8 BULLETIN" 992, 17. s. DEPARTMENT OF AGRICULTURE. 



ripe. The Bush grove, however, was kept under close observation 

 by Mr. Rush and the writer. The flies became very numerous on the 

 trees of this grove for a period of a few days after the spray was 

 applied and then decreased in numbers. 



Examination and counts of the nuts of the sprayed trees in the 

 Baile grove just before the crop was gathered showed that 4 per 

 cent of the nuts had been attacked by the maggots, whereas at least 

 60 per cent of the crop had been destroyed by the maggots the pre- 

 vious year. In the Rush grove it was estimated that the condition 

 was 75 per cent better than the year before when no treatment was 

 given. No Persian walnut trees were found near either the Baile or 

 Rush groves that were suitable for use in checking up definite results 

 of the spraying. However, a comparison of the sprayed nuts with 

 those produced by the same trees the previous season and with those 

 produced in other localities the same season, together with the known 

 abundance of the flies that appeared early upon the sprayed trees, 

 indicates decidedly beneficial results from the treatment. 



Flies confined in roomy wire-screen cages were observed to feed 

 freely on sweetened water to which sufficient lead arsenate had been 

 added to give the liquid a milky color. It must be admitted that 

 these flies succumbed very slowly to the poison. Further tests of 

 this treatment must be made before it can be recommended unre- 

 servedly as an effective and sure method of control for this pest. 



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