12-2 HOP. 



held as to migration ; but still I do not myself think that in 

 this country the whole of the attack comes on the wing from 

 Plum, Damson, or Sloe. 



I think this because we have found Aphides (that is, wing- 

 less females and lice), on Hop as early as the end of March 

 and the beginning of April, long before the attack coming on 

 the wing made its appearance. 



Just to give a few instances : — In 1884 Mr. C. Whitehead, 

 writing to me from Barming, Maidstone, on the 29th of 

 March, mentioned, " I have found the enclosed Hop- shoot, 

 with the larvffi in situ, in my Hop-ground this morning. 

 There was a wingless female, which had evidently deposited 

 viviparously the larvse enclosed." ..." I dress late, and so 

 I have plenty of shoots which will soon be cut off, and upon 

 these I found the lice I sent to you. I went out in the after- 

 noon and found lice upon many of the hills," ..." where 

 there were small lice, in most cases a wingless viviparous 

 active female was not far off. I found them chiefly in a part 

 sheltered from cold winds, and where hatching or awakening 

 from hybernation would be early. I should say I found a 

 hundred at least in ten minutes." 



On the 31st of March (that is two days later) I had infor- 

 mation from another locality in Kent, of some "lice" being 

 found on " Grape " Hops. Early in April, Mr. Whitehead 

 further wrote me that he had found more "lice" on Hop- 

 shoots, and that two farmers had just called and brought more, 

 and on the 12th of April Dr. T. A. Chapman, writing from 

 Hereford, reported that after careful search in the Hop-yards 

 where the bine was two feet high, he could find no trace of 

 ''Fly," but on the following day he found a bine with seven 

 or eight Aphides on it. These were wingless and nearly full- 

 sized. 



Also in the Stoke Edith experiments, made in 1884,* it was 

 found that in the case of the Hop-hills which were dressed 

 with applications to keep the Aphides from coming up from 

 around the Hop-plant, the bines on these hills (more than 

 twelve hundred in number) were free from attack until the fly 

 came at the end of May, although the rest of the Hop-yai'd teas 

 infested. 



We do not know the reason of this at present, but it may 

 at least be conjectured that it is owing to hybernation of the 

 Aphis pest in the Hoi^-hill. 



Peevention and PiEMEDiES. — Thcso various observations 

 point to some benefit being obtained by dressing hills so as to 



* For detailed observations on Hop Aphis see Appendix to my Eeport on 

 Injurious Insects for 1883, and Keport for 1884. 



