Plant Sanitation. 



512 



[December, 1911. 



Dissolve the soap in water and add 

 the crude carbolic acid, then add suffi- 

 cient water to make 2 quarts. This 

 should be used as a stock solution, using 

 1 pint of stock to 6 gallons of water. 



Bordeaux Mixture. 

 Bordeaux mixture is used in combin- 

 ation with arsenate of lead. In this 

 way two sprays are applied at once— a 

 stomach poison and a fungicide. This 

 is far more economical and frilly as 

 good results are obtained as when the 

 two sprays are used separately. The 

 formula for Bordeaux mixture is as 

 follows : — 



Copper sulphate ... pounds 4 

 Quicklime ... ... ,, 6 



Water ... ... gallons 50 



Dissolve the copper sulphate in 25 

 gallons of water. This is very easily 

 done by putting the copper sulphate 

 in a bag which is suspended by a rope 

 in a barrel ; this enables one to deter- 

 mine if all the sulphate is dissolved. 

 Slake the lime in a small amount of 

 water, then add sufficient water to 

 make 25 gallons. The two ingredients, 

 copper sulphate aud lime, may be used 

 as a stock solution. For making Bor- 

 deaux, use equal parts of the two, 

 pouring them into the spray tank at 

 the same time. 



Wooden vessels should be used for 

 the mixing of the above, as Bordeaux 

 mixture corrodes iron. 



Stock solutions of Bordeaux mixture 

 maybe made by slaking 50 pounds of 

 lime in a barrel and adding sufficient 

 water, to make 25 gallons ; then for each 

 barrel of spray use 3 gallons of the lime 

 mixture. In the same way dissolve 50 

 pounds copper sulphate in 25 gallons of 

 water and use for each barrel of 

 Bordeaux 2 gallons of this solution. To 

 obtain the best results each of these 

 solutions should be prepared separately 

 with 25 gallons of water and then 

 combined. 



In spraying with Bordeaux mixture a 

 pump with a good agitator is necessary, 

 as the precipitate, which is a chemical 

 union of the lime and copper has a ten- 

 dency to settle. All parts of the pump 

 should be made of brass, not iron. 



Hints on Purchase op Ingredients. 



Extreme care should be used in pur- 

 chasing the ingredients for the soap and 

 for the stock emulsions. There are a 

 number of different grades of the various 

 ingredients on the market, but from 

 experience at this station and in the 

 United States it is best to obtain the 

 ingredients direct from large , dealers 



and according to exact specifications. 

 The following specifications and prices 

 are quoted by New York firms : — 



Pure menhaden, or fish oil, in barrel 

 lots costs from 30 to 37 cents per gallon. 



Caustic potash, 92 per cent, ground, 

 can he purchased at 8 to 9 cents per 

 pound by the hundredweight. 



There are a number of grades of 

 earbolic acid on the market which range 

 from 20 to 100 per cent. The lower 

 grades are not suitable for making the 

 soap as they have a tendency to produce 

 thick soaps, which do not emulsify the 

 oils. The high-grade 100 per cent, crude 

 carbolic acid, of straw colour, can be 

 obtained for 40 to 45 cents per gallon in 

 barrel lots. A 100 per cent, crude carbolic 

 acid, dark, has also been obtained, which 

 has given equally good results. This 

 costs a few cents less per gallon than the 

 straw colour. 



Rosin oil is a vegetable oil obtained 

 from the turpentine distilleries and 

 costs from 23 to 26 cents per gallon in 

 barrel lots. 



Summary. 



The present condition of the citrus 

 industry in Porto Rico is very promising. 

 No insects are found in the groves that 

 cannot be held in cheek by thorough 

 treatment. 



For biting insects, arsenate of lead is 

 the best spray for the conditions that 

 eixst on the island. Paris green does 

 not have the adhesive power of the 

 arsenate of lead. 



Sprays containing oils are used for 

 scale insects, but they will also keep the 

 rust mite and red spider in check. 

 However, where spraying is being done 

 for the rust mite and red spider alone, 

 it would be betterto use sulphur sprays. 



The purple scale has been the worst 

 enemy, but since windbreaks have been 

 introduced, the beneficial fungi play a 

 very important part in checking it. 



The hemispherical scale and the 

 Florida red scale are both held in check 

 by the sprays used for the purple and 

 white scales, and so is the white fly. It 

 is very seldom that these insects need 

 special treatment. 



It is considered advisable to pick all 

 the fruit before the new blossom growth 

 starts, so that the sprayers may clean 

 the trees well for the new crop. If the 

 trees are thoroughly cleaned in this 

 way, there is very little chance for the 

 fruit to become scaly. 



A great deal of the cultivated fruit 

 has been disfigured either by fungi, 

 mechanical bruises, or by insects. 

 Special attention is called to the' last 



