154 DISEASES OF CROPS. 



in the ground. According to Mr. Whitehead they are 

 rare. 



Prevention. — A thorough cleaning of the land is essen- 

 tial, as the larvse of Hepialus feed on the roots of the 

 common nettle, burdock, and other weeds. 



Cure. — In Germany crude naphthalene has been used 

 with marked success. A small quantity of this substance 

 is placed round the stocks of the vines. 



The Hop Snout Moth {Hypena rostralis) is about 

 an inch across the extended wings, and is known by the 

 snout-like appendage of the head. The larvae are of a 

 green colour, and feed upon the leaves of the hop-plant. 

 They pass the pupal stage on the leaves. 



Prevention and Cure. — See those recommended for the 

 " hop frog fly " and the " hop aphis." 



The Hop Wireworm {Elater lineatus) is the larva 

 of the " striped click beetle." The beetle is somewhat 

 like E. obscurus (Fig. 36 B), but is distinguished from the 

 latter species by having the elytra striped with grey- 

 coloured lines. The larvse of E. lineatus attack the new 

 shoots of the hop-plants. 



Prevention and Cure. — See under the head of " Click 

 Beetles " in chapter iv. 



The Red Mite {Tetranychus telarius)— the so-called 

 " red spider "-^differs from the true spiders by having the 

 head, thorax, and abdomen all in one piece. It belongs to 

 the same genus as another " red spider " {T. Moculatus) 

 which threatens serious mischief to the plants of the 

 newly-made tea plantations of Assam. T. telarius causes 

 considerable damage to hops, particularly in dry seasons. 

 The leaves of the hop-plants " turn brown, become 

 shrivelled, and fall off." 



Cure. — Mr. Whitehead recommends " washing the 



