222 MONTANA EXPERIMENT STATION. 



We found that every aphis could be killed without the least injury 

 to the foliage. Even though the experiments were conducted in 

 both cloudy and bright, hot weather, not a leaf was injured in the 

 whole series of tests. 



We used the cyanide in strengths varying from o.io grams per 

 cubic foot of inclosed space up to 0.30 grams and while o.io gram 

 killed practically all the lice, and, on the other hand, 0.30 did not 

 h'jure we decided upon 0.20 gram per cubic foot as being the suit- 

 able amount to use in practical work. 



The time of exposure was 20 minutes. 



Considering the fact that by a timely and persistent use of sprays 

 and washes the aphis may be brought under control, I very much 

 doubt if this treatment should be considered as a suitable remedy 

 except in the case of very large owners or in company orchards 

 where the expense of providing a complete fumigation outfit would 

 be justified. Having the equipment already at hand it would cost 

 about 4^/2 cents per tree to treat a large orchard. 



Information rgarding fumigation boxes suitable for such work as 

 this may be obtained from Professor Johnson's work on fumigation 

 published by the Orange Judd Publishing Co., New York. 



We also undertook a series of experiments with the use of the 

 lime-sulphur and salt wash as means of destroying the egg during 

 the winter. We sprayed a series of trees with this wash and 

 modifications of it in the Experiment Station orchard and at Lo 

 Lo. Subsequent examinations of the trees at Bozeman showed 

 that while none of the eggs hatched on the trees that were sprayed 

 they also failed to hatch on all the other trees in the same part of 

 the orchard that had not been sprayed. We therefore felt that the 

 experiment had taught us nothing. The Lo Lo experiment also 

 failed to be of value for the same reason. 



During the past few days a ])ulletin from the Idaho Experiment 

 Station, written by Profifessor Aldrich (Buletin No. 40) entitled 

 "Winter Spraying for Aphis Eggs" has come to my desk. The 

 bulletin gives in detail Prof. Aldrich's experience in the use of seven 

 diflferent sprays used in the winter treatment of eggs of this aphis. 

 The seven sprays are the following: 



I. Pure kerosene. 



