Information About Pear

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What are the characteristics, features, uses of pear? Information about the cultivation of pear tree and pear fruit.

pear

PEAR, a tree (Pyrus communis) of the natural order Rosaceae. It is probably a native of western Asia and adjacent Europe, whence it has been introduced by man into all temperate climates of the civilized world. The chief producing countries are France and the United States, and in the latter the principal regions are California, Washington, Oregon, New York, Michigan, Illinois, Pennsylvania, and New Jersey. Among the fruits of the United States the pear ranks fifth in commercial importance. It is distinctly a cool climate tree, but except for certain inferior Russian varieties does not thrive on the cold Western plains. Some of its hybrids with the Chinese sand pear {P. sinensis) do well in the South, but their inferior quality is against them. The Kieffer, Orient, Garber and Smith varieties are most often planted; the first not only in the South, but very generally throughout the Eastern States. This is a chance hybrid between the original species, which was grown for ornament by Kieffer, a Philadelphia nurseryman, and was introduced as an acquisition. It is famous for poor quality, but is extensively used as a substitute for the Bartlett, especially in canning. The Bartlett, a European variety known as Bonchrétien, is the most widely cultivated pear in the United States, being popular in all the pear-growing regions. The most noted variety in point of quality is the Seckel, an American sort, which though of small size is considered the acme of the thousands of varieties cultivated throughout the world. Of the winter varieties Beurre d’Anjou, Beurre Bosc, Doyenné du Comice and Winter Nelis are the best-known commercial pears grown in the United States and practically all of these are to be found in the Pacific Coast states.

The pear is generally propagated by budding the desired varieties into seedling stocks. These seedlings were formerly imported from France, but in recent years domestic stock is utilized almost exclusively. Although seed of almost any variety is suitable for seedling stock, Bartlett seed is generally used because of its availability as core waste from commercial pear canneries. For a number of years the Japanese stock (P. serótina) was used extensively as understocks, but it has since proved to be unsatisfactory. An abnormal condition of the pear fruits known as “black end” is associated with the Japanese -roots. Trees propagated on either French, domestic, or Japanese seedlings develop into what are called standard trees, and are planted 20 to 25 feet apart in the orchard. Dwarf trees are produced by grafting the pear upon quince stock, and should not be planted closer than 12 feet, and 15 feet apart is even better. The usual methods of planting are in squares, in rectangles, in “quincunx” form, and in hexagons. The first two are popular in the East, the last on the Pacific Coast. The last is generally best from the standpoint of economical utilization of ground.

The pear will grow upon almost any soil, but thrives best on well-drained loams, except the Chinese hybrids which do best upon lighter soils. Air drainage is as important as water drainage ; therefore, the orchard should be on high ground. The field should be deeply plowed and thoroughly harrowed before the trees are set, and throughout the season the land should be kept loose, open and free from weeds by frequent cultivation. About midsummer a cover crop should be planted to conserve the plant food that might be wasted by leaching during the winter. If leguminous crops are employed for this purpose, they should obviate the necessity of fertilizing heavily with nitrogenous fertilizers. Potash, phosphoric acid, and magnesium may be needed in certain orchard locations where these elements are found to be lacking.

After the trees are set the tops should be pretty severely pruned, only two or three buds being left upon from three to five well-placed twigs, preferably 30 inches from the ground. The ideal form for training the pear resembles that of a vase, because when attacked by pear blight or fire blight the tree can then often be saved, whereas if trained with only one trunk it usually cannot. Each main limb should be made to divide and redivide, thus forming a spreading tree with a somewhat hollow centre. Though the work during the first five years of the orchard’s life may seem excessive its value will be appreciated in after years. Dwarf pears should also be trained in this form ; but since they must be kept dwarfed (below 12 feet) and since they have a tendency to develop into standards, especially if the scion takes root above the quince stock, they must be severely cut back late each winter. Many growers advocate removing fully two-thirds of the annual growth of the previous season. Care must be taken in pruning all pear-trees to save the gnarly twigs, which are generally of irregular thickness and direction. These are ‘ the fruit-bearing spurs. They do not appear upon young trees.

The pear is more noted for self-sterility than most other perfect flowered fruits; the pollen of certain varieties is impotent upon the pistils of the same variety. Failure to set fruit may also result from a variety of causes, such as cold or rainy weather at blossoming time, and difference in time of opening of the flowers of adjacent varieties. To obviate self-sterility, two or more varieties should be chosen which blossom simultaneously, and these should be planted in adjacent rows, not more than three rows of a kind together—preferably two.

Bartlett may be used as a satisfactory pollinizer for most of the other important varieties except Seckel. The Beurre d’Anjou, which is strongly self-sterile, may be pollinated by the Bartlett, Beurre Éosc, Winter Nelis, Easter Beurre, Doyenne du Cornice, and Flemish Beauty, all of which are satisfactorily cross-pollinated by Beurre Bosc, Gorham, Beurre d’Anjou, Duchess d’Angouleme, Flemish Beauty; the Seckel by Duchess d’Angouleme but not Bartlett; and the Gorham by Bartlett and Duchess d’Angouleme. The Beurre Bosc is adequately cross-pollinated by Bartlett, Beurre d’Anjou, and Flemish Beauty.

The pear flower is entomophilous in character, insects being required for cross-pollination. Bees are the best pollen carriers, one hive to an acre of orchard generally being sufficient. Wild bees and other insects also aid in cross-pollination, but honeybees appear to be the chief distributor of pear pollen, and the closer bees are placed to pear trees, the more effective they are as pollen distributors. Under certain conditions, the average pear variety has a tendency to set fruit parthenocarpically, or without fertilization and consequent seed development. In some sections, Bartlett will parthenocarpically set a good crop of seedless pears, but these fruits tend to be shaped differently from pollinated and seeded pears.

