Apple Growing Part 5

In fighting it every scale must be destroyed or thousands more are soon born. In order to be able to use a strong enough mixture of lime and sulphur to destroy them by smothering or choking the spray must be applied on the dormant wood in the spring or fall or both.

Thoroughness is most essential.

7. THE OYSTER Sh.e.l.l SCALE, although it is essentially the same in its habits and in its methods of sucking the sap from the tree is not as bad a pest as the San Jose scale because it is less prolific, there being but one brood a year. Still this scale often destroys a branch and sometimes a whole tree. The "lice" winter as eggs under the scale and hatch in late May or early June. After crawling about the bark for two or three days, the young fix their beaks into it and remain fastened there for life, sucking out the sap. By the end of the season they have matured and secreted a scaly covering under which their eggs for the next season's crop winter. A smothering spray like lime and sulphur applied strong when the trees are dormant will practically control this scale. But the young may be destroyed in summer by a contact spray such as tobacco leaf extract or whale oil soap.

8. THE LEAF BLISTER MITE is a small, four-legged animal, so small as hardly to be visible to the naked eye. It pa.s.ses the winter in the bud scales and as soon as these begin to open in the spring it pa.s.ses to the tender leaves which it punctures, producing light green or reddish pimples according to the variety of apple. These later develop into galls or blisters of a blackish or reddish brown color and finally result in the destruction of the leaf. Trees are sometimes practically defoliated by this pest, and this at a time when a good foliage is most needed. Inside of the galls eggs are deposited and when the young hatch they burrow in all directions. In October the mites abandon the leaves to hibernate in the bud scales again. A strong contact spray of lime sulphur when the trees are dormant destroys the young mites while they are yet on the bud scales, which is practically the only time when they are vulnerable.

9. APHIDES, or plant lice, are of seasonal importance. Although nearly always present, it is only occasionally that they become so numerous as seriously to damage mature apple trees. But they are more often serious pests on young trees where they should be carefully watched.

Their presence is determined by the curled and distorted condition of the terminal leaves on the under side of which the green or pinkish lice will be found. Eggs deposited in autumn pa.s.s the winter in this condition, hatching in the spring about the time of the beginning of the growth of vegetation. From these winter eggs females are hatched which bear living young, which may also bear living young and so on for several generations until autumn, when eggs are again deposited for the winter stage.

Fortunately weather conditions together with parasitic and predaceous insects hold them more or less in check. Because of the difficulty of getting at the underside of the curled leaves where these lice mostly work they are extremely hard to control. Lime and sulphur when the trees are dormant destroy as many of the eggs as it comes in contact with. A tobacco extract is quite effective as a contact spray in the growing season. The trees must be closely watched and if the lice appear in any considerable number they must be promptly attended to or serious damage is likely to result.

These are by no means all the insect pests which the fruit grower has to combat, but they are usually the most important. Canker worm and tent caterpillars often do great damage in unsprayed orchards, but they are easily controlled by an application of a poison as soon as they appear. The same is true of other caterpillars and leaf eating worms. Apple tree borers are frequently serious, especially in young orchards, where the trees should be regularly "grubbed" and the borers dug out or killed with a piece of wire. They may be prevented to some extent by painting the tree trunks with a heavy lime and sulphur or some gas tar preparation.

DISEASES.--Although not as numerous as insects, the diseases which attack the apple inflict great damage and are fully as difficult to control. They are caused by bacteria and by fungi which may be compared to weeds growing on or in the tree instead of the soil. If either of these works within the plant, as is sometimes the case, it must be attacked before it enters. It is very necessary to be thorough in order to control these diseases. Weather conditions influence nearly all of them materially. Of those which attack the apple tree or fruit we have selected three as the most serious and the most necessary for the grower to combat, namely, (1) apple scab, (2) New York apple tree canker, and (3) fire blight. To these should be added in the South and middle lat.i.tudes, sooty blotch and bitter rot.

Baldwin spot is also frequently serious in some seasons and localities.

(1) THE APPLE SCAB, commonly known among growers as "the fungus," is the most important of our common apple diseases and is most evident on the fruit, although it attacks the leaves as well. In some seasons the fruit is made almost unsalable. This disease lives through the winter on old leaves. In the spring about blossoming time the spores are scattered by the wind and other agencies, and reaching the tender shoots germinate and enter the tissues of the plant. Their development is greatly dependent on the weather. In a season in which there is little fog or continued damp or humid weather, they may not develop at all, but where these conditions are present they frequently become very virulent.

