Pegmatite

“ Apatite is especially abundant in some pegmatites. In a few places, as in the Adirondacks where magnetic [Pg 106] concentration of iron ores leaves a residue containing much apatite, and in Canada and Spain where veins of apatite have been mined, this material is used as a source of phosphate fertilizer. The great bulk of the world's phosphate, however, is obtained from other sources—sedimentary and residual beds described below.
Phosphorus in the rocks is dissolved in one form or another by the ground-waters ”

“ Furthermore micropegmatite is not always the last consolidation product, as a eutectic should be, but may occur as well-shaped phenocysts lying in a felsitic or glassy matrix which solidified at a still later time. Micrographic structures in the minerals of igneous rocks prove only that these minerals crystallized simultaneously. ”

“ In some rocks the whole ground mass consists of such spherulitic growths of fibrous micropegmatite (see Quartz-Porphyry) ; in their centres there is often a quartz or felspar crystal; the outer boundaries of the spherulites are not usually circular but irregular owing to the interlocking of adjacent spherulites at their margins (“granophyric structure”) . Micrographic structures may occur in other minerals, e.g. quartz and garnet, cordierite, epidote or hornblende, augite and felspar, but are less common, and the name micropegmatite is usually reserved for aggregates of quartz and felspar. ”

“ Hornblende when primary is often brown, and may surround augite or be perthitically intergrown with it; original green hornblende probably occurs also, though it is more frequently secondary. Dark-brown biotite, although by no means an important constituent of these rocks, occurs in many of them. Quartz is rare, but is occasionally seen intergrown with felspar as micropegmatite. Among the accessory minerals may be mentioned apatite, magnetite, ilmenite, picotite and garnet. ”

“ The pecan scab is the most typical fungus parasite of the pecan. It attacks the leaves, fruit, etc. It attacks the vessels or veins of the leaves and frequently enters by means of aphis punctures which break the skin so that there is no doubt but that this particular disease is favored by an aphis. We have investigated this disease quite carefully and carried on a series of spraying experiments for some three years and there is no doubt about our ability to control it. It can be prevented by spraying with Bordeaux mixture. You never can tell how many sprayings will be required. ”

“ Bordeaux mixture is the thing to be used on all occasions. The pecan resists copper poisoning almost as well as the grape and can be sprayed with safety.
If a pecan tree has crown gall don't plant it. All nursery trees should be rejected in planting if they show signs of this disease. The pecan has fungus root-rot and various wood rot fungi besides the leaf diseases. ”

“ The diseases that affect the pecan, especially those caused by fungi, are rapidly spread throughout the trees in an orchard in the early spring. During this season of frequent rains, the spores of the disease fungi germinate and invade the young tender tissues of the shoots, leaves and nuts. Under conditions of prolonged damp weather, when the humidity remains high, the disease organisms reproduce at a rapid rate and cause severe shedding of leaves and nuts. ”

“ Rosette is a nutritional deficiency disease caused by certain soil conditions which make zinc unavailable to the pecan tree. All pecan trees require zinc for growth.
Trees showing the first symptom of zinc deficiency have yellowed tops. The individual leaflets when examined are yellowish and mottled. The next season the foliage may be yellowish and the leaflets narrowed and crinkled. More severely affected trees produce foliage which is a yellowish to reddish-brown overall color, and the leaflets are very narrow with reddish-brown spots and may be perforated. ”

“ For all fungous diseases of the pecan which may be controlled by spraying no substance will give better results than Bordeaux mixture, and directions for preparing it are given at the end of this chapter. Paris green, at the rate of four ounces to each fifty gallons of liquid, may be added to the mixture for the destruction of biting insects. For effectual work in spraying large trees, a platform should be erected on the wagon-bed to make it possible to reach the tops with the spray. ”

“ A physiological disorder in a pecan tree may result from infertile soil, excessive moisture, or the absence or degree of available nutritional mineral elements to the growing tree. These various environmental factors have special adverse effects, manifested by specific symptoms caused by insufficient levels of a given nutritional mineral element or elements, which are easily corrected by supplying the tree the necessary mineral elements either through soil application or foliage sprays. ”

