MISCELLANEOUS INSECTICIDE INVESTIGATIONS. 



31 



certain advantages. The principal points given in favor of the 

 powder over the paste are that it can be more conveniently mixed, 

 that the proper amount to be used for each spray tank may be 

 weighed out with a greater degree of accuracy, and that it can be 

 stored more readily without deterioration. There is also a distinct 

 saving in freight. For the advantages enumerated the fruit grower 

 is asked to pay a trifle more in price, since it costs the manufacturer 

 somewhat more to produce the powdered form. 



With this in view, experiments were conducted to test the efficiency 

 of the powdered form in comparison with the paste. Since the 

 powdered arsenical has approximately twice the strength of the paste, 

 one-fourth pound of the powder was directly compared with one-half 

 pound of the paste, one-half pound of the powder was compared with 



1 pound of the paste, and 1 pound of the powder was compared with 



2 pounds of the paste. All of these were combined with 50 gallons of 

 lime-sulphur solution, with the exception of Plat IV, where a com- 

 mercial precipitated sulphur was employed. 



Three spray applications against the codling moth were made: (1) 

 when petals dropped; (2) 3 to 4 weeks later; (3) 9 weeks after petals 

 dropped for second-brood larvse. 



The dropped fruit from certain count trees in each plat was picked 

 up weekly and examined. The fruit gathered at harvest time was 

 likewise examined and the results recorded. 



Plat I consisted of 9 trees, the fruit from 5 of which was examined ; 

 Plat II, 9 trees, 5 examined; Plat III, 4 trees, 3 examined; Plat IV, 5 

 trees, 3 examined; Plat V, 9 trees, 5 examined; Plat VI, 7 trees, 5 

 examined; Plat VII, 12 trees, 6 examined; Plats VIII, IX, and X, 

 total 8 trees, 8 examined. For the results of this experiment see 

 Table XVII. 



Table XVII. — Sound and wormy apples from sprayed andunsprayed plats. 

 [Benton Harbor, Mich., 1914. Poison test. Comparison of arsenate oflead in powdered and paste form.] 



Plat 

 No. 



Treatment. 



Tree 

 No. 



Condition of fruit. 



Wormy. 



Sound. 



Total. 



Per cent 

 sound. 



I 



Arsenate oflead (powder), J pound to 50 gallons 



1 

 2 

 3 



4 

 5 



28 



16 



155 



117 



61 



667 

 1,036 

 3,052 

 1,650 



806 



695 

 1,052 

 3,207 

 1,767 



867 



95.97 





Plat total... 



98.48 

 95.17 

 93.38 

 92.96 







877 



7,211 



7,588 



95. 03 





Arsenate oflead (paste), J pound to 50 gallons 







II 



1 

 2 

 3 

 4 

 5 



387 

 221 

 222 

 355 

 128 



6,979 

 5,282 

 5,064 

 5,098 

 3,771 



7,366 

 5,503 

 5,286 

 5,453 

 3,899 



94.75 





Plat total. 



95.98 

 95.80 

 93.49 

 96.72 







1,313 



26, 194 



27,507 



95.22 











