505 



The tree having been covered, one operator lifts the bottom of 

 the tent : the other, after having poured in the earthenware bowl the 

 quantity of water and acid (N.B. Pour the acid slowly into the 

 water to prevent spurting), crawls underneath and places that bowl 

 under the tent, close to the trunk of the tree, but not touching it. 

 Then at arm's length he breaks the paper cover of the cyanide of 

 potassium and drops the number of packets required into the bowl 

 holding his breath meanwhile and crawling back ; the tent is then 

 let down, earth heaped up on the circular canvas collar, and the tent 

 allowed to remain on the tree 45 to 60 minutes. Much of the poor 

 work sometimes done is to be attributed to insufficient time. 



N.B. The mere fact of covering a tree in full growth by means 

 of an air-tight tent, \\ hile the sun is up and the plant breathing, for 

 an hour or two, is enough to choke it and cause it to drop its 

 foliage, therefore be careful to only fumigate, if in the growing 

 months, in the cool of the evening or early in the morning. If the 

 tree is dripping wet or is covered with beads of dew injury to the 

 foliage might result. 



When the time is over, the operator and his assistant uncover 

 the tree by lifting the tent up, holding their breath while so doing, 

 when another tree can be covered and treated without pausing. 



Should a battery of half a dozen tents be in use, a considerable 

 number of trees can be fumigated at once and without waste of 

 time. 



Bury the residue left in the bowl after fumigation. 



NURSERY STOCK AND FUMIGATION. 



Every nurseryman now finds a fumigatorium as necessary a 

 part of his equipment as seeds, buds, and grafts. 



The young trees should be subjected to fumigation before being 

 distributed far and wide, as hydrocyanic gas is the only satisfactory 

 and inexpensive method known at present for the destruction of 

 such persistent pests as the San Jose scale, whilst, when properly 

 handled, it has no injurious effect on the stock. The fumigating 

 chambers may be made of any convenient size or material, the 

 essential point being that it shall be capable of being closed abso- 

 lutely air tight, and provided with a flue-pipe in the roof, which 

 can be opened or closed to allow of the escape of the gas after 

 fumigation. The flue should be provided with a box containing 

 caustic potash or soda to destroy the gas. The door of the chamber 

 is provided with a shutter or sliding panel at the lower portion. 



The trees having been placed on the floor of the fumigatorium, 

 the cyanide of potassium, water, and sulphuric acid are brought 

 together as explained above. At the end of an hour the shutters 



