MISCELLANEOUS CBOPS. 149 



of cucumbers in the second week in August (1887), and 

 have used the iron sulphate. I find no trace of disease, 

 although the plants were diseased when I first wrote to 

 you in August. I have been able to cut scores of fruits of 

 the most splendid quality, and they have been extraordi- 

 narily fruitful. It is the first house of cucumbers I have 

 grown without disease for at least ten years." i 



(5) The Parasites op Hops {Rumulus lupulus). 



According to Linnseus {Linncei Amaenitat. Academ. vii. 

 p. 452) hops were brought to Europe by the Goths from 

 Asiatic Eussia. Whether this be true or not, their proper 

 cultivation in this country only dates from 1524.^ Hops 

 require a rich, deep soil, and should be grown on freshly 

 broken, well drained, and highly manured land. 



The Hop Aphis (Phorodon humuU), " green fly," or 

 " hop blight," is too well known among hop-growers to 

 require anything more than a general description. " The 

 genus Phorodon, to which it belongs, is distinguished from 

 others of the Apliidince by the horns (antennse) being 

 hardly longer than the body, together with the lowest 

 joint being toothed or gibbous, and the tubercles on the 

 forehead each having a strong tooth." Dr. C. V. Riley ^ 

 was the first entomologist who conclusively proved that 

 P. humuli hibernates upon damson, plum, sloe, and other 

 trees of the genus Prunus. He says in Insect Life, vol. i. 

 p. 134: "Hibernating at the present season of the year 



' A Treatise on Manures, p. 302. 



^ Houghton's Husbandry and Trade Improved, vol. ii. p. 457 [a.d. 

 1727] . 



3 Gardeners' Chronicle, Oct. 27th, 1887 ; Insect Life, vol. i. pp. 70 

 and 133. 



