SPRAYING AND SPRAYING MATERIALS. 153 



SPRAYING AND SPRAYING MATERIALS. 



R. S. MACKINTOSH, ASST. HORTICULTURIST, MINN. AGRI. EXPERIMENT 



STATION. 



The spraying calendar is only a reminder of what is to be done 

 if the plants are in danger of being attacked by insects or fungous 

 diseases. 



Poisons like Paris green, London purple, etc., kill only when 

 taken internally by the insects; hence are of no use. in destroying 

 "sucking" insects, as plant lice. Kerosene emulsion, or kerosene 

 and water, are used for soft-bodied insects, as plant lice, and kill by 

 contact. Copper sulphate is used to prevent the spores of fungous 

 diseases from growing on the surface of plants. It is dangerous to 

 apply it when plants are in leaf; hence it is mentioned in the cal- 

 endar to be used only before the buds start in the spring. Bor- 

 deaux mixture is made of copper sulphate (blue stone) with lime 

 added to prevent the copper sulphate from injuring the foliage. 

 It is useful only when applied in time to prevent the spores of the 

 fungous disease from growing. It is necessary then to keep the 

 foliage and stems covered with the Bordeaux mixture during the 

 time the spores are spreading. 



The materials should be applied in as fine a spray as possible. 

 To do this a good strong force pump is necessary, and a simple 

 nozzle that will break up the solution into a mist-like spray, and 

 hose and piping to carry the material easily to all parts of the tree. 

 Do not try to work with only a short length of hose — the work 

 cannot be done well enough, and if not done well it is time and 

 money wasted. The pump should have a brass lined cylinder, and 

 it is preferable to have one that has the cylinder in the liquid, as in 

 the barrel, and also arranged so that it can be quickly taken out to 

 be repaired when necessary. 



An agitator to keep the mixtures mixed properly is very essen- 

 tial. 



Bordeaux Mixture. — Copper sulphate (blue vitriol), 5 lbs.; quick 

 lime, 5 lbs.; water, 50 gallons. 



Dissolve the copper sulphate in a wooden or earthen vessel, 

 either by suspending it in a sack near the surface of the water or 

 by using hot water. When dissolved, dilute with fifteen gallons of 

 water. The lime should be of best quality, free from grit and 

 not air slaked. Slake it with hot water by adding enough water to 

 keep it from burning. Dilute with fifteen gallons of water. When 

 ready to use, pour the two solutions together through a wire 



