11 



in small quantities of resin compounds, the following methods are 

 recommended. (1) To a boiling solution of 1 lb. washing soda in 1 gal. 

 water, 2 lb. powdered resin is added. Boiling is continued for 15 or 

 30 minutes or until the liquid becomes clear. The stock solution is 

 diluted 10 times before use. (2) For preparation on a large scale, 

 caustic soda is substituted for washing soda. Pure caustic soda, 

 30 parts, is dissolved in 900 parts of water, and to the heated solution 

 is added 180 parts resin. Upon cooling the resin soap separates out 

 as a yellow, pasty mass. The latter may be stored in this state, or 

 dried at a temperature of 100° C. and reduced to powder. The dried 

 soap is very soluble in water. The solution gives a wash of great 

 adhesiveness. On exposure to air, combination with carbon dioxide 

 takes place, resulting in the formation of sodium carbonate and resin. 

 The compound is an excellent one for use against Aphids and other 

 small insects which are not protected by hairs or wax. For Aphids, 

 a strength of 1 lb. of resin in from 8 to 12 gals, wash is sufficient ; for 

 scale-insects 1 lb. to 5 or 6 gals, should be used. The ant, Oecophylla 

 smaragdina, which is often associated with the attacks of green 

 scale {Coccus vindis) on coffee, may be greatly reduced in numbers by 

 spraying thoroughly during dull weather or in the morning or evening. 

 Scale-insects should be treated in the early nymphal stage. The 

 compound can be mixed with lead arsenate or Paris green and adds 

 to the adhesiveness of these materials. (3) Resin and fish-oil soap is pre- 

 pared by adding ^ pt. fish-oil to a boiling solution of -| lb. caustic soda, 

 1 gal. water and 3 lb. resin. This wash can be used against the above 

 insects as well as against wax scales and mealy bugs. 



The standard formula for the preparation of kerosene emulsion is : 

 ^ lb. soap, 1 gal. water, 2 gals, kerosene. For use in Malaya, the 

 wash should be diluted until it contains from 5 to 8 per cent, of kerosene. 

 A simple method for the preparation of small quantities of emulsion 

 consists of mixing together by hand, 1 lb. soap with as much kerosene 

 as will be absorbed by the soap, and diluting with 20 to 25 parts water 

 for each part of kerosene used. Crude oil emulsion, as obtained 

 commercially, contains 80 per cent, crude oil and 20 per cent, whale-oil 

 soap. It is diluted with from 45 to 90 volumes of water before use. 

 Two applications are necessary against Aphids, mealy bugs, and 

 thrips. Sanitary fluids, consisting of creosote oil, phenol, or cresol 

 emulsion, can be used against Aphids, soft scale-insects and mealy 

 bugs, at a strength of 1 part to 100 parts water. 



Locust destruction. — Div. Entom., Dept. Agric, Union S. Africa, 

 Pretoria, Bull. no. 75, 1915, 8 pp. [Received 15th December, 

 1915]. 



The locust law of the Union of S. Africa provides that whenever 

 locusts deposit their eggs, or hoppers appear upon any land, the 

 occupier must immediately notify the nearest Government official. 

 The occupier is also required to destroy the hoppers immediately, 

 and he is forbidden to drive them from his land on to that of a neighbour, 

 unless his growing crops are threatened ; even then they must be 

 destroyed if possible, and on no account may the growing crops of 

 the neighbour be endangered. Materials for control are supplied free 



