4 BULLETIN 160, U. S. DEPARTMENT OF AGRICULTURE. 



pot experiment was made, discarding cactus and using the same 

 amount of arsenite of zinc. The following results were obtained : 



Table II. — Experiment Xo. 11. — Arsenite of zinc without cactus as an adhesive. 



Brownsville, Tex., 1913. 



Date. 



Beetles 

 present. 



Living. 



Dead. 



Feeding. 



Not feed- 

 ing. 



Mar. 17 



7 

 7 

 7 

 7 



6 

 4 

 4 

 3 

 3 



1 

 3 

 3 

 4 

 4 



6 

 4 

 2 

 3 

 1 



1 



Mar. IS 



3 



Mar. 19 





Mar. 21 



Mar. 29 



4 

 6 









It will be noticed here that at the end of the sixth day the mor- 

 tality was much under that of experiment Xo. 10. The plants in both 

 experiments were sprayed thoroughly, but the latter spray did not 

 spread as well as the former. In the next experiment cactus was 

 again used at the rate of 20 pounds to 50 gallons of water. The same 

 amount of zinc arsenite was used in this experiment, or 3 pounds to 

 50 gallons of water. Table III shows the number of deaths on 

 each date. 



Table III. — Experiment No. 12. — Cactus as an adhesive in combination with 



arsenite of zinc. Brownsville, Tex., 1913. 



Date. 



Beetles 

 preseni . 



Living. 



Dead. 



Feeding. 



Not feed- 

 ing. 



Mar. 17 



14 

 14 



14 



8 

 3 

 3 

 

 



6 

 11 

 11 

 14 



6 

 2 



1 

 

 



8 



Mar. IS 



12 



•Mar. 19 



13 



Mar. 21 



Mar. 22. 



14 



14 











The beetles were placed on the poisoned sugar beet at 6 p. m., 

 March 15, and in 36 hours nearly all of them were dead. 



EXPERIMENT WITH PARIS GREEN AND LIME. 



In the next pot experiment Paris green was used in place of zinc 

 arsenite and at the rate of one-half pound to 50 gallons of water plus 

 2 pounds of lime. The plant was sprayed on March 17, and as soon 

 as the poison was dry on the sugar beet the beetles were liberated 

 inside the cage. 



Table IV sums up the results. 



Table IV. 



-Experiment Xo. 13. — Cactus as an adhesive with Paris green and 

 lime, Brownsville, Tex., 1913. 



Date Beetles 

 - uate - 1 present. 



Living. 



Dead. 



Feeding. 



Not feed- 

 ing. 



Mar. 18 . 



10 

 10 

 10 

 10 



10 

 2 

 

 





 8 

 10 

 10 



6 



6 

 



4 



Mar. 19 



8 



Mar. 21 



10 



Mar. 22 



10 







