INSECT PESTS

All affected parts on smaller branches should be cut back to healthy wood, while on the main branches or trunk, where only a small portion or one side is affected, it is best to clean out the dead bark and paint the bared wood with a protective covering until new bark can cover the spot. At the same time every effort should be made to remedy the soil-moisture conditions which were largely responsible for the trouble in the first place.

Fruit-drop.—The same conditions which cause sour-sap may cause fruit drop. It may be caused by lack of pollination due to improper mixing of varieties or to rain during blossoming. Frost may also produce the same thing by killing the germ in the young fruit. In such cases, the fruit may remain on the tree for one or two weeks after the injury occurs before falling, and in some cases, may even appear to continue its development for a short while.

Mites.—Commonly called red spiders. There are two kinds of mites that do much damage in almond orchards, the brown or almond mite and the yellow or two-spotted mite. Both are common in all parts of the state and are the worst pests the almond grower must regularly face.

The brown mite (Bryobia pratensis) is the larger of the two, is dark red or brown in adult stage, has very long front legs, and a flattened back. It does not spin any web and works on the green bark of the small twigs as well as on the leaves, sucking the plant juices from beneath the bark. It causes a mottling of the leaves which eventually fall, although not as readily or in such large numbers as when attacked by the yellow mite. The injury to the tree is equally as great because of the serious drain on the vitality as a whole and because it commences work earlier in the season. This mite may spend its entire life on the tree; the very small, round, red eggs being laid largely on the under-side of the branches and in cracks and crevices in the bark and twigs. These remain on the tree throughout the winter and hatch early in the spring soon after the trees have their leaves half developed, leaving the white egg-shells in place. Most of their work is done in the spring and early summer.

Fig. 22.—Nonpareil almonds. Branch on left free from Red Spider and holding its full supply of leaves in green, healthy condition; branch on right defoliated by Yellow Mite. Note premature ripening of nuts on defoliated branch.

Fig. 23.—Forty-three-year-old Languedoc almonds on peach root, near Davis. This orchard has not been thoroughly cultivated or irrigated. Mites have largely defoliated the trees. See contrast inFig. 24.

The brown mite may be controlled satisfactorily by means of a dormant spray of lime-sulphur solution, 1 gallon to 10 gallons of water, applied just before the buds open in the spring. Crude oil emulsion as a dormant spray is also effective, if thoroughly applied over the entire tree under high pressure. This also applies to applications of the lime-sulphur spray.

During the growing season a milder material must be used. Dry dust sulphur, using only the very finest grade of “flowers of sulphur,” is often very effective, provided weather conditions are satisfactory, but generally this must be applied a number of times if best results are to be obtained. The work is done by blowing the sulphur dust into the tree with blowers in the early morning when there is little or no wind.

A more satisfactory method is the use of “Atomic sulphur” or other sulphur pastes or similar material. “Atomic sulphur” is a prepared spray whose value consists in the fact that the sulphur is held in suspension in water so that it may be applied as a liquid spray. By this method the material may be more effectively and thoroughly applied. “Atomic sulphur” is applied at the rate of 10 pounds to 100 gallons of water.

Fig. 24.—Forty-three-year-old Languedoc almonds on peach root, near Davis. This orchard has been irrigated and thoroughly cultivated, and mites have not defoliated the trees. Note contrast inFig. 23.

The use of lime-sulphur, the commercial strength of 33 to 34 degrees Beaumé being diluted 1 part to 35 parts water, is another effective method. For such use a flour paste may be added at the rate of 4 gallons to each 100 gallons of the spray mixture to act as a spreader. This paste is made by cooking one pound of flour with enough water to make one gallon of the mixture.

The yellow mite (Tetranychus telarius) is much smaller than the brown mite and is of a pale yellow color with occasionally a reddish tinge and sometimes with two darker spots on either side of the body. Unlike the brown mite, the winter is spent in concealment somewhere, presumably off the tree. During the warm days of early summer,generally in June, the mite makes its appearance on the trees, spinning a fine web on the leaves, generally on the upper surface, and then works under this web. The mite sucks the plant juices from the leaves giving them a yellowish mottled appearance. These leaves soon die and drop to the ground. In serious infestations the trees are often almost completely defoliated by the end of August. (Seefigure 22.)

