Guide to Growers.

Western Star, Issue 2253, 4 November 1898, Page 6

Guide to Growers.

TIIE_COI>L,IN ifIOTH » Life History. This destructive peat is a small brownish moth with a bronzy mark on upper wing. The female deposits her eggs in the calyx of the apple just when the fruit is newly formed, the fruit then being in an almost erect position, the time at which the eggs are deposited varying, of course, in different districts. The eggs are usually hatched in about four or five days, when the grubs commence eating into the fruit, and finally reach the pips in the centre, thereby causing a premature falling of the fruit and consequent decay. When full grown or nearly so the grubs, having eaten their way out of the truit, usually descend to the ground, or sometimes to the stem of the tree, but often remain in the fruit when fallen to the ground ; hence much of the danger in spreading the disease to other and probably clean districts. Having left the fruit the grubs iiibernate principally in the loose bark of the tree, and even in the soil below the stem of the tree, also in cases and other receptacles in which the infested fruit may be carried, this latter being a most important factor in the spread of the disease. As soon as the larva*, or grubs, are about to change into the cocoon stage, they spin a sort of web, and in this position remain until the chrysalid or final changing stage before the perfect insect makes its appearance, which it does some time previous to the flowering of the trees and when, as above stated, the newly-formed fruit appears the eggs are deposited, and so the work of destruction goes on. There appears even now to be doubts as to whether there is one or two broods of this insect, but certain it is that in some instances eggs are deposited on the face of the fruit, and in this case the destruction of the grub becomes more difficult, and, from experiments made in America, it is supposed that the moth from the late broods deposits its eggs also on the face of the fruit, the larvae remaining without undergoing any changes from early spring to January and even February. The moth I have reared from full-grown larvae in from fourteen to eighteen days. It may be mentioned that upon careful examination no difference whatever can be found between our Codlin Moth and that of Europe and America, so that it is only reasonable to suppoae the larvae to have been introduced through the agency of imported fruit or trees during the early days of the colony. Prevention and Remedies. In the case of any clean district all trees introduced from any other source whatever should be carefully looked over, especially those having any rough or loose bark attached, these being some of the principal hiding places for the grubs ; and such trees should at once be dipped according to the methods herein prescribed, viz. :—Tobacco water prepared in the proportion of 41bs. of refuse tobacco, 41bs. of soft soap, boiled in a gallon of water, with 50 gallons of water added ; and in this the trees should remain for thirty minutes, when they can be planted. AH fruit-cases which have been used, no matter from what quarter they may come, should be dipped in boiling water in a tank or other receptacle prepared for the purpose, and should there remain for five minutes, when they may be dried and stored for further use. Fruit cases, it may be remarked, being one of the most dangerous sources of spreading the infection, as in many hitherto clean districts the introduction of this pest may be traced to this cause, and a neglect which is certainly most reprehensible. At pruning time, or before it, treeßof apples, pears, often apricots, quinces, peaches, and even medlars as well, should be carefully examined, the loose or rough bark from the same scraped oil* and burned ; and for scraping off the bark, which should be removed as far up into the branches as practicable, a threecornered piece of iron fastened to a handle, or a slightly altered shipscraper, will answer the purpose admirably ; the object of removing the bark being to prevent the grubs from hibernating, as is their habit. Having removed and burned the bark proceed to apply the bands, which are artificial hiding places for the grubs, and from which they may be captured and destroyed. Bands may be made of pieces of gunny-bags cut into strips of, say, not less than 4 or 5 inches in width, and fastened around the stem and thickest branches of the tree, a piece of binding or other lasting twine being tied over the bands for the purpose of keeping them in position, the loose end of the band open at the lower end ; and should bagging not be available, coarse paper will partly suffice, although not being lasting it is more expensive and unsatisfactory than bands made of bagging. It is advisable to have two sets of bands, so that when the old ones are removed and dipped, as they should be in boiling water, their places can be taken by clean ones. All bands should be placed on the treeß before the time of flowering—in some districts about the end of November —and kept on the trees until no traces of the grubs can be found, the time varying in certain districts, but not earlier than April, and should be examined at least every three months, eßpocially during the time of hibernation. The band system, if properly carried out, being, perhaps, the most effective of all known methods of destroying the pest while in the grub stage, as also the cocoons. In addition to these precautions, spraying or painting the stem and thick branches of the tree with a strong kerosene emulsion might be practised ; and by doing this any grubs lurking in the forks of the tree might be destroyed. When spraying with kerosene emulsion allow the same to run down the stem into the ground to destroy stray grubs beneath the soil. All fruit bearing traces of the ravages of the grub—which is easily detected by the mass of dark-brown excreta of the larvce, which are pushed through the openings to the burrows—should at once be boiled or destroyed. As soon as the tree ha 3 shed its flowers and the young fruit is set, spray the tree with Paris green and lime—lib. of Blundell's Paris green in paste form, with lib. of lime to 180 to 200 gallons of water, the whole being well stirred and carefully strained may then be applied at intervals of about ten days, oftener in drier districts, three or four sprayings being sometimes necessary. All machines should be carefully cleaned after using. When spraying see that the mist is evenly distributed over the tree, thereby causing the poisonous liquid, which is perfectly harmless to human beings and stock, to run down and penetrate into the hollow cavity in the young fruit, thus destroying the newly-hatched grubs.