Spraying will be governed by the weather conditions, but the mixture must be applied very promptly as soon as it is evident that it is likely to be necessary and must cover every part of the tree to be effective. The object is to prevent the spores from germinating, the spray being entirely a preventive and in no sense a cure. The disease most frequently first manifests itself on the tender new growth and on the blossoms. Two mixtures have been found to control it, namely, Bordeaux and a weak solution of lime and sulphur. One or other of these should be applied just before the blossoms open, just before they fall, and when necessary two and nine weeks later.

(2) NEW YORK APPLE TREE CANKER is usually found mainly on the trunks of old trees, but it also affects the smaller branches. Practically every old or uncared for orchard has more or less of this canker, and where it is not checked it eventually destroys the tree. This fungus is the cause of most of the dead wood found in old orchards. The surface of the canker is black and rough and covered with minute black pimples. It lives over winter and spreads from one branch or tree to another. As it most frequently enters a branch through wounds made in pruning, these should be promptly painted over with a heavy lead and oil paint. All diseased parts should be cut out and removed as soon as observed. The value of spraying for this disease is not definitely known, but it is seldom very troublesome in well sprayed and well cared for orchards.

(3) BLIGHT appears on apple trees in three forms, as blossom blight, as twig blight, and as blight cankers. It is a bacterial disease which is distributed by flies, bees, birds, etc., and cannot be controlled by spraying. The bacteria are carried over the winter in cankers on the main limbs and bodies of the trees, oozing out in a sticky ma.s.s in the spring. These cankers should be cut out with a sharp knife cutting well into the healthy bark and then washing the wound with corrosive sublimate, one part to one thousand of water.

Cutting out and destroying are also the chief remedies to be used when the blight appears in the twigs and blossoms. It is not usually as serious on apples as on pears. Some varieties, like Alexander, are more subject to it than others.

CHAPTER VIII

THE PRINCIPLES AND PRACTICE OF SPRAYING

The spraying of fruit trees in the United States is of comparatively recent origin, having been a general commercial practice for less than two decades. It involves the principle of applying with force and in the form of a fine rain or mist, water in which a poison or a substance which kills by contact is suspended. The first application of the principle was against chewing insects with h.e.l.lebore. Pure a.r.s.enic was early used and soon led to the use of other a.r.s.enicals.

Our greatest fungicide, Bordeaux mixture, was discovered by accident in 1882 when it was found to control mildew in France. Up until about five years ago Bordeaux mixture as the fungicide and paris green as the poison were almost universally used. Within the last few years, however, there have been developed two subst.i.tutes which, although known and used to some extent for twenty years, have only recently come into such general use as practically to replace the old sprays.

These are lime and sulphur as the fungicide and partial insecticide and a.r.s.enate of lead as a partial insecticide.

The necessity for and the advisability of spraying have already been pointed out. There is an increasing demand for fine fruit the supplying of which is possible only with thorough spraying. In the humid East especially the compet.i.tion of more progressive sections in the West is demanding more and better spraying. There is no cure-all in this process. It does not make a tree more fruitful except as it improves its general health, but it does bring a larger percentage of the fruit to perfection. Certain knowledge is fundamental; the grower must know what he is spraying for, when and with what to combat it and how to accomplish the desired result most effectively.

Spraying is an insurance against antic.i.p.ated troubles with the fruit, and the best and most successful growers are those most completely insured. It has many general advantages also. It stimulates the grower to a greater interest in his business because of the extra knowledge and skill required. It compels thoroughness. It necessitates spending money, therefore a return is looked for. To be sure, it is only one of the operations necessary to success, but it enables us to grow a quality of fruit which we could not obtain without it.

SPRAY MATERIALS are conveniently divided into two cla.s.ses, insecticides and fungicides. An insecticide is a poison by which the insect is killed either directly by eating it, or indirectly by the caustic, smothering, or stifling effects resulting from closing its breathing pores. Direct poisons are used for insects which eat some part of the tree or fruit and are called stomach poisons. Sprays which kill indirectly are used for insects which suck the sap or juice from the tree or fruit and are called contact sprays. a.r.s.enical compounds have supplanted practically all other substances used to combat external biting insects. Two stomach poisons are commonly used, namely, a.r.s.enate of lead and paris green, but the former is rapidly replacing the latter.