The use of dormant sprays is not effective for controlling the yellow mite, but the summer sprays mentioned above are all satisfactory, and for best results, must be applied under high pressure, preferably 200 pounds or more.

The mites are much easier controlled where a comparatively high percentage of moisture is kept in the soil by frequent cultivations, or, if necessary, by irrigation (figures 23 and 24).

Peach Twig Borer(Anarsia lineatella).—In the larval stage these borers work on the young buds and shoots in the early spring. They are especially troublesome in newly planted orchard trees when a comparatively small number may kill most of the new shoots which are needed to make the desired framework of the tree. In some years they may be serious in large trees also. Dormant spray of lime-sulphur applied under high pressure just as the buds are opening in the spring will control the borers very effectively. This same spray may be used to control the brown mite, thereby accomplishing double control.

California Peach Borer(Ægeria opalescens).—The larvae are serious in many parts of the state where they burrow just under the bark near the surface of the ground. They may be detected by the small bits of frass and gum at the entrance of their burrows. If allowed to continue, they will eventually girdle the tree.

The surest means of control is to dig out the worms with a knife or kill them with a wire probe. This work should be done systematically once or twice every year and very thoroughly if it is to be effective. The application of hot “Flotine” or asphaltum, grade D, after the worms are killed should help considerably to prevent the entrance of the larvae. To be effective it must be applied at least twice a year on young trees and probably the same on old trees.

Thrips.—These are most serious on the almond leaves, their attacks being serious enough to cause considerable defoliation in late spring or early summer. They may be controlled by spraying with lime-sulphur, 1 to 30, to which has been added black-leaf 40 (40 per cent nicotine) at the rate of 1 part to 1500 parts of water or other spray-mixture. It is possible that other than the pear thrips have beendoing damage, but the same spray as described above should be effective against all.

Grasshopper.—Grasshoppers have been serious in orchards in outlying foothill districts in some years, and especially so in young orchards where it has been almost impossible to get trees started properly. In such locations special means must be employed on a large scale to protect orchards from their devastations, of which poisoned bait and hopper dozers are the most effective.

Fig. 25.—Almonds infested with larvae of Indian Meal Moth (Plodia interpunctella).

Indian Meal Moth (Plodia interpunctella).—The larva of this moth feeds on the kernels of the harvested almonds when they are stored. Infestation usually takes place in storerooms or warehouses in which the nuts have been placed for a time. The warehouses become infested from old grain bags which have been kept there at one time or another. So far as known, infestation does not take place in the field. The larvae will continue to work in the stored almonds for a long time, doing a very great amount of damage (fig. 25). They may be controlled by thoroughly cleaning out the corners of the warehouse and thoroughly disinfecting. The nuts should be disinfected with carbon bisulphide (explosive when in the form of a gas mixedwith air), or other means used to control insects in grain.[6]Prevention is far easier than the cure in this case.

Scale, aphis, diabrotica and other insects are sometimes found on the trees, but are generally not sufficiently troublesome to require special attention. Most of them are held in check by the control measures used for the more serious pests.

Gophers.—These often do great damage to the trees by girdling them just below the surface of the ground, or if they do not actually girdle the trees, they cut them enough to devitalize them and, in addition, the wounds made by their gnawings frequently become infected with crown-gall organisms. The only safe means of control is the constant use of traps supplemented by poisoned bait.

Squirrels.—Squirrels are very troublesome, as they harvest a large amount of almonds before they are sufficiently ripe to be harvested by the grower. The use of poisoned grain or “gas,” if used over a large area of surrounding territory, will prevent serious depredations.

Birds.—Birds also carry off large amounts of almonds if the orchards are near open country or hills, especially if wooded. Crows, bluejays, blackbirds, yellow-hammers, robins and other similar birds are the worst offenders. Sometimes linnets eat off large numbers of fruit buds in the spring in a few of the newer sections where plantings are scattered. Sap-suckers have been known to girdle entire trees or large branches by cutting large numbers of holes in a series of lines close together around the trunk or limbs.

Morning-glory.—This is probably the worst of the weeds in almond orchards, and is the hardest to control. Sheep and chickens may be used with excellent results, provided care is taken to see that the sheep are not allowed to go hungry, for then they will bark the trunks of the trees very quickly. An excellent plan is to arrange gates so that the sheep must go through the orchard from pasture to get water. In passing back and forth they will forage over the entire orchard and dig up all the morning-glory in sight. Chickens are fond of the succulent new shoots, and will keep them below the ground until the underground stems and roots weaken and die. Cultivation throughout the growing season, often enough to prevent the morning-glory from developing any leaves for a whole year at least, and longer if necessary, will starve the plants to death.

