Manual of Gardening Part 18

In all spraying operations it is especially important that the applications be made the very moment the insect or disease is discovered, or in the case of fungous diseases, if one is expecting an attack, it is well to make an application of bordeaux mixture even before the disease appears. When the fungus once gets inside the plant tissue, it is very difficult to destroy it, inasmuch as fungicides act on these deep-seated fungi very largely by preventing their fruiting and their further spread on the surface of the leaf. For ordinary conditions, from two to four sprayings are necessary to dispatch the enemy. In spraying for insects in home gardens, it is often advisable to make a second application the day following the first one in order to destroy the remaining insects before they recover from the first treatment.

There are many kinds of machines and devices for the application of sprays to plants. For a few individual specimens, the spray may be applied with a whisk, or with a common garden syringe. If one has a few trees to treat, however, it is best to have some kind of bucket pump like those shown in Figs. 221, 222. On a lawn or in a small garden a tank on wheels (Figs. 223, 224, 225) is handy and efficient. In such cases, or even for larger areas, some of the knapsack pumps (Figs. 219, 220) are very desirable. These machines are always serviceable, because the operator stands so near to his work; but as they carry a comparatively small quant.i.ty of liquid and do not throw it rapidly, they are expensive when much work is to be done. Yet, in ordinary home grounds, the knapsack pump or compressed-air pump is one of the most efficient and practicable of all the spraying devices.

For large areas, as for small orchards and fields, a barrel pump mounted on a wagon is best. Common types of barrel pumps are shown in Figs. 226, 227, 228. Commercial plantations are now sprayed by power machines.

There are many good patterns of spraying machines, and the intending purchaser should send for catalogues to the various manufacturers. The addresses may be found in the advertising pages of rural papers.

As to nozzles for spraying it may be said that there is no one pattern that is best for all purposes. For most uses in home grounds the cyclone or vermorel type (Fig. 233) will give best satisfaction. The pump manufacturers supply special nozzles for their machines.

[Ill.u.s.tration: Fig. 233. Cyclone or vermorel type of nozzle, single and multiple.]

_Insecticide spraying formulas._

The two cla.s.ses of insecticides are here described,--the poisons (a.r.s.enites and white h.e.l.lebore) for chewing insects, as the beetles and all kinds of worms; the contact insecticides, as kerosene, oils, soap, tobacco, lime-sulfur, for plant-lice, scale, and insects in such position that the material cannot be fed to them (as maggots in the underground parts).

_Paris green._--The standard insecticidal poison. This is used in varying strengths, depending on the insect to be controlled and the kind of plant treated. Mix the Paris green into a paste and then add to the water. Keep the mixture thoroughly agitated while spraying. If for use on fruit trees, add 1 lb. of quick lime for every pound of Paris green to prevent burning the foliage. For potatoes it is frequently used alone, but it is much safer to use the lime. Paris green and bordeaux mixture may be combined without lessening the value of either, and the caustic action of the a.r.s.enic is prevented. The proportion of the poison to use is given under the various insects discussed in the succeeding pages.

_a.r.s.enate of lead._--This can be applied in a stronger mixture than other a.r.s.enical poisons without injuring the foliage. It is, therefore, much used against beetles and other insects that are hard to poison, as elm-leaf beetle and canker-worm. It comes in the form of a paste and should be mixed thoroughly with a small quant.i.ty of water before placing in the sprayer, else the nozzles will clog. a.r.s.enate of lead and bordeaux mixture can be combined without lessening the value of either.

It is used in strengths varying from 4 to 10 lb. per 100 gal., depending on the kind of insect to be killed.

a.r.s.enite of soda and a.r.s.enite of lime are sometimes used with bordeaux mixture.

_White h.e.l.lebore._--For wet application, use fresh white h.e.l.lebore, 4 oz.; water, 2 or 3 gal. For dry application, use h.e.l.lebore, 1 lb.; flour or air-slaked lime, 5 lb. This is a white, yellowish powder made from the roots of the white h.e.l.lebore plant. It loses its strength after a time and should be used fresh. It is used as a subst.i.tute for the a.r.s.enical poisons on plants or fruits soon to be eaten, as on currants and gooseberries for the currant-worm.