“ Pecans are attacked by more than 20 species of insects that cause damage to leaves, nuts, twigs, buds, branches and even the bark. The development of commercial pecan acreages has provided ideal conditions for the increase in severity of both disease and insect damage because of the abundant food supply in a concentrated planting of pecans. In its natural habitat the pecan is less subject to the devastations of diseases and insects. ”

“ When infection is severe, the entire nut surface is black in appearance, development is arrested and the nuts drop prematurely.
Figure 1. Scab lesions on leaves and nuts of Delmas variety. Note concave lesions and overall scabby appearance of severely infected nuts.
Pecan varieties vary in their susceptibility to scab disease. Among the highly susceptible varieties are: Burkett, Delmas, Schley, Moore, Halbert and most western varieties. Moneymaker, Success and Curtis are moderately resistant. Mahan, Stuart and Desirable varieties are highly resistant to the scab fungus. ”

“ New orchards should not be planted in soil having a history of cotton root rot disease.
Pecan Insects and Their Control PECAN NUT CASEBEARER
The pecan nut casebearer, Acrobasis caryae Grote, is the major pest of pecans in Texas. Early in the spring, the overwintered generation feeds first in the buds and then in the developing shoots, causing them to wilt and die. Succeeding generations feed on the nuts during the late spring and summer, Figure 9. Severe infestations may destroy the entire crop of pecans. ”

“ Control.—The control of pecan scab disease depends primarily on the protection of tender leaf, nut and shoot surfaces with proper application of an effective fungicide. A protective film of fungicide chemical prevents scab fungus infections by killing the spores immediately after their germination, thereby preventing invasion of susceptible tissues. Unfortunately, once the fungus has invaded the tissues it becomes protected from chemical attack and produces spores in great abundance. ”

“ The pectins more nearly approach to the composition, properties, and functions of the celluloses than do any of the other groups of organic compounds. They have been extensively studied in connection with the parasitism of certain fungous diseases which cause the soft rots of fruits and vegetables. These parasites usually penetrate the tissues of the host plant by dissolving out the middle lamella material, which may sometimes serve as food material for the fungus; but more often the parasite secures its food supply from the protoplasm of the cell contents. ”

“ Then we have the more permanently dangerous disease, pecan rosette, which has taken about half of the pecans in some sections of the South, especially in south Georgia and in Florida. That disease is being experimented upon in the most extensive way of any of our projects. There is only one word to say about pecan rosette, and that is—humus—the disease is cured by the application of humus. ”

“ Usually, these insects are not present in sufficient numbers to cause serious injury until mid or late summer. Infestations earlier in the season rarely assume damaging proportions. As is the case with mites, aphid populations may increase, following the application of certain insecticides applied for the control of the pecan nut casebearer or following treatment with bordeaux mixture for pecan scab disease control. ”

“ Some of the common pecan storage troubles are staleness, rancidity, color changes, molding, and insect injury. Molding occurs only when the product is stored in a moist atmosphere at ordinary temperatures. Insect infestation usually results when the shelled kernels are held in unsealed containers under ordinary storage conditions. Rancidity develops during the summer months when the product is stored by common, methods at ordinary temperatures. ”

“ Rancidity is probably the most common of pecan storage troubles; it has been considered the most difficult to control. Rancidity is usually preceded by general loss of flavor followed by staleness of kernels. Color gradually becomes darker as the typical rancid condition develops. ”

“ The many destructive insects and diseases must be controlled for successful pecan production. The pecan grower must also understand the nature and habits of the various disease and insect pests that threaten his crop and use certain cultural practices which help to reduce damage from diseases and insects. ”

“ The larvae which hatch from these eggs develop slowly, and do not attain a length of more than one-sixteenth inch during that season. They construct little winding cases in which they live. Their feeding produces irregular blotches on the leaf surface, Figure 16. Before the leaves drop in the fall, the larvae migrate to the buds, and construct their overwintering hibernacula. Only one generation is completed each year.
Control.—Control of this insect is accomplished by spraying for the pecan nut casebearer. See spray schedule, page 4. ”

