THE PEAR. 



465 



to our estimation of their respective qualities, 

 we cannot do better than quote what Mr R. 

 Thomson says on the subject in the third edi- 

 tion of the " Catalogue of Fruits in the London 

 Horticultural Society's Gardens." " It is neces- 

 sary to observe, that varieties esteemed of the 

 highest excellence by some are deemed inferior 

 by others. In general, this diversity of opinion 

 is owing to difference of soil, situation, or climate; 

 for if these are unfavourable, a variety which 

 proves to be first-rate, when produced under fa- 

 vourable circumstances, is often found inferior to 

 one that, although second-rate, is more hardy." 



The number of varieties now in cultivation is 

 very great. The Romans, in Pliny's time, pos- 

 sessed 36 varieties. Parkinson enumerates 64 ; 

 Miller, 80. The " Luxembourg Nursery Cata- 

 logue " at Paris contained 1 89 select sorts about 

 the beginning of the present century. The " Cata- 

 logue of the Horticultural Society" contains 

 442 described sorts. G. Lindley, in " Guide to 

 the Orchard," 162; Rogers, in " Fruit Cultiva- 

 tor," 50 ; Downing, an American author, 233, 

 many of which are of American origin ; P. 

 Lawson and Sons' " Fruit Catalogue," 267 ; Mr 

 Rivers, in " Descriptive Catalogue of Pears " 

 for 1843-4, enumerates 156 sorts of dessert pears 

 and 14 baking and stewing sorts, of all which, 

 Mr Rivers informs us, he has specimens in a 

 bearing state, and from which his grafts are 

 taken, which insures correctness of nomen- 

 clature. 



DISEASES. 



The pear is much less liable to disease than 

 the apple, at least in Britain. In America, and 

 also in France, it is otherwise. In the former 

 country, two diseases often assume a decided 

 character, the one called The Insect Blight, and 

 the other The Frozen Sap Blight, appearing 

 sometimes in succeeding seasons, and again 

 only after the lapse of several years. The in- 

 sect "blight is thus described by Mr Downing, 

 in his excellent work, " The Fruits and Fruit 

 Trees of America:" — u In the month of June 

 or July, when the tree is in full luxuriance or 

 growth, shoots at the extremities of the branches, 

 and often extending down two seasons' growth, 

 are observed suddenly to turn brown. In two 

 or three days the leaves become quite black and 

 dry, and the wood so shrivelled and hard as to 

 be cut with difficulty with a knife. If the 

 branch is allowed to remain, the disease some- 

 times extends a short distance farther down the 

 stem, but usually not much farther than the 

 point where the insect had made his lodgment." 

 This insect has been described by Professor 

 Peck under the name of Scolytus pyri. " It is 

 very minute, being scarcely one-tenth of an inch 

 long; and it escapes from the branch almost as 

 soon as, by the withering of the leaves, we are 

 aware of its attack : hence it is so rarely seen 

 by careless observers. In the perfect state it is 

 a very small beetle, deep brown, with legs of a 

 paler colour. Its thorax is short, convex, rough 

 in front, and studded with erect bristles. The 

 wing- covers are marked with rows of punctured 

 points, between which are two rows of bristles, 

 and they appear cut off very obliquely behind. 



This insect deposits its eggs some time in July or 

 August, either behind or below a bud. Whether 

 the egg hatches at once we are not aware, but the 

 following spring the small grub or larva gnaws 

 through the sap-wood, or tender alburnum, 

 beginning at the root of the bud, and burrows 

 towards the centre of the stem. Around this 

 centre or pith it forms a circular passage, some- 

 times devouring it altogether. By thus perforat- 

 ing, sawing off, or girdling internally, a consider- 

 able portion of the vessels which convey the 

 ascending sap, at the very period when the rapid 

 growth of the leaves calls for the largest supply 

 of fluid from the roots, the growth and the vita- 

 lity of the branch is checked and finally extin- 

 guished. The larva, about this time, completes 

 both its transformation and its passage out, and, 

 in the beetle form, emerges with wings into the 

 air, to seek out new positions for laying its eggs 

 and continuing its species." The remedy pur- 

 sued for the destruction of this insect con- 

 sists in cutting off the branches about a foot 

 below the point where it has fixed its abode, 

 which is readily discovered by the discoloration 

 in the bark, and this operation should be carried 

 into effect upon the very first indication of its 

 appearance. 



The frozen sap blight is occasioned by the 

 trees continuing to grow late in autumn, and 

 being attacked by early autumnal frosts while 

 the sap-vessels are full of fluid matter. By alter- 

 nate freezing and thawing of the sap it loses its 

 vitality, and becomes dark and discoloured ; and 

 in some cases, Downing remarks, it becomes so 

 poisonous as to destroy the leaves of other plants 

 when applied to them. So serious is this dis- 

 ease in some parts of America, as to create great 

 alarm amongst the cultivators of fruits. " To 

 distinguish the blight of the frozen sap from 

 that caused by the attacks of the Scolytus pyri," 

 Mr Downing remarks, " is not difficult. The 

 effects of the latter cease below the spot where 

 the insect has perforated and eaten its burrow in 

 the branch, the former spreads gradually down 

 the branch, which, when dissected, shows the 

 marks of the poison in the discoloration of the 

 inner bark and the pith, extending down some 

 distance below the external marks of injury. If 

 the poison becomes largely diffused in the tree, 

 it will sometimes die outright in a day or two ; 

 but if it is only slightly present, it will often 

 entirely recover. The presence of black, dry, 

 shrivelled spots of bark on the branches, or soft 

 sappy spots, as well as the appearance of thick 

 clammy sap in winter or spring pruning, are the 

 infallible signs of the frozen-sap blight." We are 

 not aware that such a disease has yet made its 

 appearance in Europe, although others may exist 

 of less virulence, arising from similar causes in 

 certain seasons. Duhamel, in " Traite des Ar- 

 bres Fruitiers," mentions a diseased state in the 

 sap, arising from excess of manure, somewhat 

 analogous to this American disease. He says, 

 " The sap, corrupted by putrid water or the ex- 

 cess of manure, bursts the cellular membranes 

 in some places, extends itself between the wood 

 and the bark, which it separates, and carries its 

 poisonous acrid influence to all the neighbouring 

 parts like a gangrene." " In a soil over-moist 



