226 VEGETABLE FOES AND DISEASES 



the plants in the stems and roots, and is an excellent 

 fertiliser. The dressing requires to be repeated at 

 intervals of a fortnight or three weeks, scattering the 

 mixture over the plants whilst the leafage is wet with 

 dew. 



3. Spraying the plants with a mixture of paraffin 

 oil, soft soap and water, at the rate of a quart of 

 paraffin and half a pound of soap to ten gallons of 

 water, has been found effective in preventing attacks 

 of the fly. This paraffin oil and soft soap must be 

 thoroughly incorporated in a small quantity (eight times 

 that of soft soap) of boiling water, churning for five 

 minutes with a small hand syringe to form a perfect 

 emulsion, and then dilute to ten gallons, applying 

 when cool enough, as the emulsion is best diluted with 

 hot water, by means of a knapsack machine, spraying 

 very lightly on the plants, or, in case of small areas, 

 try a fine-rose watering can. The spraying will re- 

 quire to be done twice or more often during the 

 season. 



Other good washes that have proved beneficial are : 

 (# ) Carbolic acid, one pint, and soft soap, half a pound, 

 to ten gallons of water, thoroughly incorporating the 

 acid with the soft soap, and then diluting with water. 

 () Gas tar water : half a pound of gas tar boiled for 

 half an hour in two gallons of water, diluting to fifty 

 gallons with water. This is, perhaps, the most repug- 

 nant of all washes to leaf-blister flies. (<:) Boil four 

 ounces of quassia chips in a gallon of soft water for a 

 quarter of an hour, and dissolve in it, as it cools, four 



