THE ORCHARD

New Zealand Mail, Issue 1321, 24 June 1897, Page 5

THE ORCHARD

REMEDIES FOB IMSESTS 'AND

Fii^ei.

(Concluded.)

The following is from the r/jporfc of Mr C. W. Woodworth, of the Californian Agricultural Department:— SPRAYS OR WASHES.

The most important reme dies for plant pests are applied as a spray/ or wash. By the word wash one would 'naturally understand a more copious application than a spray, hut in ordinary usage the terms are identical.

For very low plants an outfit working on the principle of a sprinkling-can will do; but for better and more economical work, and work on higher plants, some form of force-pump aind spray nozzle is necessary.

There are many forms of pumps on the market that are good for the purpose. A good spray pump should maintain a fairly constant and sufficient pressure, and its; valves and general construeti«n should bo simple and its parts easily replaceable. The nozzle should, for most spraying work, be such as to break up the stream: into a fine mist; but for scale insects one giving a stream of considerable force is. desirable. The shape of the spray is tisually either conical or fan-shaped, and. each has its particular class of work.

The construction af the nozzle shoulcl be such as to permit of easy, quick, and thorough cleaning. A few forms designed to clean themselves automatically, work well.

In most spraying the object is to get the largest possible proportion of the spray to remain on the leaf or stem, and to have it well - distributed. This is best accomplished by covering the leaf with minute globules like dew. As soon as they run together and drip from the leaf the distribution is not perfect, and there is actually less left on the leaves.

When the nozzle is held as far from the plant as the steam will carry, the full effect of the nozzle is obtained in the breaking up the stream into mist, and so can produce most perfectly this dew - like condition.

For scale insects the object is somewl: .at different. The plan for these is. to thoroughly wet the surface of the foiark and the edges of the scale, to insure, the penetration of the wash beneath the scale, and thus to kill the old scale or the eggs and young hidden beneath. 1 i?his thorough wetting is secured by Stoic ling the nozzle close to the plant and appl; /ing a great deal of the wash with a high j iressure. "Washes are sometimes applied hot, and when the nozzle is held close to the plant the spray will penetrate better , and for this reason do better work. Heat is to be recommended as a remedy only when it can be absolutely controlled.

GRAIN SMUT. The method of treating seed wlie? it and oats for smut is as follows : For wheat, soak fifteen minutes in water at 182 deg. F. ; for oatw, ten minutes. The grain should first be placed in water at, say, USdeg., to partly warm it up. See ths/fc the grain is all wotted and do noV. treat too much at a time, or it wOi be impossible to keep the water at the proper temperature. Have boiling and cold water at hand, so as to add to keep the temperature just right. It mast not go above loodeg., or it may injure, the seed ; nor below lßOdeg., or it will not be effective. After treating, dip in cold water to cool, and spread out to dry.

BORDEAUX MIXTURE.

This is the most used and the most j satisfactory of the known washes for pre- ■ vention of fungus attacks. "When sprayed upon the plant it prevents the development of the spores of any fungi upon the surface covered ; and it is thus a perfect preventive of all the fungi which gain an entrance to the plant in this way. To be effective, it must be kept coiatinuously on the plant that is to be protected. A single spraying will last from two weeks to a month, or even longer if the conditions are favourable. With our dry summers one application will often be found enough for some kinds of fungi. Late spring rains may make additional spraying necessary ; and some fungi may, in some localities, require the repeated sprayings necessary in a more humid climate. Local experience will have to determine these points. i Bordeaux mixture is made of equal j parts of bluestone (copper sulphate) and lime. Some formulas give 6 parts of bluestone to 4 parts of lime, and will do if the lime is good. Slake the lime, and dissolve the bluestone separately. Both should be cold when they are mixed, and the re- j sultant mixture will be a beautiful blue wash. If mixed hot, a black compound (copper oxide) is produced, which reduces I the value of the wash, :

