8 



these crops, estimating the number of pounds of hops at 900 per acre, and of 

 wheat at 15 bushels, equal to 900 pounds. 



The chief difference is in silica, lime, and sulphuric acid. Hence it follows 

 that gypsum, or plaster of Paris, would be a beneficial manure for hop grounds, 

 because it is sulphate of lime. It is composed of lime 32.56, sulphuric acid 

 46.51, water 20.93. Its best mode of application would be on clover after it has 

 commenced its spring growth, for in this way it would add much to the vegeta- 

 ble matter of the soil, as well as to its lime and sulphur. The crop of clover 

 should, of course, be turned under. 



In Great Britain it is usual to trench the ground with the spade ; here it is 

 an unnecessary expense. " Very deep trenching for hops," says Morton's Cy- 

 clopaedia of Agriculture, a Scotch work, " even when the top soil is not buried 

 deeply, is by no means advisable, provided there be no pan-table or incrustation 

 below." Eighteen inches is usually a sufficient depth. It may be stated as one 

 reason for not burying the surface mould very deeply, that, although the main 

 roots of the hop penetrate to a great depth, yet that the smaller rootlets, with 

 their spongioles, run only just below the surface, and the manuring ingredients 

 are continually washing downwards. We have also pretty good grounds for 

 believing that rich soil buried deeply becomes inert." 



If the soil requires manuring and deepening, this should first be done by 

 the gypsum-dressed clover turned under to the depth of ten inches. When 

 broken up to plant the hop roots, it should be subsoiled an additional depth of 

 eight inches. Trenching with the spade is a useless waste of labor where the 

 plough can be used, and hops should not be planted where it cannot ; for, as 

 the hop demands a loose, deep soil, it would soon be washed away on hill-sides. 

 Barn-yard manure should always be applied during the cultivation of the 

 crop, and even before, if the soil is not rich. In Great Britain alluvial soils are 

 regarded as excellent ; and clay soils, especially if tenacious, should be thor- 

 oughly drained, for a plant so deeply rooted as the hop should not have its 

 lower roots imbedded in standing water. 



The situation of the hop-field should be free from heavy winds, as they blow 

 down the poles, but it should be well aired and sunny. The reason of this will 

 be seen when speaking of the disease of mould. 



3d. Enemies and Diseases. — We have seen how uncertain the hop crop is. 

 This is chiefly owing to its enemies and diseases. In England these are numer- 

 ous ; but here it will not be necessary to notice but one of each — the aphis, or 

 louse, and the mould. They will be noticed at some length, however. 



1. The Aphis. — The correspondents of this department, in speaking of the 

 injuries received by the hop crop of 1864, describe these insects, so common to 

 many plants, and speak of them as lice. The following description of them is 

 given by Mr. Harris : 



" The winged plant-lice provide for a succession of their race by stocking 

 the plants with eggs in the autumn. These are hatched in the spring, and the 

 young lice immediately begin to pump up the sap from the tender leaves and 

 shoots, increase rapidly in size, and in a short time come to maturity. In this 

 state it is found that the brood, without a single exception, consists wholly of 

 females, which are wingless, but are in a condition immediately to contimie their 

 kind. Their young, however, are not hatched from eggs, but are produced 

 alive, and each female may be the mother oi fifteen or twenty young lice in the 

 course of a single day. The plant-lice of this second generation are also wing- 

 less females, which grow up and have their young in due time ; and thus brood 

 after brood is produced, even to the seventh generation or more, without the 

 appearance or intermixture, throughout the whole season, of a single male. 

 This extraordinary propagation ends in the autumn with a birth of a brood of 

 males, which in due time acquire wings, and pair ; eggs are then laid by the 