“ Das Berg- und auch das wilde Peganon ist schärfer als das gebaute und das der Gärten und zur Speise nicht geeignet. Vom Gartenpeganon ist das aber zum Essen besser, welches bei den Feigebäumen wächst. Beide sind brennend, erwärmend, Geschwüre machend, harntreibend, die Menstruation befördernd, gegessen sowohl wie getrunken stellen sie den Durchfall. Sie sind ein Gegenmittel gegen Gifte, wenn vom Samen ein Essignäpfchen voll in Wein getrunken wird. Die Blätter für sich allein und auch mit Wallnüssen und trockenen Feigen, vorher genommen, machen tödlichen Gifte unwirksam. ”

“ Blepharitis and conjunctivitis may be due to Pediculus capitis.
The means of infection are often very remarkable. Transmission from one individual to another certainly often occurs, but infection may take place in railway carriages and in other ways. A case under the observation of a colleague in Frankfort is a most remarkable one: he diagnosed pediculosis as the cause of a head eczema occurring among the children of one of the best families there. The infection took place through dolls adorned with human hair, in which the presence of nits could be demonstrated. ”

“ The same lusus naturæ is met with, I think more frequently, in rock-crystal and in the dark fluor-spars.
The last apparent animal organism which I shall notice, as having more than once occurred to me as a possible explanation of the patterns disclosed in certain sections of agate-pebbles, is that of some creature’s “ovary.” The eggs of the whelk, and those of the cuttle-fish, are deposited in clusters, like some of the “grapes” on sea-weed. I have found, in some of the Isle of Wight pebbles, a conformation closely resembling this, but on a much smaller scale. ”

“ We are still in our infancy and have many problems and the problems multiply as days and years go by. Fifteen years ago we would have said there were no insect pests nor any diseases of the pecan. They have certainly made themselves known in the last few years. We have a good many insect pests and we have some fungus. ”

“ Pecan Scab (Fusicladium effusum) : This disease attacks the fruit, leaves and twigs. The husks of the diseased nuts become covered with dark spots or specks. They become hardened and crack open in places. As a result of the attack, growth is stopped, the fruit does not fill out and mature, but drops prematurely or, in some cases, remains attached to the trees long after the leaves have fallen. ”

“ This aphid is usually controlled with nicotine sulfate (40 percent nicotine) , 3/8 pint plus summer oil emulsion, 2 quarts per 100 gallons of spray. Parathion and benzene hexachloride have given good results in experimental work but are not yet generally recommended.
~Pecan phylloxera.~ The pecan phylloxera [16] is related to aphids. It attacks principally the vegetative parts of the tree such as the leaves, petioles, and shoots on which galls (Fig. 6) are produced. Pecans, hickories, and other species of nuts are subject to infestation. ”

“ Trees affected by rosette for several seasons have many dead shoots and small branches from the dying-back of each season’s growth, Figure 4. Such trees are greatly stunted, of poor vigor and produce few, if any, nuts.
Control.—Rosette is controlled readily by applying zinc sulfate to the tree either as a foliage spray or in the dry form as a soil application. Where a disease and insect spray control program is being carried out, zinc sulfate may be added to the spray mixture.
Foliage spray. Two pounds zinc sulfate (36 percent) per 100 gallons of water. ”

“ Pectic acid, though it rarely exists ready-formed in the plant, can readily be obtained from it by the action of weak alkalis. It is best procured by boiling the pulp of turnips with a 10 per cent. solution of sodium carbonate for about half an hour. If an acid be added to the filtered liquid, pectic acid is precipitated as a transparent colourless jelly, which {29} dries up to a transparent horny mass. By the prolonged action of alkalis or acids, pectic acid is converted into metapectic acid (C8H14O9) , which may be obtained as a syrupy, strongly acid liquid. ”