The Hop Aphis. 



77 



for this insect, but it may serve the purpose for others, so that 

 it is well to destroy it. Large branches, however, should be 

 treated as recommended for stems. The Pine Beetle will also 

 breed in the part of the stools above ground, and in the month 

 of May the bark of stools should be pressed off by means of a 

 spade, or other suitable tool, and, being generally thick, should 

 be burned. 



All pines that die in the course of the summer should be 

 felled and barked within two months. 



By attending to these simple directions most of the damage 

 from which an important section of our forest trees suffers 

 through the attack of this insect will be avoided.* 



The Hop Aphis.* 



The chief insect pest with which the hop grower has to contend 

 is the Hop Aphis {Phorodon humuli), also known as the Hop 

 " Fly " or " Louse." In former years, before the introduction of 

 washing to combat this pest, the hop crop was often almost 

 entirely destroyed by its attacks ; hops would rise to famine 

 prices, since so few could be picked from the gardens which 

 partially recovered from the invasion or had escaped it wholly. 

 The last general "black blight" occurred in 1882, since which 

 year washing has been universal among the good growers of 

 hops, but even the past three years have seen attacks which have 

 seriously affected the crop either in quality or in yield. Early 

 in June the first symptoms of an attack are usually to be seen ; 

 here and there among the hops will be found a stout-winged 

 green aphis, and on the underside of the unfolding leaves, near 

 the tips of the shoots, minute wingless " lice " may be detected, 

 the soft growing points of the plant being always the part first 

 attacked. If the weather conditions are favourable and nothing 

 is done, the aphis multiplies with inconceivable rapidity ; in a 

 week or two the undersides of all the leaves become dotted over 

 with wingless lice of all sizes, while the sticky exudations from 



* Copies of this article, in leaflet form, may be obtained free of charge and post 

 free, on application to the Secretary, Board of Agriculture, 4, Whitehall Place, 

 London, S.W. 