_Tobacco._--This is a valuable insecticide and is used in several forms.

As a _dust_ it is used extensively in greenhouses for plant-lice, and in nurseries and about apple trees for the woolly aphis. Tobacco _decoction_ is made by steeping or soaking the stems in water. It is often used as a spray against plant-lice. Tobacco in the form of _extracts,_ _punks,_ and _powders_ is sold under various trade names for use in fumigating greenhouses. (See page 188.)

_Kerosene emulsion._--Hard, soft, or whale-oil soap, 1/2 lb.; water, 1 gal.; kerosene, 2 gal. Dissolve the soap in hot water; remove from the fire and while still hot add the kerosene. Pump the liquid back into itself for five or ten minutes or until it becomes a creamy ma.s.s. If properly made, the oil will not separate out on cooling.

For use on dormant trees, dilute with 5 to 7 parts of water. For killing plant-lice on foliage dilute with 10 to 15 parts of water. Crude oil emulsion is made in the same way by subst.i.tuting crude oil in place of kerosene. The strength of oil emulsions is frequently indicated by the percentage of oil in the diluted liquid:--

For a 10% emulsion add 17 gal. of water to 3 gal. stock emulsion.

For a 15% emulsion add 10 1/3 gal. of water to 3 gal. stock emulsion.

For a 20% emulsion add 7 gal. of water to 3 gal. stock emulsion.

For a 25% emulsion add 5 gal. of water to 3 gal. stock emulsion.

_Carbolic acid emulsion._--Soap, 1 lb.; water, 1 gal.; crude carbolic acid, 1 pt. Dissolve the soap in hot water, add the carbolic acid, and agitate into an emulsion. For use against root-maggots, dilute with 30 parts of water.

_Soaps._--An effective insecticide for plant-lice is _whale-oil soap._ Dissolve in hot water and dilute so as to obtain one pound of soap to every five or seven gallons of water. This strength is effective against plant-lice. It should be applied in stronger solutions, however, for scale insects. Home-made soaps and good laundry soaps, like Ivory soap, are often as effective as whale-oil soap.

_Miscible oils._--There are now on the market a number of preparations of petroleum and other oils intended primarily for use against the San Jose scale. They mix readily with cold water and are immediately ready for use. While quickly prepared, easily applied, and generally effective, they cost considerably more than lime-sulfur wash. They are, however, less corrosive to the pumps and more agreeable to use. They are especially valuable to the man with only a few trees or shrubs who would not care to go to the trouble and expense to make up the lime-sulfur wash. They should be diluted with not more than 10 or 12 parts of water.

Use only on dormant trees.

_Lime and sulfur wash._--Quicklime, 20 lb.; flowers of sulfur, 15 lb.; water, 50 gal. The lime and sulfur must be thoroughly boiled. An iron kettle is often convenient for the work. Proceed as follows: Place the lime in the kettle. Add hot water gradually in sufficient quant.i.ty to produce the most rapid slaking of the lime. When the lime begins to slake, add the sulfur and stir together. If convenient, keep the mixture covered with burlap to save the heat. After slaking has ceased, add more water and boil the mixture one hour. As the sulfur goes into solution, a rich orange-red or dark green color will appear. After boiling sufficiently, add water to the required amount and strain into the spray tank. The wash is most effective when applied warm, but may be applied cold. If one has access to a steam boiler, boiling with steam is more convenient and satisfactory. Barrels may be used for holding the mixture, and the steam applied by running a pipe or rubber hose into the mixture. Proceed in the same way until the lime is slaked, when the steam may be turned on. Continue boiling for 45 min. to an hour, or until sulfur is dissolved.

This strength can be applied safely only when the trees are dormant. It is mainly an insecticide for San Jose scale, although it has considerable value as a fungicide.

_Lime-sulfur mixtures and solutions for summer spraying_ are now coming to take the place of bordeaux in many cases. Scott's self-boiled lime-sulfur mixture, described in U. S. D. A. Bureau Plant Industry Circ. 27 is now a standard fungicide for brown-rot and black-spot or scab of the peach. Concentrated lime-sulfur solutions, either home boiled or commercial, are effective against apple scab and have the advantage of not russeting the fruit. Such concentrates, testing 32 Baume, should be diluted at about 1 gal. to 30 of water. Apply at same time as with bordeaux. Add a.r.s.enate of lead as with bordeaux.

