Destruction of the Apple Crop hy Insects. 99 



the frosty nights in May." But that mere direct frost was not the 

 cause, seems proved by their own distinct statement, that tlie 

 bhght took place before the full expansion of the blossom, which, 

 it is well known, will bear a very severe cold before being unfolded. 

 From such observations as I have been able to make, I am strongly 

 inclined to suspect that the real cause of the " blight" is a pinkish 

 coloured Aphis, of which I have invariably found swarms in the 

 few leaves immediately surrounding the dead calyxes of the abor- 

 tive tufts of blossom, or their most abundant exuviae, when the 

 leaves being completely killed and blackened, were deserted for 

 more succulent pasture. Of their number an idea may be had 

 from the fact that on one single apple leaf at the base of a tuft of 

 dead blossom, I found nine pupse of Coccinella hipunctata, which 

 had evidently in their larva state found ample food from the 

 Aphides close to them. 



Now it is in this way that I conceive the mischief has been 

 done. The few leaves accompanying a tuft of apple blossom are 

 but half or one-third expanded when the blossom unfolds ; but 

 still there can be little doubt that they furnish the supply of sap 

 (whether in its first or elaborated state, the vegetable physiologists 

 must decide) which is to forward and complete the expansion of 

 the blossom. If, therefore, this sap be intercepted by numerous 

 Aphides just before the blossom is about to open, nothing can be 

 more likely than that the blossom should not expand at all, but 

 die and become abortive, as has actually taken place. And this 

 supposition seems strongly confirmed by what I have repeatedly 

 observed as to the fruit, viz. that whenever a single apple or 

 cluster of two or three, as are now and then seen, have ihe'ir full 

 size and a healthy aspect, they are always accompanied by healthy 

 and fully-expanded leaves, without any appearance on them either 

 of Aphides or their exuviae ; whereas in the cases, which also 

 occur occasionally, of one or more apples having survived in a 

 tuft whose leaves have been attacked by Aphides, they are in- 

 variably deformed and not one-fourth of their proper size — in fact, 

 mere abortions. Why the attacks of this Aphis have been so 

 much more general and fatal this year than usual, may, I think, 

 be explained by the very backward spring ; owing to which, 

 broods of young Aphides were hatched before the leaves were 

 out, and probably subsisted on the sap of the buds of the apple 

 trees, and were thus able in full force to assail the leaves the 

 moment they expanded, and at once drain them of all their fluid ; 

 just as I observed, this spring, the tinged buds of sycamores, a 

 full week or more before a single leaf was out^ to be covered 



