Fungicides 



205 



Fig. 47. A good rig for potatoes. 



discussed on page 120. It is important that the appa- 

 ratus have power. It should break up the spray and 

 should drive it into every nook and crevice of the 

 plant. On a pair of old wagon wheels an ingenious 



man can construct a 

 good platform for the 

 mounting of a spray- 

 ing rig. See Figs. 46, 

 47, 48. 



For plant diseases, 

 the staple fungicide is 

 Bordeaux mixture. 

 This is a preparation 

 of sulfate of copper 

 and lime, diluted with water. It is probable that the 

 lime has some slight fungicidal value, but its chief 

 merit is to make the material adhere to the foliage 

 and to neutralize the caustic effects of the sulfate of 

 copper. Bordeaux mixture may be applied with 

 advantage even before the disease appears, for it 

 adheres closely to the foliage and prevents the germi- 

 nationor, at least, the growth of the spores of the 

 fungi. If Bordeaux mixture is well made and well 

 applied, it will adhere to the foliage for some weeks, 

 particularly if it has time to set before rain falls. In 

 case of serious attacks, however, it is well to spray 

 every few days, because new shoots and new foliage are 

 constantly appearing; and it is practically impossible 

 in any one spraying to cover every part of the plant. 

 Bordeaux mixture is a blue whitewash; it discolors 

 the plants. If it is desired to have the foliage and 



