PLUM TREE WEEVIL. 



PLUM TREE WEEVIL. 



even; the wing-covers have several short 

 ridges upon them, those on the middle of the 

 back forming two considerable humps, of a 

 black colour, behind which there is a wide 

 band of ochre-yellow and white. Each of the 

 thigh's has two little teeth on the under side. 

 They begin to sting the plums as soon as the 

 fruit is set, and, as some say, continue their 

 operations till the first of August. After mak- 

 ing a suitable puncture with their snouts, they 

 lay one egg in each plum thus stung, and go 

 over the fruit on the tree in this way till their 

 store is exhausted ; so that, where these beetles 

 abound, not a plum will escape being punc- 

 tured. The irritation arising from these punc- 

 tures, and from the gnawings of the grubs 

 after they are hatched, causes the young fruit 

 to become gummy, diseased, and finally to drop 

 before it is ripe. Meanwhile the grub comes 

 to its growth, and, immediately after the fruit 

 falls, burrows into the ground. This may 

 occur at various times between the middle of 

 June and of August; and, in the space of a 

 little more than three weeks afterwards, the 

 insect completes its transformations, and comes 

 out of the ground in the beetle form. The 

 history of the insect thus far is the result of 

 my own observations; the remainder rests on 

 the testimony of other persons." 



In an account of the plum-weevil, by Dr. 

 James Tilton of Wilmington, Delaware, pub- 

 lished in the Domestic Encyclopedia, (article 

 Fruit,} and since republished in the " Georgi- 

 cal Papers for 1809" of the Massachusetts Agri- 

 cultural Society, and in other works, it is stated, 

 that peaches, nectarines, apples, pears, quinces, 

 and cherries are also attacked by this insect, 

 and that it remains in the earth, in the form 

 of a grub, during the winter, ready to be 

 matured into a beetle as the spring advances. 

 These statements, says Dr. Harris, I have not 

 yet been able to confirm. It seems, however, 

 to have been fully ascertained by Professor 

 Peck, Mr. Say, and others, in whose accuracy 

 full confidence may be placed, that this same 

 weevil attacks all our common stone-fruits, such 

 as plums, peaches, nectarines, apricots, and 

 cherries; Dr. Burnett has recently assured me 

 that he has seen this beetle puncturing apples ; 

 and it is not at all improbable that the trans- 

 formations of some of the grubs may be re- 

 tarded till the winter has passed, analogous 

 cases being of frequent occurrence. Those 

 that are sometimes found in apples must not 

 be mistaken for the more common apple- 

 worms, which are not the larvoe of a weevil. 

 The Rev. F. V. Melsheimer remarks in his ca- 

 talogue, that this insect lives under the bark 

 of the peach-tree. Professor Peck raised the 

 same beetle from a grub found in the watery 

 excrescence of a cherry tree, and from this 

 circumstance named it Rhyncheenus Cerasi, the 

 cherry-weevil. The plum, still more than the 

 cherry tree, is subject to a disease of the small 

 limbs, which shows itself in the form of large 

 irregular warts, of a black colour, as if charred. 

 Grubs, apparently the same as those that are 

 found in plums, have often been detected in 

 these warts, which are now generally supposed 

 to be produced by the punctures of the beetles, 

 and the residence of the grubs. Professor 

 918 



Peck says, that " the seat of the disease is in the 

 bark. The sap is diverted from its regular 

 course, and is absorbed entirely by the bark, 

 which is very much increased in thickness; 

 the cuticle bursts, the swelling becomes irre- 

 gular, and is formed into black lumps, with a 

 cracked, uneven, granulated surface. The 

 wood, besides being deprived of its nutriment, 

 is very much compressed, and the branch above 

 ihe tumour perishes." The grubs found by Pro- 

 fessor Peck in the tumours of the cherry tree, 

 went into the ground on the 6th of July, and on 

 the 30th of the same month, or 24 days from 

 their leaving the bark, the perfect insects began 

 to rise, and were soon ready to deposit their 

 eggs in healthy branches. 



In speaking of the difference between the 

 grub of the plum-weevil and apple tree cater- 

 pillar, Dr. Harris observes, " It must be borne 

 in mind that this plum-weevil, an insect un- 

 known in Europe, when arrived at maturity, is 

 a little, rough, dark-brown or blackish beetle, 

 looking like a dried bud, when it is shaken from 

 the trees, which resemblance is increased by 

 its habit of drawing up its legs and bending its 

 snout close to the lower side of its body, and 

 remaining for a time without motion and seem- 

 ingly lifeless. In stinging the fruit, before lay- 

 ing its eggs, it uses its short curved snout, 

 which is armed at the tip with a pair of very 

 small nippers ; and by means of this weapon 

 it makes, in the tender skin of the young plum 

 or apple, a crescent-shaped incision, similar to 

 what would be formed by indenting the fruit 

 with the finger-nail. Very rarely is there more 

 than one incision made in the same fruit; and 

 in the wound, the weevil lays only a single egg. 

 The insect hatched from this egg is a little 

 whitish grub, destitute of feet, and very much 

 like a maggot in appearance, except that it has 

 a distinct, rounded, light-brown head. By means 

 of the microscope I have satisfactorily ascer- 

 tained that the grubs from the fruit and from the 

 warts were exactly alike, and that both were 

 without feet. It appears, furthermore, that the 

 tumours on plum and on cherry trees are infested 

 not only by these insects, but also by another 

 kind of grub, provided with legs, and occasion- 

 ally by the wood-eating caterpillars of the JEgeria 

 exitiosa, or peach tree borer. When the grubs of 

 the plum-weevil are fully grown, they go into 

 the ground, and are there changed to chrysalids 

 of a white colour, having the legs and wings 

 free and capable of some motion ; and finally 

 they leave the ground in the form of little 

 beetles, exactly like those which had previously 

 stung the fruit. Further observation seems to 

 be wanting before it can be proved that the 

 cankerous warts on plum and cherry trees 

 arise from the irritating punctures of the plum- 

 weevils, and of the other insects that occasion- 

 ally make these warts their places of abode ; 

 although it must be allowed that the well- 

 known production of galls by insects on oak 

 trees and on other plants, would lead us to sup- 

 pose that those of the plum tree have a similar 

 origin. In addition to the means already re- 

 commended for preventing the ravages of 

 plum-weevils, I would observe that wall-fruit 

 can be perfectly secured by a screen of milli- 

 net or close netting, which should be put on as 