The problem of selecting varieties of almonds for planting in California is to choose the ones that are most marketable and at the same time to secure best results in cross-pollination. At the present time there are comparatively few varieties of almonds which have won and retained their popularity with the grower and the trade. There are a number of reasons for this condition. The cultural, climatic and soil conditions under which the almond thrives are much more limited than for most of the common deciduous fruits; the area of production in America is limited largely to California; the industry is comparatively new, and in general, there is not the great varietal variation in season, appearance, texture, flavor and behavior that is found in the apple, peach, pear and similar fruits. The comparatively rapid deterioration of fleshy fruits after ripening makes a succession of varieties desirable to extend the period of consumption. With almonds, the season of all varieties extends from one harvest to the next, if properly handled. Growers are, therefore, recommended to plant only standard, marketable varieties as far as possible.

Early ripening varieties must be chosen. The crop must be in the hands of the trade early, for the bulk of it is used in the holiday trade. This is especially true with unshelled almonds. Early almonds only can be harvested and sold before the bulk of the European shipments arrive.

The actual time of ripening of the different varieties is variable from season to season, and in different sections or even different orchards in the same season. Generally, harvesting commences early in August and closes about the middle of October. The approximate order of ripening of the better known varieties is shown intable IX.

Many new varieties have been originated in California but most of them have fallen into disfavor in a short time. In fact, it is impossible to locate even single trees of some varieties which were formerly wellknown. From time to time, however, worthy varieties have been introduced and have succeeded in making a permanent place for themselves through their ability to fill a demand that before had been but partially or poorly supplied.

In view of the changing market situation for California almonds, due to the rapidly increasing acreage and the very limited demand for unshelled almonds, it is safe to predict that the only new varieties which will be of value in the future will be those that are primarily of superior quality for shelling purposes. Yield must take second place.

Well known varieties are not only in heavier demand in the principal markets, but they invariably bring much better prices than the newer varieties. In some years, when the domestic crop of a given variety is light and the demand good, it is possible to unload poorer or less known varieties at fairly good prices. More often, however, they are a drag on the market.

Owing to the increasing consumption of shelled almonds and the probability of a still greater increase in the future, growers should arrange future plantings with a view to supplying the best shelling varieties. At the present time, the best shelling varieties are not ordinarily the heaviest producers. With a limited production they may not even bring as large returns as the poorer but heavier yielding varieties. As the production increases, which it is doing very rapidly, the relative value of the best shelling varieties will increase in proportion and they may be sold at good prices when it will be impossible to move a heavy tonnage of a poor variety at a profitable price.

Although the future almond markets will no doubt use shelled almonds very largely, there will always be a limited demand for unshelled almonds for use in the holiday trade and for home table use. Unshelled almonds to be acceptable for such purposes must be large, attractive nuts with light-colored, clean-looking shells, soft enough to be broken with the hands. The kernels must be well filled and free from gum. The I.X.L. is the most popular and highest-priced nut for this purpose. The Ne Plus Ultra ranks next because of its attractive outside appearance and shape; one of the principal objections to it being its tendency to have gummy kernels. The Drake is another variety in demand for this purpose. It is moderately large, plump and well filled with a good quality kernel, and while not as attractive as the I.X.L. or Ne Plus Ultra, it is popular with the medium-priced trade. A certain class of trade prefers the Nonpareil for such use, and it appears to be growing in popularity because of the attractive kernel and the ease with which shelling by hand is accomplished.

The confectioners, on the other hand, care nothing for shell. They want a medium or large sized kernel, uniform in shape, and plump; one that can be coated smoothly or evenly with candy. For blanching and salting purposes, the kernels must be large and smooth. The best California variety for this purpose is the Nonpareil. It is also the best nut for table use when sold shelled. As a rule, the papershell varieties are the best for shelling because of the large percentage of unbroken kernels which may be obtained. The broken kernels and those obtained from cheaper and less desirable varieties are used largely by the bakers and almond-paste manufacturers.

