124 THE POTATO 



mixture ; hence, the only known means of reducing 

 their ravages is to spray the plants with this material. 



NUMBER OF FLEA-BEETLE PUNCTURES IN 50 LEAFLETS FROM 

 12 ADJACENT ROWS l 



Punctures 



Row i. Sprayed with very weak Bordeaux mixture . 1,794 

 Row 2. Sprayed with very weak Bordeaux mixture and 



soap 1,071 



Row 3. Not Sprayed 2,511 



Row 4. Sprayed with strong Bordeaux mixture . . 1,194 

 Row 5. Sprayed with strong Bordeaux mixture and 



soap 1,090 



Row 6. Sprayed with weak Bordeaux mixture . . . 1,295 



Row 7. Sprayed with weak Bordeaux mixture and soap 901 



Row 8. Not sprayed 2,287 



The grubs of the flea-beetle infest the tubers and 

 roots of potatoes, doing some damage and causing the 

 trouble known as "pimply potatoes." 3 



In the Pacific Coast the flea-beetles (Epitrix subcri- 

 nita, Lee., and E. hirtipennis, Mels.) sometimes reduce 

 the yield 50 per cent, by their ravages. As they are 

 leaf-eaters, the foliage should be sprayed or dusted with 

 an arsenical poison. One pound of Paris green to 150 

 gallons of water per acre is suggested, 8 but it is better 

 to apply the Paris green in Bordeaux mixture. 



THE POTATO BEETLE, COLORADO POTATO BEETLE, 

 OR POTATO BUG {Doryphora decemlineata) . Until 1850 

 this inse<5l was confined to Mexico and the Rockies. 

 In 1859 its eastward movement was noted, and it is 

 now well distributed. A related species {D.juncta} 



1 Vt. Bui. 72, pp. 6-9. 2 (N. Y.) Geneva Bui. 113, pp. 312-317. 



3 Cal. Bui. 135, p. 29. 