Pears should be harvested when they will readily separate from the twigs without breaking the fruit stalks. If allowed to hang upon the tree until fully ripe they usually lose flavor and become more gritty. The elapsed interval of time from full bloom to first maturity is relatively constant from season to season. Thus, the number of days from bloom is a helpful index in determining the desirable harvest time for pears. It has been determined that in order to attain adequate maturity for good keeping, marketing, and eating quality, pear varieties should be harvested a given number of days after full bloom, as follows: Bartlett, 110 to 115; Beurre Bosc, 130 to 135; and Beurre d’Anjou, 145 to 150 days. Perhaps the most widely used method of determining harvest maturity of pears is the pressure test. Firmness of flesh is measured by a pressure tester that records the amount of pressure in pounds required to force a rounded plunger 5/16-inch in diameter into the pared flesh of the pear to a depth of 5/16-inch. As the harvest season progresses, the pressure in pounds becomes less. The optimum pressures recommended for harvesting varieties of pears are as follows: Bartlett, 20; Beurre Bosc, 14; Beurre d’Anjou, 13; Doyenne du Cornice, 11.5; Winter Nelis, 14 pounds.

Some varieties of pears tend to fall to the ground before they reach harvest maturity. Since 1940, many commercial fruit growers have profitably sprayed pear trees just before harvest time in order to prevent this fruit drop. Ingredients used in these sprays are known as plant growth regulators or hormones; namely, naphthalene acetic acid and 2,4-dichlorophenoxyacetic acid. Control of fruit drop has been effective with either substance at a spray concentration of 21/2 parts of the chemical in one million parts of water. In addition to the conventional method of spraying, these chemical hormones are sometimes applied by means of airplanes, and since 1945 many thousands of acres of both apple and pear trees have been treated with hormones by this method. When gathered they are usually hard and imperfectly colored, but if stored in a cold room, preferably in boxes, they will acquire both good color and flavor, besides obviating grittiness and breakdown at the core to a great extent. Freely circulating air, especially if warm, tends to shrivel the fruit, make it decay and impair the flavor. Winter pears may be left upon the trees until danger of frost is feared; then they should be carefully harvested and stored at 32°F., being removed for ripening to warmer quarters as needed.

Several of the diseases which attack the pear have been treated under the article Apple. The two most dreaded maladies are pear blight and a fungus leaf blight. The former is attributed to a species of bacterium which may gain entrance to the tissues at any “naked” point such as a wound, tips of growing twigs, or, especially, through the nectaries and pistils of the flowers, to which it is conveyed by insects. The disease manifests itself by the blackening of the foliage which hangs on the tree. As the organism works its way down the limbs toward the trunk, it discolors the young tissues upon which it subsists just beneath the bark. In early spring there may be a somewhat saccharine exudation from affected parts of the trunk and limbs. Insects carry infection from these places. Hence the advisability of examining the trees and removing diseased parts in late winter. Whenever the operation is performed the affected branch should be removed several inches below the point of discoloration. Many orchardists recommend sterilizing the tools after each operation, using a solution of bichloride of mercury. The disease is believed to be more prevalent when growth is vigorous. Some varieties, such as Duchess d’Angouleme, Waite, and Kieffer, are considered fairly resistant. There is now a concerted effort made to breed pear trees for greater blight resistance, and for higher dessert quality in the fruit.

Pear leaf blight (Fabraea maculata) is distinct from the previous disorder, being of fungus origin. It appears upon the twigs as black spots; upon the leaves as more or less coalescent reddish brown spots; upon the fruit as upon the leaf, the underlying tissues being hard and corklike, badly attacked specimens often becoming lopsided and cracked. The trees are frequently defoliated from the falling of the leaves. Bordeaux mixture is considered a specific; many varieties formerly failures now being grown successfully where sprayed. Applications should be given at intervals of two weeks from the time the buds commence to swell until early summer, or, in wet seasons, later and more frequently. Leaf burn resulting from the use of Bordeaux mixture is sometimes a serious limitation.

Among the numerous insects that feed upon the pear the following are probably best known and most easily controlled : Fall webworm, Cecropia moth, eye-spotted bud moth, white marked tussock moth, red humped appletree caterpillar, codling moth, all of which may be combated by spraying. The San José scale and the oystershell bark louse, like several of the above, attack pear and apple. indiscriminately. Several borers are often troublesome, for instance, the sinuate pear borer (Agrilus sinuatus), a European species which tunnels irregularly in the trunk ; and the borers mentioned under Apple. The larvae of the pear blight beetle (Xyleborus pyri) burrow in and cause the twigs to wilt. When discovered the withered twigs should be removed and burned. The pear slug (Eriocompoides limacina) is the larva of a sawfly probably introduced from Europe. The slugs, which feed upon the leaves, are covered with a slimy secretion to which powdered lime will adhere ; hence its use, and also that of road dust, as a remedy.

Probably the most troublesome pear pest is the pear tree psylla (Psylla pyricola), a flea louse which seems to be confined to this tree. It is most abundant from Michigan to Virginia and northward, into which region it was probably introduced from Europe about 1832. The orange colored eggs are laid upon the leaves upon which the red-eyed yellow larvae feed by sucking the juices. Four or more generations appear before frost, at the approach of which the adults hide for hibernation in crevices of the bark. Among the remedies recommended, scraping the trunks, spraying in winter with crude kerosene» and with kerosene emulsion when the buds expand, with a second application just before blossoming, are probably the most favored. The psylla has numerous natural enemies ; especially the larvae of lady-bird beetles and of lacewing flies. Several species of red spiders or mites often cause much injury to pear leaves. They are most numerous in orchards in hot, dry localities. Prompt and thorough spraying is very important.

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