THE SPEUCE GALL-LOUSE 



(CHERMES ABIETIS) 



NEW APPLICATION OF FUMIGATION 

 — PERFECT SUCCESS ATTAINED 



A LETTER FROM 



G. E. FISHER 



PROVINCIAL INSPECTOR, SAN JOSE SCALE 



G 



ALL-LICE are so protected in the galls they 

 produce as to be practically beyond the 

 reach of sprays. Whale oil soap, crude 

 petroleum, kerosene, fish oil, and a strong solution 

 of caustic potash were used without result. Fumi- 

 gation with the gas from the cyanide of potash is the 

 only effective remedy I am acquainted with, and this 

 has proved very satisfactory indeed. In treating 

 insects the life history must be carefully observed, 

 some points of which are said to be as follows : — 



The gall louse lays its eggs in the fall, one egg in each section of the bud 

 attacked. The eggs are hatched by the warmth of the following spring. 

 During the balance of its season the insect is viviparous. As many as 



t we n ty-fi ve 



Fig. 2391. 



Fig. 2393. 



Fig. 2392. Spruce Galls. 



lice have been 

 f o u nd in a 

 single cell — 

 which mature 

 and leave the 



cell during August and some 

 possibly in July. Treatment in 

 winter is not practicable because 

 of the difficulty of destroying the 

 vitality of eggs, and, as the 

 mature insects are moving in 

 August, treatment in July is likely 

 to be most effective and should 



be done at night and when the foliage is dry, to 



avoid injuring it. 



One-seventh to one-sixth of a grain of cyanide 



to the cubic foot, enclosed with an exposure of 



forty minutes, will kill the lice without affecting 



the spruce tree injuriously. 



We have some cases of injury where the foliage 



was wet, a gas of greater strength used, or the 



work done during the heat of the day. 



