320 



JOURNAL OP HORTICULTURE AND COTTAGE GARDENER. 



[ December 28, 1872. 



animals both superior and inferior to them in the scale of 

 creation. 



During the present summer the larva of Blennocarnpa Cerasi 

 has been common in many places on the Cherry and Pear, 

 and also occasional on other fruit trees. Nor is it confined to 

 the orchard, for I have beaten specimens, which I take to be 

 this species, off the Oak. In several districts it has been 

 sufficiently numerous, small as are its proportions, to nearly 

 defoliate the trees, Iu its aspect it has quite the appearance 

 of a juvenile slug, and we can imagine a gardener shaking his 

 head with anger and vexation as he picked, or tried to pick, 

 one of these off a leaf, and soliloquising that things were 

 coming to a pretty pass when slugs took to travelling high up 

 on the branches of trees ; and with prophetic eye he perhaps 

 beholds them devouring fruit which has hitherto escaped their 

 attacks, however it may be exposed to other depredators. 

 This larva belongs to the Sawfly tribe, and matures into a 

 true winged insect, though so very molluscous in appearance 

 and in its mode of progression. Some one having asked the 

 editor of the " Entomologist " whether powdered hellebore was 

 effectual in exterminating it, that gentleman remarks patheti- 

 cally that it was difficult to know when you had purchased an 

 article by that name if it was what you required. The chemists 

 may be left to defend themselves in this matter. I presume, 

 though obliged to exercise much caution in the vending of so 

 poisonous a drug, they would scarcely dilute it wilfully to make 

 it less harmful. No doubt, however, the editor is right in 

 adding, that if hellebore is of service in the destruction of 

 Blennocarnpa Cerasi, the application of the remedy is not easy 

 to carry out. Handpicking, even when the larva; have attained 

 some size, would be troublesome and tedious, the insect hold- 

 ing so tightly as to squash in the fingers ere it be removed, 

 nor is it always within reach. The application of fumigants 

 would be more likely to answer, and compel the pest to double- 

 up and lose its hold. As yet the economy of the species is but 

 imperfectly known, and I hope to revert to the subject again 

 when I shall have been able to observe for myself the mode 

 of the deposition of the eggs. Many of the methods of killing 

 aphides, cocci, &c, would probably help to thin the numbers 

 of these little unsightly pests ; the nostrums sold in the form 

 of powder would be, I suspect, generally too expensive and of 

 no great efficacy. Lime thrown upon the trees in early summer, 

 at a time when they are not positively wet but rather damp, 

 has been suggested as likely to be useful. 



An enemy still better known both to the amateur and pro- 

 fessional grower of fruit is the insect called the American 

 blight, known in science as Aphis lanigera or Lachnus laniger, 

 also termed Eriosoma Mali. Like thieves with various aliases, 

 this circumstance does not prepossess us in its favour, and it 

 is certainly one of the most troublesome and annoying enemies 

 of the Apple : it is comparatively infrequent on the Pear. I 

 have not the means of ascertaining by statistics whether it 

 has been less common in England this season, but in some 

 places its propagation seems to have been considerably inter- 

 fered with by the rough weather we had in the second winter 

 or spring of 1S72. It is amusing how much interest has been 

 excited by the question as to where this insect came from if it 

 be not a native of this country. The ordinary appellation, of 

 course, throws the responsibility upon the new continent, 

 though there is no very strong evidence on the point, and we 

 could not get up even the outline of an "indirect claim" for 

 the injuries cur fruit trees have received. All, or nearly all, 

 that can be said is that Sir Joseph Banks saw an instance of 

 the ravages of this species at a nursery in Sloane Street in 

 1787, and fancied it had been imported from America. On 

 the other Eide, Mr. Salisbury avers that it came from Prance 

 in company with some refugees much earlier, and first located 

 itself at Paddington ; also he had been told by an old French 

 gardener that in the neighbourhood of Montpellier and else- 

 where this pest had been common for many years. No ! em- 

 phatically replies a French professor, the species came from 

 England to France about 1812, and about a dozen years after 

 that it travelled into Belgium. Then, again, we find the Ame- 

 rican pomologists declaring that they imported it from Europe 

 with some trees. After all, it seems very probable that this 

 blight is indigenous in each country mentioned, as though 

 instances have often occurred of an imported insect or plant 

 establishing itself, it has also happened that the arrival of a 

 species from abroad has brought to light the fact that it was 

 already a native of the country to which at first it was thought 

 to be a visitor. 

