BLI 



BLI 



cd and shrivelled up, the rest remaining 

 green and flourishing. Some have sup- 

 posed that blights are produced by east, 

 erly winds, which bring vast quantities of 

 insects' eggs along with them from dis- 

 tant places. These, being lodged upon 

 the surface of the leaves and flowers of 

 fruil -trees, cause them to shrivel up and 

 perish. Mr. Knight, however, observes, 

 thai blights are produced by a variety of 

 causes, by insects, by an excess of heat or 

 cold, of drought or moisture ; for these 

 necessarily derange and destroy the deli- 

 cate organization of the blossoms. 



The term blight is very frequently 

 used by the gardener and farmer without 

 any definite idea being annexed to it. If 

 the leaves of their trees be eaten by the 

 caterpillar, or contracted by the aphis; 

 if the blossoms fall from the ravages of 

 insects, or without any apparent cause , 

 the trees are equally blighted ; and if an 

 east wind happen to have blown, the in- 

 sects, or at least their eggs, whatever be 

 their size, are supposed to have been 

 brought by it. The true cause of blight 

 seems to be, continued dry easterly winds 

 for several days together, without the in- 

 tervention of showers or any morning 

 dew, by which the perspiration in the 

 tender blossoms is stopped : and if it so 

 happen that there is a long continuance 

 of the same weather, it equally affects the 

 tender leaves, whereby their colour is 

 changed, and they wither and decay. 



The best remedy, perhaps, is gently to 

 wash and sprinkle over the tree, &c.from 

 lime to time, with common water ; and if 

 the young shoots seem to be much infect- 

 ed, let them be washed with a woollen 

 cloth, so as to clear them, if possible, 

 from this glutinous matter, that their re- 

 spiration and perspiration may not he ob- 

 structed. This operation ought to be 

 performed early in the day, that the 

 moisture may be exhaled before the cold 

 of the night comes on ; nor should it be 

 done when the sun shines very hot. 



Another cause of blights in the spring 

 is said to be sharp hoary frosts, which 

 are often succeeded by hot sun-shine in 

 the day-time. This is the most sudden 

 and certain destroyer of fruit that is 

 known. The chief remedy to be de- 

 pended upon in this case is, that of pro- 

 tecting the fruit trees during the night- 

 time with nets. This mode, where regu- 

 larly and correctly performed, has been 

 found highly beneficial. 



What is termed the blight is frequent- 

 ly, however, no more than a debility or 

 distemper in trees. Mr. Forsyth observes, 

 that " this is the case when trees against 



the same wall, and enjoying the same ad- 

 vantages in every respect, differ greatly 

 in their health and vigour, the weak ones 

 appearing to be continually blighted, 

 while the others remain in a flourishing 

 condition. This very great difference, 

 in such circumstances, can be attributed 

 only to the different constitutions of the 

 trees, proceeding from want of proper 

 nourishment, or from some bad qualities 

 in the soil ; some distemper in the stock, 

 buds, or scions ; or from some misma- 

 nagement in the pruning, &c. all of which 

 are productive of distempers in trees, of 

 which they are, with difficulty, cured. If 

 the fault be in the soil, it must,'* he says, 

 " be dug out, and fresh mould put in its 

 place ; or, the trees most, be taken up, 

 and others, better adapted to the soil, 

 planted in their room. It will be found 

 absolutely necessary always to endeavour 

 to suit the particular sorts of fruit to the 

 nature of the soil ; for it is in vain to ex- 

 pect all sorts of fruit to be good in the 

 same soil. If the weakness of the tree 

 proceed from an in-bred distemper, it 

 will be advisable to remove it at once, 

 and after renewing the earth to plant ano- 

 ther in its place." But if the weakness 

 is brought on by ill management in the 

 pruning, which is frequently the case, he 

 would advise more attention to the me- 

 thod of pruning and training. Besides 

 this, " there is another sort of blight that 

 sometimes happens pretty late in the 

 spring, as in April or May, which is very 

 destructive to fruit trees in orchards and 

 open plantations, and against which we 

 know of no effectual remedy. This is 

 what is called a fire-blast, which, in a few 

 hours, hath not only destroyed the fruit 

 and leaves, but often parts of trees ; and 

 sometimes entire trees have been killed 

 by it. As this generally happens in 

 close plantations, where the vapours from 

 the earth and the perspiration from the 

 trees are pent in, for want of a free circu- 

 lation of air to disperse them, it points 

 out to us the only way yet known of 

 guarding against this enemy to fruits ; 

 namely, to make choice of a clear healthy 

 situation for kitchen-gardens, orchards, 

 &c. And to plant the trees at such a dis- 

 tance as to give free admission to the air, 

 that it may dispel those vapours before 

 they are formed into such volumes as to 

 occasion these blasts." But blasts may 

 also be occasioned by the reflection of 

 the sun's rays from hollow clouds, which 

 sometimes act as burning mirrors, and oc- 

 casion excessive heat. See APHIS. 



BLINDNESS, a total privation of sight, 

 arising from an obstruction of the func- 



