23 



ical Works, New York, and probably from other leading dealers 

 in similar products for 15 cents per pound. 



EXPERIMENTS WITH GREEN ARSENITE- 



No strictly comparative experiments with this insecticide have 

 been made here at the Station. Comparative tests" by C. L,- 

 Marlatt however, indicate that green arsenite and Paris green are 

 equally eflFective as insecticides. 



Experiments with green arsenite made by the writer are 

 recorded on pages 600-601 of Bulletin 136 of this Station and on 

 previous pages of this Bulletin. In the former instance the 

 insecticide was successfully used against a flea beetle, Systena 

 kudsonias Forst. attacking young apple grafts, and in the latter 

 with equal success against the cottonwood leaf-beetle, Lina 

 scripta Fab. 



In the spring of 1896 and again in 1897, the writer used green 

 arsenite against the spring canker worm in an orchard near the 

 Station. Fourteen large bearing apple trees were used in the 

 experiments. Both seasons the trees were sprayed three times, 

 the first being about the middle of May and the remaining two 

 from a week to ten days apart. In 1896 the remainder of the 

 infested orchard was sprayed with ordinary Paris green, and in 

 1897 ^'^ green arsenite alone was used. In 1896 the trees 

 sprayed with green arsenite were more uniformily free from 

 canker worms than those sprayed with Paris green, while 

 in 1897 the sprayed trees were practically free from canker worms 

 after the second application, which was made May 22, while the 

 unsprayed trees were nearly stripped of their foliage. 



In addition to the above experiments the writer has used green 

 arsenite upon young pear trees against the fruit worm and upon 

 potatoes against the Colorado potato beetle. In both instances 

 the poison was used at the rate of i pound to 150 gallons 

 of water with the addition of enough freshly slaked lime to 

 make the mixture slightly milky in appearance, and gave every 

 indication of being equally as efficient as Paris green. 



»U. S. Dept. Ag. Div. of Ent., Bui. 6, new ser.: 30-35. 