 When we investigate the economy of this insect, we see that 



in some particulars it is very much like an aphis, in others it 

 resembles a coccus. The winged males have quite an aphis 

 aspect, and, like those flies, they take excursions in the air 

 sometimes, the object of which is doubtful ; business rather 

 than pleasure, some think, who believe they are then preparing 

 for the continuance of the race. I am rather inclined to sup- 

 pose that they wander off thus after the work of impregnation 

 is completed. The downy females also travel from place to 

 place, becoming detached by the wind, and thus float on until 

 they effect a lodgment somewhere ; should it be on the branch 

 of a tree, then a new colony is soon established. This blight 

 usually rouses itself from its winter inactivity in March or 

 April, and if no measures have been taken against it during 

 the cold season, the first sign of its approaching ravages is a 

 peculiar hoariness, mostly about the old branches, in the cracks 

 or crevices of which some of the insects have* wintered. It 

 should be noted, however, en passant, that Eriosoma Mali does 

 not seem, in any stage of its growth, to be able to actually 

 penetrate old wood ; there must have been previously some 

 crack or wound where the insects are observed to be engaged 

 upon that. It is upon the wood of one or two years' growth 

 that they appear to employ themselves with most eagerness. 

 However, when they have once succeeded in establishing them- 

 selves in old wood, they will continue their destructive opera- 

 tions until branches are perforated, and even trunks. Huge 

 excrescences often arise through the effect of the numerous 

 punctures upon the alburnum. The secretion of sap is vitiated. 

 In bad cases the blight spreads until the tree dies from the 

 unhealthy action excited rather than from actual exhaustion of 

 its strength. In orchards matters may sometimes be allowed 

 to go on to this extent through inadvertence ; in gardens it 

 can scarcely happen if timely remedies are applied. By its 

 habits it is evident that this blight thrives most in hollows 

 and valleys, exposed trees often escaping. In autumn, too, 

 nature will occasionally work a cure upon infected trees and 

 shrubs, high winds and soaking rains dislodging multitudes 

 from their resting-places, when they are hurled through the 

 air until their downy investiture becomes their grave, unless a 

 sudden change in the weather enables them, or at least a part of 

 them, to reach a dry nook or crevice where, if they can fix them- 

 selves securely, the down serves to shield them from wet and 

 cold. This same secretion forms an admirable screen for the 

 young, which are exuded alive, and which have, like their 

 parents, a beak or rostrum, which is hidden under the breast, 

 and occasionally when not in use it is bent so far down as to 

 project beyond the abdomen as a point. If we separate a mass 

 of this downy substance (which it may be worth someone's while 

 to submit to a chemical analysis), we find usually amongst the 

 insects small ovoid or round bodies, which are not eggs but the 

 excretions of the blight ; and it does not appear that ants resort 

 to this so habitually as to the sweet secretion of the aphides. 

 Indeed, few other insects approach Eriosoma Mali with pur- 

 poses either friendly or hostile, so well is it secured by its 

 cottony robe, though the larva of a Dipterous insect, I believe 

 a species of Scasva, has been reported as a devourer of these 

 creatures. Nor are they eaten by birds, but it is possible they 

 may sometimes avail themselves of the down in their nest- 

 bunding. We cannot use it for anything, though we might 

 succeed in extracting a colouring matter from the insects 

 themselves. 



As already noted, this blight is to be observed in winter by 

 looking for it in sheltered angles of the trunk and branches, 

 and under loose bark ; but it is found also at that time about 

 the roots of the trees, to which it descends in the autumn. 

 Some writers recommend a careful watching about this season, 

 and an occasional removal of the earth about the roots. What 

 is carried away should be soused in water, and the fresh soil 

 afterwards in its turn. This may be done several times. 

 Where the blight is found to have actually attached itself to 

 the roots, if the trees are not too large they must be taken up 

 and cleansed, then replanted in different earth. With trees 

 of some size the soil may be taken up around, and the roots 

 exposed to a degree of cold — a sort of kill-or-cnre method. Or 

 the roots may be surrounded with a muddy compound, made 

 by the removal of a portion of the soil and stirring into the 

 remainder some ammoniacal liquor or strong soapsuds. It 

 may be added, that before betaking themselves to a subterra- 

 nean life the insects free themselves from a great part of their 

 cottony covering. 



What may be termed the general list of remedies is a pretty 

 long one, and yet some who have tried a variety of expedients 

 have been glad to come back to simple means ; and they have 