a.r.s.eNATE OF LEAD is prepared by mixing three parts of crystallized a.r.s.enate of soda with seven parts of crystallized white sugar (acetate) of lead in water, but it will not as a rule pay the grower to mix his own material, as a.r.s.enate of lead can be purchased in convenient commercial form at a reasonable price. The preparation on the market is a finely pulverized precipitate in two forms, one a powder and the other a paste. These are probably about equally good and are readily kept suspended in water. Less free a.r.s.enic is contained in this form than in any other compound of a.r.s.enic, making it safer to use, especially in heavy applications. a.r.s.enate of lead may be used without danger of burning the foliage as strong as five or six pounds to fifty gallons of water, but three pounds is the usual and a sufficient amount for the control of any apple insect for which it is efficacious.

PARIS GREEN is being rapidly displaced by a.r.s.enate of lead for several reasons. It is a compound of white a.r.s.enic, copper oxide, and acetic acid. The commercial form is a crystal which in suspension settles rapidly, a serious fault. It is more soluble than a.r.s.enate of lead and hence there is greater danger of burning the foliage with it.

Moreover, it costs from twenty to twenty-five cents a pound, and the a.r.s.enate of lead can be purchased for from eight to ten cents a pound.

The amount which it is safe to use in fifty gallons of water is from one-half to three-quarters of a pound. When paris green is used alone as a poison lime should be added. Both these a.r.s.enicals should be thoroughly wet up by stirring in a smaller receptacle before they are put into the spray tank, in order to get them in as complete suspension as possible. They may be used in the same mixture with Bordeaux or lime sulphur.

CONTACT SPRAYS.--Four compounds are used as contact sprays in combating sucking insects, namely, lime sulphur, soaps such as whale oil soap, kerosene emulsion, and tobacco extract. Of these lime sulphur is the most used and for winter spraying is probably the best.

This preparation is made by boiling together for one hour or until they unite, twenty pounds of quick lime, fifteen pounds of flower of sulphur, and fifty gallons of water. Although the home made mixture is much cheaper than the commercial form which may be purchased on the market, many people prefer the latter because of the inconvenience and trouble of preparing the mixture, although there is nothing difficult about it.

This contact spray is used chiefly for the San Jose scale and the blister mite, and in order to control these must be applied strong on the dormant wood. The strength necessary will vary from one part of the mixture above mentioned or of the commercial preparation, to from seven to ten parts of water, according to the density test of the material, which should be around twenty-eight per cent. Beaume (a scale for measuring the density of a liquid) for home made, and thirty-two per cent. for the commercial mixture.

Any good soap is effective in destroying soft bodied insects such as plant lice. The fish oil soaps, although variable in composition, are often valuable, especially the one known in the trade as whale oil soap. This soap dissolved in water by boiling at the rate of two pounds of soap to one gallon of water, makes a good winter spray for scale but should be applied before it gets cold as it is then apt to become gelatinous. For a summer contact spray against lice, one pound of soap to seven gallons of water is strong enough to be effective. It is objectionable because of its odor and because it is disagreeable to make and handle. Lime sulphur is to be preferred as a winter spray, but the soap spray is often necessary and valuable for summer sucking insects.

Kerosene emulsion was formerly more commonly used than now against the scale and plant lice. It is a mixture of one-half pound of soap and two gallons of kerosene in one gallon of water--preferably in hot water. For dormant trees one gallon of this mixture should be diluted with six gallons of water. While this spray is effective it is no more so than lime-sulphur and is quite difficult and disagreeable to handle. As a summer spray, however, it is often necessary. Several preparations of petroleum known as the miscible oils are sometimes used. Their use is the same as that of lime-sulphur and they are not as good.

Within the last few years a tobacco concoction known as black leaf tobacco extract (nicotine sulphate) has come into quite common use. It can be purchased commercially under various brand names, and should be diluted according to its strength, but usually about one part to fifty of water. It may be made by boiling one pound of good tobacco stems in two gallons of water for one-half-hour. Objections to it are that it evaporates very quickly, although it is supposed to be non-volatile, and that it is expensive, but it is very convenient to use, can be readily mixed with other summer sprays, and is very effective against plant lice and mites.

