﻿32 



BUIxLETIN 1357, U. S. DEPARTMENT OF AGRICULTURE 



Table 13. — Expervmewts with arsenical dusts on caged strawberry rootworm 



beetles — Continued 



Sixth day 



Material and strength 



Dead 



Feed- 

 ing 

 punc- 

 tures 



Seventh day j Total 



Dead 



Feed- ' 



punc- 1 ^^"^ 

 tures j 



Feed- 

 ing 

 punc- 

 tures 



Control 



Remarks 



Sulphur 90 parts.. 



Arsenate of lead 10 parts.. 



Sulphur - 90 parts.. 



Arsenate of lead 10 parts.. 



Sulphur.. 90 parts.. 



Arsenate of lead 10 parts.. 



Sulphur - 80 parts.. 



Arsenate of lead 20 parts.. 



Sulphur 80 parts.. 



Arsenate of lead 20 parts.. 



Sulphur 80 parts.. 



Arsenate of lead 20 parts.. 



Sulphur ...80 parts.. 



Arsenate of lead 10 parts.. 



Bordeaux, dry 10 parts. . 



Sulphur SO parts.. 



Arsenate of lead 10 parts.. 



Kaolin ...40 parts.. 



Sulphur 80 parts. . 



Arsenate of lead 15 parts.. 



Powdered sugar 5 parts.. 



Arsenate of lead, pure 



Sulphur 90 parts.. 



Calcium arsenate 10 parts.. 



Sulphur -.90 parts.. 



Calcium arsenate 10 parts.. 



Sulphur 80 parts.. 



Calcium arsenate 20 parts.. 



Sulphur 80 parts.. 



Calcium arsenate 20 parts.. 



Calcium arsenat.e---2 pounds.. 



Water 50 gallons.. 



Sulphur 50 parts.. 



Calcium arsenate 10 parts.. 



Kaolin 40 parts.. 



Sulphur 72 parts.. 



Arsenate of lead 18 parts.. 



Cornstarch 10 parts.. 



Sulphur 81 parts.. 



Arsenate of lead 9 parts.. 



Cornstarch. .10 parts.. 



Hellebore, dry 



6 



Sulphur, pure 



Check (untreated leaf) . 

 Do. 



Do. 



Check (no food, 14 beetles).. 



(1) 



0) 



36 

 (1) 



(') 



(') 



Per cent 

 iOO 



60 

 100 

 100 

 100 



60 



43 

 129 



100 



100 

 100 



100 



100 



100 



100 



1 alive. 



1 dead on eighth day, 

 1 dead on ninth day. 



2 escaped. 



1 died on eleventh day. 



Solution sprayed. 



3 died on eleventh day. 



1 died on eleventh day. 



Fresh untreated leaf 

 given on sixth day. 



New leaf given on fifth 

 day. 



All dead on fifteenth 

 day. 



1 No data. 



In the third establishment dusting was practiced to only a limited 

 extent during 1920. In 1921 a heavy infestation existed and dusting 

 was employed as one of several methods of controlling the beetles. 

 After the plants had started new growth following the cut-back 

 period (fig. 14), they were kept continually dusted until the middle 

 of November, at which time very few beetles were to be found, and 

 it was supposed that they were in their usual inactive state for the 

 winter. For the first month the sulphur-arsenate of lead (10 per 

 cent) mixture previously mentioned was applied, and after that the 

 following dust mixture was used : 



Pounds 



Superfine sulphur (200 mesh) 80 



Calcium arsenate 15 



Powdered sugar 5 



