s 



354 



DISEASES 



Sect. XIV. 3. 2. 



\ 



branches of a nedarine-tree, which was covered with the aphis ; but 

 it killed both the infecl and the branches. A folution of arfenic much 

 diluted did the fame, 

 fmcared.on a fruit-wall deter the flies from approaching the trees to 



Might not the fcent of turpentine, or of tar, 



depofit their 



ecro-Q 



? 



or 



might 



not arfenic mixed with honey be 



fmcared on the wall, to which the trees are nailed, be likely to at- 

 tra6l the aphis as well as other kinds of flying Infeds. But none of 

 thefe fliould be fmearcd on the branches, left it injure or defl:roy the 

 tree. Perhaps if a few twigs fmeared with turpentine, mixed with a 

 little oil of turpentine to make it more fluid, and. to inqreafe its odour, 

 were fixed in quince- trees,, or- in .apple-trees, the flowers of which 

 are liable to be deftroyed by the eggs depofited in them by a fmall 

 fly; they might be deterred. from approaching the tree, as the great 

 ufe of eflential oils, which caufe the fragrance of- flowers, feems t,o 

 be to deter infedls from infefting their leaves,, or preying. upon their 

 honey. 



% 



, It is probable, that if infufions were made in hot water, or perhaps 

 for a longer time in cold water, of thofe leaves which no infeds de- 

 vour ; as of the walnut, juglans j lauro-cerafus, , laurel; foxglove, 

 digitalis; hen-bane, hyofcyamus ; hounds-rtongue,. cynogloflAjm; 



rao;-wort, f( 



d 



many 



jacobasa ; or .of tobacco, nicotiana ; 

 others ; and were fprinkled on the curled leaves of w 

 the buds before they open, by a pump, or by a brufh, or fpono-e; 

 they might deftroy the infeds. without injuring the treQs,vvhic]i 



■f 



\ 



might be determined by. a few experiments. 



The duft of tobacco is frequently fpread on affedled leaves,, but not 

 Lbelieve with very encouraging fuccefs, owing perhaps to the powder 

 not being very fine,, or not foon enough applied. Some kinds of lime 

 flrewed on in powder might probably be too cauflic, and defl:roy the 

 leaf along with the infeas ; which alfo might be fubjeded to experir 

 ment. The powder of fulphur, or of tobacco, or of any of the poi- 



foiiousJeay.es above meiitioned, might be injeaed upon aiTeded trees 



— ^ 

 »' 



