N 



EXPEEIMENTS WITH SPRA-Y SpI^UTJO^g fc F9R;GJlEHN LOGS. 11 



Consequently, to determine just how effective these solutions were 

 against ambrosia beetles (Table II), "the water-soaked logs were 

 thoroughly sprayed with (1) 4 parts kerosene plus 1 part creosote 

 oil, (2) the corrosive sublimate solution as given before, and (3) 1 

 part crude pyridin preparation to 8 parts kerosene. All the sticks 

 were dried for 24 hours before the sprays were applied. These 

 materials were applied to three pines, one oak, and one ash log, July 

 28, 1920. The results are given in Table II. 



TABLE II. Results of c-rpcrinictit^ in the treatment of water-soaked logs 



(unhrosia beetles. 1 



1 Numbers refer to ambrosia beetles attacking except when followed by letter. 

 Not counted. 



a=species of Ips, type 4. x=many ambrosia beetles not counted. 



POISONING OF AMBROSIA BEETLES. 



To determine whether ambrosia beetles feed on the bark as they 

 bore through it, and consequently whether poison spray could be 

 effective against them, several water-soaked ash logs were dried for 

 48 hours to remove the excess water from the bark and then com- 

 pletely submerged for 48 hours in a solution of sodium arsenate, 2 

 pounds to 10 gallons of water. 



A wooden frame with a cheesecloth bottom was prepared on the 

 ground, and on supports above this frame a rubber cloth was sus- 

 pended to keep any rain from reaching the treated sticks. The sticks 

 were placed in the box on the cheesecloth and the cloth was carefully 

 examined every two or three days for dead ambrosia beetles. The 

 treatments were made on May 30, 1920. An untreated control was 

 used in the same position. The results were as follows: 



June 8, one dead beetle beneath sticks. 



June 15, one beetle boring through bark. 



June 23, two beetles boring through bark. 



July 23, two to six beetles were in each stick and all galleries contained 

 eggs and various stages of larvae. 



These beetles were evidently not deterred or injured by the poison. 

 At no time were the sticks wet. It is quite probable that the dead 

 beetle found June 8 was not killed by the poison, since no other dead 

 insects were found. 



