping the stone lime in tightly 

 covered vessels. The Ohio Station reports that bordeaux 

 mixture is most effective when the atmosphere of the 

 house is so highly humid that the leaf surfaces are moist. 



Ammoniacal copper carbonate. As previously indi- 

 cated, bordeaux mixture leaves a deposit on the plants 

 and fruits which is objectionable if the products are soon 

 to be marketed. For this reason, some growers prefer to 

 use ammoniacal copper carbonate which leaves only a 

 slight deposit previous to harvesting and marketing 

 certain crops, though this fungicide is not so effective as 

 bordeaux mixture. The mixture contains the following 

 constituents : 