The planting of large blocks of orchards to single varieties is not a wise practice. Planting of several varieties will assist greatly in lengthening the harvest season, and thus enable one to handle large crops with fewer men and less equipment. For example, the four best varieties—the Nonpareil, I.X.L., Ne Plus Ultra and Drake—ripen in the order named; the Nonpareil ripening about two weeks before the I.X.L., the Ne Plus Ultra about a week after the I.X.L., and the Drake about two weeks after the Ne Plus Ultra. Where there is danger of failure of varieties to set fruit due to frost or improper pollination or unfavorable weather conditions during, or soon after, blooming, the grower is more likely to get a crop from some variety if several are planted to secure a succession of bloom in the spring.

The principal reason for interplanting varieties is to secure adequate cross-pollination. For this purpose the Ne Plus Ultra and Drake are probably the best to use as pollenizers.

Other combinations, as indicated onpage 6, may be made that will be satisfactory, though care must be exercised to secure varieties that blossom near enough together to be effective.Figure 26shows the effective blossoming period for fifteen varieties.

Adaptation of Varieties.—The best marketable nuts are, as has been suggested, few in number, and most of these do well in all of the principal almond districts of California. Where the climatic and soil condition are equally favorable there is no great variation in their behavior, but owing to such differences it has been found that certain varieties are better adapted to some districts than others.

The Nonpareil, the best variety known at the present time for California conditions, bears more nearly uniform crops from year to year and shows a wider range of adaptation than any of the other good commercial varieties. It has proved itself to be satisfactory in every almond district in the state. The Drake closely approaches the Nonpareil in this respect. The I.X.L. and Ne Plus Ultra are themost variable in their behavior. The blossoms of the two varieties seem to be more tender and hence more liable to injury under unfavorable conditions; gumming is more prevalent near the coast, and during harvest the slower ripening and opening of the hulls in the more moist atmosphere in many of the coast valleys causes excessive darkening and sometimes molding of the shell. The Ne Plus Ultra does its best on comparatively high, well-drained soils, adjacent to the larger streams in the Sacramento Valley, such as the lands along the Sacramento River, Putah Creek, Cache Creek, etc., though it also grows and produces well in the Banning district and in many of the foothill sections where conditions are favorable. The I.X.L. does best on the foothills surrounding the Sacramento Valley, notable on the west side. In the Banning district the Ne Plus Ultra seems to be a better producer than the I.X.L. Varieties which ripen later than the Drake should be avoided in the Banning district because of the liability to damage from the frequent October rains.

There are a number of different varieties, such as the Eureka and Jordan, which give promise of filling a limited place in the markets but which have not yet been thoroughly tested throughout the state. The Eureka is popular with confectioners because of the similarity in shape to the Jordan. In limited quantities the demand is good. It is still a question as to whether it would hold up in price if grown in very large quantities. The Jordan nut is of excellent quality but in California the trees are variable in vigor. In some cases the trees make unusually large, vigorous growth while in others they are small and apparently stunted. The cause of this has never been adequately determined. In general, the Jordans do not bear sufficiently heavy crops to make them pay at the prevailing low prices. The chief reasons for the low prices are the extreme hardness of the shell and the absence of satisfactory methods of shelling. The invention of a satisfactory machine for this purpose would probably make it pay to plant Jordans in much larger quantities.

Fig. 26.—Period of Effective Blossoming of Almonds—University Farm—1917.

Other varieties, such as the Texas, have been sufficiently tested to show them to be well adapted to most districts, but they are not to be recommended because of the difficulty experienced in marketing them at a profit in large quantities. The Texas has been planted extensively in California without sufficient justification. It was planted because of its value as a pollenizer, its precocious and prolific bearing, and its upright habit of growth. In small quantities it was sold in less exacting markets as a Drake, but in larger quantities there has been a good deal of objection to it on the part of the trade. As the bearing trees become older and bear heavier crops, the nuts tend to become smaller and the shells harder, which increases the difficulty of selling. From the standpoint of the grower as well as the market, the lateness in ripening is very objectionable. The California Almond Growers’ Exchange is finding it harder each year to satisfactorily market the rapidly increasing tonnage of this variety. It should, therefore, be avoided in new plantings.

Records of fourteen varieties of almonds grown in the same orchard under similar conditions of soil and culture have been kept at the University Farm at Davis, for the years 1913 to 1916, inclusive. These trees are all of the same age, except the Texas, Peerless and Harriott, which are one year younger than the others. These figures show that there is a wide variation within varieties from year to year, not only as regards size, but proportion of shell to whole nut, and in the proportion of double kernels.