As to the a' jQ o unt of water, we recom- ! ] mend, for o r dinary spraying, 1 pound of | i each of tb/ d a b ove to 10 gallons of mix- I 3 ture ; an' j f or w i n ter use, 1 pound of each. I for 4 g^nons. COPPER CARBONATE. "'.his solution is very effectual, but is nr /t as lasting as the Bordeaux mixture. • A is a perfect solution, and therefore has no tendency to clog the nozzle (as is the ! case with the Bordeaux mixture), and can ' he used on fruit near the picking season, I and on ornamental plants, which would be disfigured with the lime wash. The usual way of making this wash is to dissolve copper carbonate in ammonia, and then dilute. If the carbonate is not fully dissolved before the water is added ib cannot be further dissolved, and not only is the carbonate wasted, but the fluid will not be up to standard strength. It is well, therefore, to give the ammonia ample time to act, say over night, before adding the water. The proportions are 1 ounce of the carbonate in 10 ounces of i ammonia for every 10 gallons on spray. Another way of producing the mixture ) is to mix solutions of bluestone and sal j sal soda, dissolving the carbonate of copper thus produced in ammonia, and diluting with water. The bluestone and the sal soda should be mixed in about the proportion of 3 to 4, after having been dissolved separately in a small quantity of warm water, and cooled before mixing. Three ounces of bluestone, with 4 of sal soda ancft 20 of ammonia is sufficient for 20 gallons of spray. j LISZK, SALT AND SULPHUR MIXTURE. I This wash is useful both as an insecti--5 cide and a fungicide, but only for winter use on deciduous trees. j It is -usually made by boiling the sulphur ' for one hour and a half with about onefourth of the lime, in a covered kettle, with enough water to cover well; then the res;t of the lime and the salt are I added, and the boiling continued half an hour longer. The proportions are about 6 pounds of lime, 2 of salt, and 3 of sulphur, for 60 gallons. RESIN SOAP.

The cheapest insecticide which kills by contact is resin soap. It is for scale 'insects, and so has good penetrating power. Like all insecticides killing by contact, the effect of the spray is soon gone, and it only kills the insects which . are wet with its spray. It is generally [j applied warm. k In making the soap, the ingredients are | placed in a close kettle with enough water [! to cover, and are boiled for two hours, i when all will be united into a soap. In [j following are diluting, only a little water j should be added at a time, and stirred in ; or, better, hot water should be used, because of the danger of chilling the soap and causing it to harden, when it is almost impossible to dissolve it again. fc The proportions are 8 pounds of resin, ) 2 pounds of standard caustic soda, and 1 c pint of fish oil for 40 gallons, for use on i trees in, foliage ; and the same for 25 to 30 s gallons for winter use.

KEROSENE. There has recently been placed on the market devices for mixing kerosene with water in the pump as it is being applied ; and with very good results. Full directions as to proportions accompany the device, and we will here only discuss the precautions to be observed. These are, chiefly, the use of a nozzle capable of producing a very fine mist; and applying the spray so that the drops do not run together, i.e., holding the

nozzle as far as possible from the plant, and not applying too much. I Pure kerosene has great penetrating power, perhaps the greatest of all the insecticides, and with the above precautions can be safely used.

KEROSENE EMULS'.ON

While not as cheap as resin soap, keroj sene emulsion is easier to make ; and, in j small quantities, or where the conveni- | ences for boiling are not at hand, is the I most satisfactory remedy. Like resin I soap, this spray only kills by contact. 1 The ordinary form of the emulsion is 3 something of an art to properly manuj facture. The ingredients are 2 parts of | kerosene to 1 of sour milk, or of strong I soap solution. The latter must be made I boiling-hot and added to the kerosene, ,' and the whole pumped through a spray nozzle for fifteen minutes. After pumpino- a few minutes the whole mass will become beautifully creamy and apparently perfectly emulsified; but if a little is placed in water it will be seen that some of the kerosene separates out and rises to | the surface. When the emulsion is perfect there will be no separation when diluted. If the soap is of poor quality or the water is hard, more soap must be ' used; and on the other hand, if both are good, not so much is needed as recommended below, which is intended to suit the average condition. ,

The proportions are 8 ounces of soap in 3 pints of water or sour milk, and 3 quarts of kerosene for 10 gallons of emulsion for I scale insects, or for 15 gallons for plantlice.

Another formula, which is easier made but more expensive, and so only recommended for use on a small scale, consists of using eight times as much soap. When so made, the creamy mixture described | above, obtained within five minutes, is a j permanent emulsion.

PARIS GREEN AND LONDON PURPLE.

These poisons kill only those insects that eat the leaves covered by them, and are useless against sucking insects like

plant-lice and scales. They are also useless against overwhelming numbers of insects, such as swarms of grasshoppers, which are able to eat up the plant before getting enough poison to kill them. Arsenic is the active principle in both these poisons, and is about equally strong in both. Paris green is copper arsenite, and London purple an arsenite of lime containing an aniline residue, to which the • purple colour is due. The latter is a finer' powder and remains better suspended inwater, but the Paris green is, as a rule,. safer to apply. Both poisons, if applied! too strong, will burn the foliage, and bothi. require constant stirring, or the material will settle to the bottom, and so not bs uniformly distributed. For the best results, the poison should not be allowed to drip from the tree, and the finer the spray the better.

These poisons do not as a rule remain any great length of time on the plant, but must be renewed every two or three weeks, or while the danger of insect attack exists. In mixing the poison it is well to first make a paste with a little water and then dilute, as otherwise it is difficult to wet the leaves with it. The amount used is about one ppund to twohundred gallons of water.