THE FKUIT-TKEE LEAF-ROLLER. 



105 



EXPERIMENTS AT CANON CITY. COLO. 



The work at Canon City, Colo., was conducted in the orchards of 

 Mr. E. A. Davis and Dr. Allen Bell. In the Davis orchard 14-year- 

 old Ben Davis trees were sprayed, and in the Bell orchard the varie- 

 ties treated consisted of Ben Davis, Winesap, and Colorado Orange. 

 The trees in the Bell orchard were sprayed with miscible oil at the 

 strengths of 1 gallon to 12 gallons of water and 1 gallon to 15 gallons 

 of water and with 20 per cent kerosene emulsion, but unfortunately 

 the material was not at all thoroughly applied, and no conclusions 

 as to the efficiency of the sprays can be drawn from the results 

 obtained. Duties elsewhere required the absence of the writer from 

 Canon City when the applications were made. The trees in the 

 Davis orchard, on the other hand, were thoroughly sprayed with a 

 gasoline-power sprayer. The pressure maintained ranged from 150 

 to 175 pounds. At the time of the application the buds were just 

 bursting and beginning to show the green. The results are shown in 

 Table V. 



Table V. — Spraying experiments for destruction of egg masses of the fruit-tree leaf-roller, 



Canon City, Colo., 1912. 



Plat 



No. 



Treatment. 



Count 

 tree 

 No. 



Total 

 number 



of egg 



masses 



observed. 



Number of egg 

 masses — 



Percentage of egg 

 masses— 



Hatched. 



Un- 

 matched. 



Hatched. ha S- ed 



I 

 II 



Miscible oil at 1 gallon to 15 gal- 

 lons of water on April 16, 1912. 



1 



2 

 3 



4 

 5 

 6 



1 

 2 

 3 



1S4 



128 

 116 

 135 

 176 

 110 



5 



4 

 4 

 6 

 8 

 6 



124 

 112 

 129 

 168 

 104 































849 



33 



816 



3.88 



96.12 



155 

 185 



178 



155 

 184 



178 





 1 

 





















51S 



517 



1 • 



99.80 



0.20 



It will be noted that a comparison as to the number of egg masses 

 that failed to hatch between the trees on Plat I, sprayed with miscible 

 oil at the rate of 1 gallon to 15 gallons of water, and Plat II, which 

 was left untreated, shows a benefit of 95.92 per cent in favor of the 

 spraying. 



At Canon City, Colo., no experiments were performed with lime- 

 sulphur. The writer had, however, an opportunity to examine sev- 

 eral orchards in this section that were sprayed with this material 

 against the Howard scale (Aspidiotus howardi Ckll.). The lime- 

 sulphur was found to be entirely ineffective in destroying the eggs 

 of the leaf-roller. 