Table Xshows the variation in size from year to year, as indicated by the number of nuts per pound. Five-pound samples of each variety were used to determine the average size:

The value of an almond for shelling depends not alone on its relative ease of cracking, but also upon the percentage of kernel to the whole nut as shown intable XI:

Double kernels are particularly undesirable in nuts for shelling because of the irregular shape of the halves, which renders them unfit for confectionery or bakery purposes where whole kernels are used.Table XIIshows the percentage of double kernels by number:

Almonds are classified according to hardness of shell, into four classes:

Papershell.—Those almonds having a thin, papery shell which may easily be broken between the fingers of one hand.

Softshell.—Those which have a more or less spongy or thin shell which may be broken between the fingers of two hands.

Fig. 27.—Almond varieties.LANGUEDOC. TEXAS. DRAKE.NONPAREIL. I.X.L. NE PLUS ULTRA.TARRAGONA. JORDAN. PEERLESS.

Fig. 27.—Almond varieties.

LANGUEDOC. TEXAS. DRAKE.

NONPAREIL. I.X.L. NE PLUS ULTRA.

TARRAGONA. JORDAN. PEERLESS.

Standardshell.—Those requiring very strong pressure of the hand or the use of a nut-cracker to break. These may have a spongy or smooth outer shell.

Hardshell.—Those which cannot be broken by hand but require a sharp blow with a hammer or strong pressure with a nut cracker to crack them.

The papershell varieties are excellent for shelling as they contain a large percentage of kernels which may easily be obtained whole. The principal objections are that birds are particularly fond of them since they can crack them easily, and the shells are often poorly sealed.The latter fact makes it difficult to prevent worm infestation and to prevent the penetration of sulphur fumes to the kernel during the bleaching process. As a result practically none of the papershells are bleached but are sold for shelling purposes.

The softshells are generally more attractive for table use because the shells are more perfect and, in commercial varieties, are brighter in color and more attractive. The shells are usually well sealed and can be bleached to give additional brightness with less danger of the fumes penetrating to the kernel than the papershells.

Fig. 28.—Almond varieties.HARRIOTT. EUREKA. LEWELLING.KING. CALIFORNIA. PRINCESS.STUART. LA PRIMA. BATHAM.

Fig. 28.—Almond varieties.

HARRIOTT. EUREKA. LEWELLING.

KING. CALIFORNIA. PRINCESS.

STUART. LA PRIMA. BATHAM.

The standardshells have the greatest range in character, thickness and hardness of shell. For table use they are sometimes too hard for high-class trade. The percentage of kernel is too low to make them very attractive to the retail trade. Of this class of almond the Drake is probably the best of the California varieties. Almond varieties of all these classes are shown infigures 27 and 28. These illustrations show most of the varieties grown to any extent in California and others that have attracted much interest and inquiry, together with the European Tarragona.

FOOTNOTES[1]Tufts, W. P., unpublished data from experiments conducted in the University Farm orchard, at Davis, California.[2]Colby, Geo. E., Ann. Rept. Cal. Agri. Exp. Sta., 1895-1896 and 1896-1897.[3]As this bulletin goes to press doubt is raised as to whether some of these trees may not be on almond stock, but this in no material way affects the discussion.[4]Just what conditions will exist after the close of the present war cannot be forecast with any degree of accuracy. One thing is certain, the increasing popularity of shelled almonds makes it essential that the American markets become familiar with the California shelled product, and that this trade be extended as quickly as possible.[5]Cir. 121, Univ. Calif. Agri. Exp. Station, October, 1914.[6]The fumigation of Stored Grain, Dried Fruits, and Other Products, E. R. DeOng, Cal. Agr. Exp. Sta., Dec., 1917.

FOOTNOTES

[1]Tufts, W. P., unpublished data from experiments conducted in the University Farm orchard, at Davis, California.

[2]Colby, Geo. E., Ann. Rept. Cal. Agri. Exp. Sta., 1895-1896 and 1896-1897.

[3]As this bulletin goes to press doubt is raised as to whether some of these trees may not be on almond stock, but this in no material way affects the discussion.

