Cultivation of Arable Land. Heps Difeqfes of-*-Fen Mildew. 25 1 



probable, and more confonant to analogy j fince from its tafte, which refcmbles that 

 t&amp;gt;f the vernal fap-juice of plants, and its fupporting bees, ants&amp;gt; and other infects, it 

 muft be of a nutritious quality.* This fuppofition is rendered (till more probable 

 from the circumftance of its occurring after the infects have been fome timeprefent 

 upon the plants, and difappearing long before they leave them.t It would appear 

 indeed that this exudation may in fome meafure be caufed by the punctures of the 

 infects, as it moft commonly takes place after the nights have been cold, moift, 

 and foggy, and the fucceeding days hot and funny, the irritability of the plants 

 being fo much incrcafed by the former as to render the action of the latter more 

 powerful in promoting the circulation of their juices, and confequently in forcing 

 their pafTage more abundantly through the fine openings afforded by the punctures 

 of fuch infects. 



This difeafe moftly happens in the more forward drops. The chief dependence 

 of the planter for its removal is that of heavy thunder mowers taking place, as by 

 this means, when the deftruction of the hops has not proceeded too far, they are 

 often much reftored, the infects that devour the leaves and binds being greatly de- 

 ftroyed.the growth of frefli (hoots promoted, and a favourable bloom brought on.j 



Thefen mould, or mildew, is a difeafe to which the hop is expofed at a later period 

 of its growth. It chiefly attacks the part where the hop is attached to the ftem. 

 Its production is greatly promoted by moift damp weather and a low fuuation ; 

 thofe hop-crops that grow on low, clofe, rich grounds being the mod liable to be 

 attacked by it* It is found to foon fpread itfelf over the whole crop, after it has 

 once feized upon any part of it. The nature of this vegetable difeafe is not pro 

 bably yet perfectly underftood. It has lately however been ingcnioufly fuggefted 

 to be a plant of the fungus kind, that is capable of growing without light or 

 change of air, attaching itfelf to the plants already in a morbid condition, and by 

 its roots penetrating their vefTels. On this fuppofition, the bed remedy is believed 

 to be that of thinning the plants or wholly removing thofe immediately about it, 

 in order to afford a more free circulation of air, and admit the light more extenfively ; 

 by which the vigour of the hop-plants may be reftored, and the difeafe be of courfe 

 removed. If this opinion ef the nature of the difeafe be well founded, it is proba 

 ble that by planting the hills more thinly, and making them at greater diftances 

 from each other, this vegetable malady might be in a great meafure prevented from 

 occurring in thofe fituations where it moft frequently fhows itfelf. 



Blights are frequent in hop crops; but the caufes of them do not appear to 



.* Danvin i Phj-fologia. t Ibid. \ Synopfis of Husbandry. Danrin ; Phytologia. 



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