21 



In the first test canvas was spread under the trees to catch the dead 

 weevils. These were collected and counted daily with results shown by 

 the following table. 



Materials 



Average number of dead weevils 

 per square foot 



24 

 hours 



Powdered arsenate of lead 2 lbs 



Lime 1% lbs 



Water 50 gal 



Same formula as above 



Powdered arsenate of lead 1 lb. 



Water 50 gal 



1.7 



1.2 



2.4 



26 

 hours 



48 

 hours 



72 

 hours 



1.3 



.6 



.6 



Total 



3.6 



2.6 



The estimated number of weevils per tree killed in 72 hours was 

 1628; and five days after the spraying it was estimated that about 50 

 per cent, of the weevils had been killed on the sprayed trees. No differ- 

 ence was seen between trees sprayed with arsenate of lead at 2 lbs. and at 

 1 lb. to 50 gallons of water. 



In the second test, sprays described in the following table were ap- 

 plied May 2, when the foliage was well developed, and again May 14. 

 For a comparison of results a conical cheese-cloth net, SJ/ feet deep and 

 3 feet across the mouth (see Figure 14), was suspended, following the 

 second application, under a representative tree in each plot, and daily 

 records were kept of the dead beetles. The tip of the net was anchored 

 to a peg driven in the ground by a cord long enough to permit the branch 

 to sway and at the same time to prevent the bag from whipping and 

 fraying in the wind. The accompanying table shows the formulae used 

 and the daily catch. 



This experiment was defective in the fact that the small num- 

 ber of trees used and their close proximity permitted the passage of 

 beetles from one tree to another after the sprays were applied, as is 

 shown especially by the appearance of dead beetles under two of the 

 check trees. It is plain, however, that the poison sprays took consider- 

 able effect, and the sprayed trees were obviously less injured by the 

 weevils than tiie check. 



Early summer application of the arsenical. — In one instance a spray 

 of arsenate of lead 1 lb., lime 2 lbs., and water 50 gallons was applied 

 to the young leaves with a spray gun at a pressure of 200 to 225 lbs. 

 when the weevils were just emerging from hibernation and before many 

 eggs had been laid. After 24 hours, 48 dead weevils were collected from 

 1U2 scfuare feet of canvas spread under the tree, and after 2(> hours more, 

 22 additional weevils were collected. 