[4]Just what conditions will exist after the close of the present war cannot be forecast with any degree of accuracy. One thing is certain, the increasing popularity of shelled almonds makes it essential that the American markets become familiar with the California shelled product, and that this trade be extended as quickly as possible.

[5]Cir. 121, Univ. Calif. Agri. Exp. Station, October, 1914.

[6]The fumigation of Stored Grain, Dried Fruits, and Other Products, E. R. DeOng, Cal. Agr. Exp. Sta., Dec., 1917.

BIBLIOGRAPHYTreat, W.1890. Almond Culture. Report of California Board of Horticulture, 1900, pp. 72-78.Fuller, A. S.1896. The Nut Culturist, pp. 12-43. Orange Judd Co., New York.Corsa, W. P.1896. Nut Culture in the United States, Embracing Native and Introduced Species. U. S. D. A., Division of Pomology, pp. 19-28.Colby, Geo. E.1898. Analysis of California Almonds. University of California Agr. Exp. Sta. Report 1895-1896; 1896-1897, pp. 145-151.Fairchild, David G.1902. Spanish Almonds and Their Introduction into America. Bulletin 26, Bureau of Plant Industry, U. S. D. A., pp. 7-14 and 8 plates.Dargitz, J. P.1909. The Almond Commercially Considered. Proc. 36th Cal. State Fruit Growers’ Convention, pp. 64-71.Wickson, E. J.1914. California Fruits and How to Grow Them. 7th edition., pp. 424-430.Bailey, L. H., andWickson, E. J.1914. Almond, Standard Cyclopedia of Horticulture, vol. I, pp. 249-251.Hunt, Thos. F., and Staff.1914. Some Things the Prospective Settler Should Know. Circular 121, Cal. Agr. Exp. Station, pp. 3, 8, 41-42.Taylor, R. H.1915. Present Status of the Nut Industry in California. Proceedings of the Society for Horticultural Science, 1915, pp. 31-39.1915. A Symposium of California Pomology: The Almond. Proceedings American Pomological Society, 1915, pp. 121-126.Pierce, Geo. W.1915. The Status of the Almond Industry of the Pacific Coast. Proceedings American Pomological Society, 1915, pp. 75-82.Steubenrauch, A. V., andTaylor, R. H.1915. Some Lessons from the California Nut Industry. Proceedings 14th Ann. Conv. National Nut Growers’ Association, 1915, pp. 90-93.

BIBLIOGRAPHY

Treat, W.

1890. Almond Culture. Report of California Board of Horticulture, 1900, pp. 72-78.

Fuller, A. S.

1896. The Nut Culturist, pp. 12-43. Orange Judd Co., New York.

Corsa, W. P.

1896. Nut Culture in the United States, Embracing Native and Introduced Species. U. S. D. A., Division of Pomology, pp. 19-28.

Colby, Geo. E.

1898. Analysis of California Almonds. University of California Agr. Exp. Sta. Report 1895-1896; 1896-1897, pp. 145-151.

Fairchild, David G.

1902. Spanish Almonds and Their Introduction into America. Bulletin 26, Bureau of Plant Industry, U. S. D. A., pp. 7-14 and 8 plates.

Dargitz, J. P.

1909. The Almond Commercially Considered. Proc. 36th Cal. State Fruit Growers’ Convention, pp. 64-71.

Wickson, E. J.

1914. California Fruits and How to Grow Them. 7th edition., pp. 424-430.

Bailey, L. H., andWickson, E. J.

1914. Almond, Standard Cyclopedia of Horticulture, vol. I, pp. 249-251.

Hunt, Thos. F., and Staff.

1914. Some Things the Prospective Settler Should Know. Circular 121, Cal. Agr. Exp. Station, pp. 3, 8, 41-42.

Taylor, R. H.

1915. Present Status of the Nut Industry in California. Proceedings of the Society for Horticultural Science, 1915, pp. 31-39.

1915. A Symposium of California Pomology: The Almond. Proceedings American Pomological Society, 1915, pp. 121-126.

Pierce, Geo. W.

1915. The Status of the Almond Industry of the Pacific Coast. Proceedings American Pomological Society, 1915, pp. 75-82.

Steubenrauch, A. V., andTaylor, R. H.

1915. Some Lessons from the California Nut Industry. Proceedings 14th Ann. Conv. National Nut Growers’ Association, 1915, pp. 90-93.

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