22 FUMIGATION METHODS 



slightly, as shown in Fig. 5, while a tree given a 

 normal dose, 0.25 gramme, is seen in Fig. 4. In 0.75 

 gramme the top was killed about one-third the way 

 down, as seen in Fig. 6. The engravings are self- 

 explanatory, and show the deadening effect with the 

 varying degrees of gas from the top downward. From 

 0.75 gramme to i.oo gramme it was variable. In 

 .some instances the whole top was killed. From i.oo 

 gramme up to the highest amount used, 1.45 grammes, 

 a curious fact was noticed. In almost every case the 

 injury was not as great above i.oo gramme as below 

 0.75 gramme. In 1.35 and even 1.45 the trees were 

 only slightly injured at the top, as seen in Fig. 7, 

 resembling the effects produced where 0.50 gramme 

 was used 



June-buds, grafts, and buds. Young peach and 

 plum trees, known as June-buds, should not be fumi- 

 gated with the stronger doses. Tests made in 1 898 show 

 that nursery stock of this kind will not withstand the 

 gas when generated with cyanide above o. 18 gramme 

 per cubic foot. Any wood not well matured is liable 

 to be injured if a greater amount of cyanide is used. 

 For stock of this character o. 16 to o. 18 gramme cya- 

 nide per cubic foot is recommended, at an exposure of 

 one-half hour and no longer. The scale, under ordinary 

 circumstances, is destroyed w r hen fumigated with 0.12 

 to o.i 4 gramme cyanide. The 0.15 to o. 18 formula 

 can be used with perfect safety on buds, grafts, and 

 scions. 



Roses and other siipplies. In fumigating roses and 

 other materials handled by florists the cyanide should 