BORDEAUX MIXTURE. Fungicides are mixtures of chemical compounds made up for the purpose of controlling plant diseases caused by a cla.s.s of plant weeds known as fungi. There are three commonly well known and used fungicides, Bordeaux mixture, commercial lime sulphur, and the self-boiled lime-sulphur. The Bordeaux mixture is the best all-around fungicide known. It is a mixture of three pounds of copper sulphate (blue vitriol or bluestone) with three or more pounds of fresh burned stone lime in fifty gallons of water. The two compounds should be put together as fruit growers say "with water between," that is each should be diluted with the water separately before the two are mixed.

The best plan is to have stock mixtures of each in barrels, fifty gallon cider or vinegar barrels making good receptacles for the purpose. Place the bluestone in an old fertilizer or meal sack and suspend it about midway in the barrel of water. In a few hours it will all be dissolved and will remain in suspension for some length of time very well. If say fifty pounds of the copper sulphate are dissolved in fifty gallons of water, each gallon of water will contain one pound of the bluestone, which makes a very convenient way to measure it. So also fifty pounds of fresh burned stone lime should be placed in a barrel--in this case in the bottom of the barrel rather than in a sack--just covered with water and allowed to slake, more water being added as required up to fifty gallons. If too much water is added to the lime at the first it will be "drowned" and its slaking checked.

These two stock mixtures, each gallon containing one pound of the copper sulphate or one pound of the lime, are then mixed together.

It is well to fill the tank about half full of water, then put in the required amount of the copper sulphate, and after stirring well add the lime milk. It is a good plan to add an excess of lime as it minimizes the danger of burning and aids the mixture in sticking to the leaves well. If one is sure that he has at least as much lime, or an excess of lime, it will not be necessary to test the mixture, but if he is not, a simple test may be made with ferro-cyanide of pota.s.sium, obtained at a drug store. A few drops of this mixture will disappear if the lime is equal or in excess of the copper sulphate, that is, it will be neutralized, but if it is not, they will remain a bright purplish red. Bordeaux mixture is used in strengths varying from three to five pounds each of bluestone and lime in fifty gallons of water, but the former is usually sufficient.

LIME-SULPHUR.--The more important fungicides, the commercial lime sulphur and the self-boiled lime-sulphur, are practically superseding Bordeaux as a fungicide, not because they are necessarily better, but because there is frequently much burning of the foliage and russeting of the fruit from the use of the Bordeaux. This is unfortunate as the latter is a rather more effective fungicide as well as more convenient and pleasant to use. The self-boiled lime sulphur is a combination of lime and sulphur which is boiled by the heat of the slaking lime alone, and makes a pretty good subst.i.tute for the Bordeaux when it injures foliage or fruit. This preparation of lime and sulphur differs from the commercial form used as a winter wash in that it is wholly a mechanical mixture and not partly chemical like the latter. It may therefore be used on the foliage in summer at a greater strength, there being only a very small percentage of sulphur in solution when the mixture is properly made.

Equal amounts of lime and sulphur are used, these being from eight to ten pounds each to fifty gallons of water. The mixture is best prepared in larger quant.i.ties so as to get heat enough from the slaking lime to produce a violent boiling for a few minutes. First, place say forty pounds of lime in a barrel and pour on just water enough to start it slaking nicely--about a gallon to each three or four pounds of lime is usually sufficient. Then add the sulphur and enough more water to slake the paste, keeping it well stirred meanwhile. The violent boiling of the lime in slaking will cook the mixture in from five to fifteen minutes, depending on the quality of the lime and how fast it is slaked. Just as soon as the violent boiling is over add enough cold water to stop all action. If this is not done, some sulphur will unite with the lime and burning may be the result.

This self-boiled mixture is entirely harmless to apple foliage and even appears to have a stimulating effect upon it. Against the apple scab, however, it is not as effective as the boiled wash, or the commercial preparations. For this disease a strength of from one to thirty to one to forty (that is about one and one-half gallons of the prepared mixture testing 31 to 33 Beaume to fifty gallons of water) of the commercial lime-sulphur is most effective.

SPRAY PUMPS.--The application of the foregoing spray mixtures is fully as important as the sprays themselves, for on the right application at the right time depends the efficacy of the spray. For this purpose a considerable amount of special machinery has been devised. Lack of s.p.a.ce prevents us from going into much detail on this question, so we must be content with merely outlining the different types of machines and mentioning their accessories. Sprays are forced through single, double or triple acting pumps, either by hand or power. The three types of power available are traction, compressed air, and gasoline, the last being the most used. Steam power is practically obsolete.

