Hop-" Mould " and its Control. 



261 



contamination of the soil, it is a wise precaution (in i-ddition 

 to early sulphuring) to strip oii" the lowermost leaves of the 

 bine as early as it is safe to do so. The lower leaves of the 

 bine serve as rungs of a ladder by which the " mould " ascends 

 higher and higher towards the " burr." The lowermost leaves 

 can be removed first and tlien in one or two operations at a 

 later date the remaining leaves up to the " breast-wire " or 

 about five feet; by this plan the growth of the young hop-plant 

 does not receive too great a check. 



The spread of the disease later in the season is frequently 

 caused by the patches of " mould " present on the leaves oi 

 the " runners " growing out of the hills. The summer-spores 

 from these patches are carried by the wind to the young hops 

 where they give rise to " mould " or " red mould." The 

 " runners " should be cut off with the hoe, or — a better practice 

 — pulled out of the " hill." For the same reason any lateral 

 shoots from the stripped bine should be removed. 



(3) Avoidance of " Housirig-in.'' — With certain systems of 

 planting and training a great deal of bine is produced which gets 

 matted together at the top, the " heads " extending more or less 

 across the alleys — a condition known as " housed-in." In these 

 circumstances there is a lack of ventilation and sunshine, and 

 " mould " thrives. A system of training should be adopted to 

 remedy these drawbacks.* 



(4) Balanced Manuring. — Excess of nitrogenous manure 

 induces late sappy growth of the hop-plant, which is then 

 specially liable to be overrun by " mould." The necessary 

 phosphatic and potash requirements of the crop must not be 

 neglected.* 



(5) Provision of Male Hops. — The planting of male hops (1 

 male hill to every 200 female hills) throughout the garden 

 provides for the fertilisation of the " brush," and thus 

 appreciably shortens the critical period when the hop is in 

 " burr." The male hop must be of a variety which produces 

 pollen-dust at the time when the particular variety with which 

 it is planted is in " burr." The seeded portion gf a hop-cone 

 is less liable to " mould " than the seedless part — a fact first 

 pointed out by INIr. A. Howard when at Wye College.! 



(6) Extirpation of " Wild Hops " in Hedges and Waste Places. 

 — Where so-called " wild hops " (usually originating as 

 " cuts " thrown out from a hop-garden) exist in the neigh- 



* See A. Amos, Hop Cultivation (Joiirn. Board of Agric), XVI, 881 

 (1910). 



t See Journ S.E. Agric. Coll., XIV, 214 (1905). 