_Fungicide spraying formulas._

The standard fungicide is bordeaux mixture, made in several forms. The second most important fungicide for the home gardener is ammoniacal copper carbonate. Sulfur dust (flowers of sulfur) and liver of sulfur (pota.s.sium sulfide) are also useful in dry or wet sprays for surface mildews. The lime-sulfur wash, primarily an insecticide, also has fungicidal property.

_Bordeaux mixture._--Copper sulfate, 5 lb.; stone lime or quicklime (unslaked), 5 lb.; water, 50 gal. This formula is the strength usually recommended. Stock mixtures of copper sulfate and lime are desirable.

They are prepared in the following way:--

(1) Dissolve the required amount of copper sulfate in water in the proportion of one pound to one gallon several hours before the solution is needed, the copper sulfate crystals being suspended in a sack near the top of the water. A solution of copper sulfate is heavier than water. As soon then, as the crystals begin to dissolve the solution will sink, keeping water in contact with the crystals. In this way, the crystals will dissolve much sooner than if placed in the bottom of the barrel of water. In case large quant.i.ties of stock solution are needed, two pounds of copper sulfate may be dissolved in one gallon of water.

(2) Slake the required amount of lime in a tub or trough. Add the water slowly at first, so that the lime crumbles into a fine powder. If small quant.i.ties of lime are used, hot water is preferred. When completely slaked, or entirely powdered, add more water. When the lime has slaked sufficiently, add water to bring it to a thick milk, or to a certain number of gallons. The amount required for each tank of spray mixture can be secured approximately from this stock mixture, which should not be allowed to dry out.

(3) Use five gallons of stock solution of copper sulfate for every fifty gallons of bordeaux required. Pour this into the tank. Add water until the tank is about two-thirds full. From the stock lime mixture take the required amount. Knowing the number of pounds of lime in the stock mixture and the volume of that mixture, one can take out approximately the number of pounds required. Dilute this a little by adding water, and strain into the tank. Stir the mixture, and add water to make the required amount. Experiment stations often recommend the diluting of both the copper sulfate solution and the lime mixture to one-half the required amount before pouring together. This is not necessary, and is often impracticable for commercial work. It is preferable to dilute the copper sulfate solution. Never pour together the strong stock mixtures and dilute afterward. Bordeaux mixture of other strengths, as recommended, is made in the same way, except that the amounts of copper sulfate and lime are varied.

(4) It is not necessary to weigh the lime in making bordeaux mixture, for a simple test can be used to determine when enough of a stock lime mixture has been added. Dissolve an ounce of yellow prussiate of potash in a pint of water and label it "poison." Cut a V-shaped slit in one side of the cork so that the liquid may be poured out in drops. Add the lime mixture to the diluted copper sulfate solution until the ferro-cyanide (or prussiate) test solution _will not turn brown_ when dropped from the bottle into the mixture. It is always best to add a considerable excess of lime.

_"Sticker" or adhesive for bordeaux mixture._--Resin, 2 lb.; sal soda (crystals), 1 lb.; water, 1 gal. Boil until of a clear brown color--one to one and one-half hours. Cook in iron kettle in the open. Add this amount to each fifty gallons of bordeaux for onions and cabbage. For other plants difficult to wet, add this amount to every one hundred gallons of the mixture. This mixture will prevent the bordeaux from being washed off by the heaviest rains.

_Ammoniacal copper carbonate._--Copper carbonate, 5 oz.; ammonia, 3 pt.; water, 50 gal. Dilute the ammonia in seven or eight parts of water. Make a paste of the copper carbonate with a little water. Add the paste to the diluted ammonia, and stir until dissolved. Add enough water to make fifty gallons. This mixture loses strength on standing, and therefore should be made as required. It is used in place of bordeaux when one wishes to avoid the coloring of maturing fruits or ornamental plants.

Not as effective as bordeaux.

