16 



EFFECTS OF LOCUSTS ON TREES, 



suffering in part from the Cicada, if he had 

 scraped the roots while uncovered, and 

 brushed them over with the soft soap, to 

 destroy the larva, not omitting the outside 

 process of ' heading back the top,' scraping 

 the bark, &c., that the third year would 

 have affbrded him three times six bushels 

 from the two trees. 



But I beg pardon for keeping you so long 

 from the article of Miss Morkis. Here it 

 is, verbatim et literatim : 



" I have for a number of years, believed 

 that the failure of fruit on trees over twen- 

 ty years old, was mainly owing to the rava- 

 ges of the larvae of the Cicada septemdeci?n, 

 though entomologists have heretofore con- 

 sidered them harmless, or nearly so, believ- 

 ing that the principal injury caused by them 

 was received on the branches of the trees 

 when depositing their eggs. But from the 

 fact of their burrowing into the earth the 

 moment of their escape from the eggs, and 

 their living, as all acknowledgCj on the sap 

 of the roots of plants, I was led to think 

 that the constant drain of sap required to 

 nourish so many thousands of grubs, of 

 from a quarter of an inch to an inch in 

 lengthj must be more than a tree could live 

 through) and yield good fruit. . I was con- 

 firmed in this opinion, by an experiment 

 made by J. B. W., New* York, and publish- 

 ed in the November number of the Horti- 

 culturist, page 227i The method prescribed 

 to renovate an outcast, is to dig a trench 

 four feet wide and twenty inches deep, 

 around the tree, leaving a ball of earth six 

 feet in diameter, and then to fill the trench 

 with rich earth and compost. The author 

 states that the experiment succeeded, and 

 that in three years the tree was in a flour- 

 ishing condition and yielded fine fruit. The 

 writer attributes the change to the new and 

 rich soil with which he supplied the tree. 

 I argue, that on cutting off the larvae of the 



Cicada, which he did when he cut off* so 

 large a portion of the roots, he removed the 

 real disease, and the tree was then in a 

 condition to take advantage of the congenial 

 soil placed around it ; and new life was 

 given to roots and branches. Under this 

 impression, I superintended a similar expe- 

 riment on a pear tree that had been declin- 

 ing for years, without any apparent cause, 

 and agreeably to my expectations, I found 

 the larv(B of the Cicada in countless num- 

 bers clinging to the roots of the tree, with 

 their suckers piercing the bark, and so deep 

 and firmly placed, that they remained hang- 

 ing for half an hour after being removed 

 from the earth. From a root a yard long, 

 and about an inch in diameter, I gathered 

 twenty-three larvse j they were of various 

 sizes, from a quarter of an inch to an inch 

 in length. They were on all the roots that 

 grew deeper than six inches below the sur- 

 face. The roots were unhealthy, and bore 

 the appearance of external injury from 

 small punctures. On removing the outer 

 coat of bark, this appearance increased, 

 leaving no doubt as to the cause of the dis- 

 ease. 



" The larves were enclosed in a compact 

 cell of earth, with no outlet except that in 

 immediate contact with the root, and as 

 there were no galleries or holes leading 

 from these cells, I infer that the grubs ne- 

 ver leave the roots they first fasten on ; 

 which may account for the great difference 

 of size : the small ones being starved spe- 

 cimens of the same brood ; though I am in- 

 clined to believe that there are two species, 

 differing sufficiently in size to account for 

 the discrepancy in the size of the larvas 

 now found. I noticed this difference in 

 1817, and again in 1834 : the note of the 

 smaller variety, or species, is much shriller 

 than that of the larger, and will never be 

 mistaken when noticed. 



