29: 



ON FORMS OF THE HOP {HUiMULUS LUPULUS 

 L. AND H. AMERICANUS NUTT.) RE818TANT TO 

 MILDEW {SPHAEROTHECA HUMULI (DC.) BURR.). 



IV. 



By E. S. salmon, 

 Mycologist, S.E. Agricultural College, Wye, Kent. 



In previous articles (i) (2) (3) it has been pointed out that resistance to the 

 attacks of the mildew Sphaerotheca Humuli (DC.) Burr, is found in certain 

 forms of Humulus Lupulus L., viz., (1) in a variety known to nurserymen 

 as the "Golden Hop," and (2) in certain seedlings of the wild plant 

 obtained from Italy. Experiments have now demonstrated the existence 

 of a form of H. americanus Nutt. resistant to mildew. Our present 

 knowledge with respect to these three groups of mildew-resistant hops 

 is given below. 



(1) The "Golden Hop." 



Several distinct forms of H. Lupulus with yellow ("golden") leaves 

 are on sale by nurserymen. These forms are quite distinct, and in several 

 instances the stocks in nurseries have become mixed. The following 

 information has been collected wdth respect to the characteristics, origin 

 and name of these forms. 



(1) Plants were obtained under the name of "Golden Hop" from 

 Messrs Bunyard and from Messrs Bide and Son. In both cases the stock 

 proved to be mixed, the plant sent being sometimes female and immune, 

 and sometimes male and fully susceptible to mildew. Mr E. A. Bunyard 

 has written to me: "I fancy our ' Golden Hop' came from Messrs Bide 

 and Son, but no record was kept." Messrs Bide and Son wrote, in March, 

 1916: "We bought the plants in the first place from M. G. Benard, 

 Orleans, France. We do not claim to be the introducers of this plant, 

 as we quite think it is to be had from other firms in this country." In 

 Feb. 1918, Mr A. R. Bide wrote : " I cannot tell you definitely how many 

 years we have listed this, but it is certainly 8 to 10. I first saw this 

 growing in the nursery of Messrs Turbat et Cie, when I was at Orleans, 

 and as I had never seen the Golden variety before, I bought some. Since 



20—2 



