1B2 DISEASES OF CROPS. 



spring, by piercing the shoots ; and, later in the season, 

 the white larvae feed on the " cones," etc., of the hop- 

 plant. The eggs are deposited in the cones, bine, or 

 under the cuticle of the leaves ; and when laid in the 

 summer they are hatched in about twelve days. The 

 beetles are of a greenish-black hue, " with a brassy tint," 

 and the elytra are dotted. According to Mr. Whitehead, 

 " these flea-beetles hibernate in the perfect state in the 

 ground close to the hop-hills, or in the hollow dead bines 

 left on the stocks, or in the pieces lying on the ground 

 near them." 



Prevention. — (1) Top-dress the young shoots with lime 

 or soot. (2) Good cultivation and a generous use of 

 manures. The application of nitrogenous and phosphatic 

 manures has been recommended. 



Cure. — (1) In the United States a solution of white 

 arsenic (arsenious oxide), in the proportion of 1 lb. to 200 

 gallons of water, is used for destroying the hop-flea 

 (Riley's Insect Life, vol. i. p. 76). (2) In the same 

 country a dilute solution of Paris green has also been 

 used for the same purpose. " American entomologists 

 wonder that we do not employ arsenic in England as an 

 insecticide. Paris green has been used in America more 

 extensively than any other substance. As a wash, about 

 a pound is put into 100 gallons of water. When used 

 dry, dusted on as a powder, about one pound is put to 

 thirty pounds of flour or gypsum, and about twenty 

 pounds distributed over an acre " (WJiitehead). 



The Hop Frog Fly (Eupteryx picta, or " jvLnnpers") 

 belongs to the same genus as the potato frog fly already 

 described. It is a small yellowish-green insect spotted 

 with black. It punctures the leaves, bines, etc., of the 

 hop-plants to extract the juices. 