The knapsack is the simplest type of hand pump, but it is of no practical use in the mature apple orchard. For small orchards and small trees several types of hand pumps are quite effective. The lever type of pump, where the handle is pushed from and pulled toward the operator, probably gives the most power with the least tiring effect, because it enables one to use the weight of the body to some extent.

It is best not to have the pump attached to the spray barrel or tank, but set on a movable base of its own, as then it can be used for any one of a number of barrels. Such an outfit may be obtained for from twenty-five to forty dollars.

It is well to buy a standard make of pump, preferably from a nearby dealer, so that repairs may be readily secured. For all orchards up to three or four acres in size, and for larger orchards where the trees are not over twelve or fifteen feet in height, this kind of spray rig is the most practicable and advisable, when the expense is taken into consideration. This applies especially to the general farm.

The power of a traction sprayer is developed from the wheels. There is much discussion as to whether sufficient power to throw an effective spray can be supplied by this method. By acc.u.mulating considerable pressure by extra driving at the ends of the rows and then skipping every other tree in order to keep up the pressure, going over the rows twice, a very satisfactory pressure can be obtained for trees which are not too large. The argument for this type of machine, and it is especially applicable on the general farm, is that it can be used for other spraying on the farm as well as for the apple orchard, especially for potatoes and small fruits. It is a comparatively cheap type of power, particularly when it can be used for several purposes.

The compressed air gas sprayer comes next in point of simplicity and cost for a power sprayer. Its most economic use is found where orcharding is carried on extensively enough to pay to compress the air or gas right in the orchard. This is of course impracticable on the general farm. Therefore the air or gas must be purchased and shipped to the farm in steel tubes. This often causes delay at critical times and is rather expensive. Moreover, the gas is open to the objection of interfering with the lime-sulphur compound by precipitating some of the sulphur.

The gasoline engine is the most useful and popular type of power for the orchard sprayer, as well as for general use on the farm. Many makes are now so perfected that they give little or no trouble. One and a half or two horsepower are fully sufficient for spraying, but most farmers prefer from three to five horsepower in order to be able to use the engine more for other purposes. The latter power is open to objection for spraying purposes on account of its weight, as especially in early spring it is very difficult to haul so heavy a rig over the soft ground. Such an outfit is also rather expensive.

Standard makes of gasoline engines of sufficient power for spraying cost from $75.00 to $150.00 according to horsepower and efficiency.

For very large trees, for mature orchards, and for all orchards larger than four or five acres, the gasoline engine is the best source of power for spraying, particularly where it can be used for other purposes on the farm.

A double acting or two cylinder pump is most desirable. If there is plenty of power a triplex or three cylinder pump is still better. The requirements of a good pump are: sufficient power for the work desired of it; strong but not too heavy; fewest possible number of parts consistent with efficiency; bra.s.s parts and valves; and a good sized air chamber. A number of standard makes of pumps answer these conditions very well. Pumps should always be washed out with clean water when the operator is through with them and the metal parts coated with vaseline. Never leave water in a pump chamber or in the engine jacket in cold weather.

The ordinary hand pump and barrel give satisfactory use when placed on a wagon, unless the trees are very high. But for large orchards, high trees, and where larger tanks and power pumps are used it is desirable to have a special truck for the outfit. The front wheel should be made low so as to turn under the tank to enable the driver to make short turns around the trees. A tower is desirable where high old trees are to be sprayed. This should be substantial but as small as is consistent with the purpose so as not to catch on the limbs and make it difficult to get close up around the trees. The height of the platform must be regulated by the need and by the roughness of the ground. On steep side hills the wagon body on which the tank rests should be underslung.

In order to get as near to the work as possible get a long hose--from twenty to thirty feet according to circ.u.mstances. The best quality, three to five ply, is none too good. Hose should be three-eighths to one-half inch in diameter, one inch being too heavy. Extension rods are a practical necessity. They should be ten to twelve feet long and made of bamboo lined with bra.s.s, that is, as light as possible.

Nozzles are very important in thorough and effective spraying. There is no best nozzle, nor one with which all the work can be done.

Several things should be considered in selecting a nozzle. First of all, it must be of convenient form so as not to catch in trees and so constructed that it will not clog easily. Second, for apple trees it should have good capacity and deliver as spreading a spray as possible. Third, the nature of the spray is very important.

Insecticides should usually be applied with force in a comparatively coa.r.s.e driving spray, but fungicides should be applied in a fine mist or fog so that they will settle on every part of the tree. Therein lies the difficulty of applying insecticides and fungicides together.