214 Means of destroying Insects and Caterpillars. 



colds and winds which have prevented il from setting; but 

 another plague, not less disastrous, has attacked the cherry- 

 trees and plum-trees over several districts in France. 

 Great swarms of little animals resembling vine-fretters, but 

 which are not so in reality, established their habitati;'ns at 

 the extremity of the branches of the cherry-trees. As soon 

 as a branch was attacked, the leaves curled, and the juice 

 was dried up. On opening the leaf a considerable number 

 of ants was discovered, which, jointly with the insect vi^hich 

 began the ravages, sucked the branch, and made it wither. 

 What I have remarked is, that usually, when the vine-fret- 

 ters attack any tree, the neighbouring tree very soon expe- 

 riences the same fate ; but the attack of this year is only- 

 partial. In an alley of cherry-trees which I possess there 

 have seven been attacked, but not those which are next 

 each other. One tree was placed between two which were 

 very much damaged by these insects, and yet this one was 

 not hurt. 



On these vermin the smoke of tobacco had no effect at 

 all : this convinces me that they are difi'erent from the ordi-i 

 nary kind. 



Plum-trees, when attacked by the same insect, do not lose 

 their fruit like the cherry-trees; but the little animals cover 

 them with more rapidity, so as to extirpate even the appear- 

 ance of fruit. 



Having effectually watered a low plum-tree, I covered it 

 with ashes, in the manner we treat beans and cabbages, and 

 the vermin were destroyed : but this is only practicable with 

 a tree of low height. 



I mcide one remark, which I think is essential to commu- 

 nicate : it is, that plum-trees planted in ground which is not 

 necessarily watered, are less attacked by these insects than 

 those which have experienced a humidity communicated by 

 the plants in their neighbourhood, to which watering is ab- . 

 solutely iiecessary. I had one planted in a bed of arti- 

 chokes : we know very well that this plant requires plenty 

 of water ; and the tree was entirely covered with insects. Its 

 leaves withered^ and the fruit fell off"; while two other plum- 

 trees. 