_Pota.s.sium sulfide._--Pota.s.sium sulfide (liver of sulfur), 3 oz.; water, 10 gal. As this mixture loses strength on standing, it should be made just before using. It is particularly valuable for the powdery mildew of many plants, especially gooseberry, carnation rust, rose mildew, etc.

_Sulfur._--Sulfur has been found to possess considerable value as a fungicide. The flowers of sulfur may be sprinkled over the plants, particularly when they are wet. It is most effective in hot, dry weather. In rose houses it is mixed with half its bulk of lime, and made into a paste with water. This is painted on the steam pipes. The fumes destroy mildew on the roses. Mixed with lime, it has proved effective in the control of onion s.m.u.t when drilled into the rows with the seed.

Sulfur is not effective against black-rot of grapes.

_Treatment for some of the common insects._

The most approved preventive and remedial treatments for such insect pests as are most likely to menace home grounds and plantations are here briefly discussed. In case of any unusual difficulty that he cannot control, the home-maker should take it up with the agricultural experiment station in the state, sending good specimens of the insect for identification. He should also have the publications of the station.

The statements that are here made are intended as advice rather than as directions. They are chosen from good authorities (mostly from Slingerland and Crosby in this case); but the reader must, of course, a.s.sume his own risk in applying them. The effectiveness of any recommended treatment depends very largely on the care, thoroughness, and timeliness with which the work is done; and new methods and practices are constantly appearing as the result of new investigations.

The dates given in these directions are for New York.

_Aphis or plant-louse._--The stock remedies for aphides or plant-lice are kerosene emulsion and the tobacco preparations. Whale-oil soap is also good. The tobacco may be applied as a spray, or in the house as fumigation; the commercial forms of nicotine are excellent. (See page 194.) Be sure to apply the remedy before the leaves have curled and afford protection for the lice; be sure, also, to hit the underside of the leaves, where the lice usually are. The presence of lice on trees is sometimes first discovered from the honey-dew that drops on walks.

Usually the emulsion is diluted with 10-15 parts of water for plant-lice (see formula, page 194); but some of the species (as the dark brown cherry-leaf louse) require a stronger emulsion, about 6 parts of water.

The lady-birds (one of which is shown in Fig. 234) destroy great numbers of plant-lice, and their presence should therefore be encouraged.

[Ill.u.s.tration: Fig. 234. Lady-bird beetle; larva above]

_Apple-maggot or "railroad-worm."_--The small white maggots make brownish winding burrows in the flesh of the fruit, particularly in summer and early fall varieties. This insect cannot be reached by a spray as the parent fly inserts her eggs under the skin of the apple.

When full-grown, the maggot leaves the fruit, pa.s.ses into the ground, and there transforms inside a tough, leathery case. Tillage has been found to be of no value as a means of control. The only effective treatment is to pick up all windfalls every two or three days, and either to feed them out or to bury them deeply, thus killing the maggots.

_Asparagus beetle._--Clean cultural methods are usually sufficient to prevent the asparagus beetle's seriously injuring well-established beds.

Young plants require more or less protection. A good grade of a.r.s.enate of lead, 1 lb. to 25 gal. of water, will quickly destroy the grubs on the foliage of either young or old plants. Apply it with an ordinary sprinkling can, or better, use one of the numerous spraying devices now on the market. The necessity for treatment must be determined by the abundance of the pests. They should not be permitted to become abundant in midsummer or the over-wintering beetles may injure the shoots in the spring.

_Blister-mite on apple and pear._--The presence of this minute mite is indicated by small irregular brownish blisters on the leaves. Spray in late fall or early spring with the lime-sulfur wash, with kerosene emulsion, diluted with 5 parts of water, or miscible oil, 1 gal. in 10 gal. of water.

_Borers._--The only certain remedy for borers is to dig them out, or to punch them out with a wire. Keep the s.p.a.ce about the base of the tree clean, and watch closely for any sign of borers. The flat-headed borer of the apple works under the bark on the trunk and larger branches, particularly where much exposed to sun. The dead and sunken appearance of the bark indicates its presence. The round-headed borer works in the wood of apples, quinces, and other trees; it should be hunted for every spring and fall. On hard land, it is well to dig the earth away from the base of the tree and fill the s.p.a.ce with coal ashes; this will make the work of examination much easier.