20 FUMIGATION METHODS 



Hand was not hurt. At 0.75 gramme Ogon had ter- 

 minals slightly injured^ as shown in Fig. 2, while 

 Spalding was killed to the ground, but later sent out 

 shoots at the base. At i.oo gramme Ogon was again 

 only slightly hurt, while Abundance was dead to the 

 surface of the ground. From i.oo to 1.35 Ogon was 

 slightly injured on the terminals, as can be seen in 

 Fig. 3- 



The general conclusions drawn from these tests 

 with plum are (i) that no injury will result where 

 normal dose is used for one hour or less on well- 

 matured trees over two feet in hight, and (2) that 

 some varieties are more resistent to injury from over- 

 doses of gas than others. 



Peach trees. The experiments upon peach trees 

 were commenced April 26, 1899, after the buds had 

 begun to swell. There were 250 trees, one-half of 

 which were first-grade Peninsula Yellow, 4 to 5 feet, 

 while the others were very small, varying from i^ 

 to 2 feet high. The trees were divided into lots of five 

 each, and both grades treated from 0.25 to 1.45 

 grammes cyanide per cubic foot, 0.05 gramme being 

 added each time. In every instance the short grade 

 trees, known as ' ' whips, ' ' were killed outright, or the 

 tops were killed, sending out few feeble shoots near the 

 ground later. This corresponded to results obtained in 

 1898, that June-budded peach and plum, and small whip- 

 like trees from i^ to 2^ feet, can not withstand more 

 than o. 1 8 gramme for half an hour. On the other 

 hand, with large trees there was no perceptible injury 

 from 0.25 gramme up to 0.50 gramme. At the latter 

 strength, double the normal, the terminals were injured 



