Florida Fruits and how Raise Them

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J. P. Morton, 1886 - 343 páginas
 

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Página 107 - A microscopic examination of the fruit-rind reveals no forms of fungus, but shows the oil-cells to be more or less completely emptied of their contents, and the outer layers, the epithelial cells, clogged with brownish resin, or entirely broken up and divided by fissures, which permit evaporation of the fluids from the underlying cells. The rind of rusted fruit, therefore, shrinks and toughens, and loses by evaporation or oxidation the greater part of its essential oil.
Página 112 - That they do not feed upon the chlorophyl is shown by the color of their intestinal contents, which has no tinge of green, but a clear yellow, unmistakably indicating the source from which it came. Wandering Habits. — While engaged in feeding, the mites remain quiescent for a length of time varying from a few minutes to half an hour. They then move on a short distance and again become motionless. If disturbed they have a habit of erecting themselves upon the leaf, clinging to its surface only by...
Página 116 - So readily do they relinquish their hold when brought into contact with a moving body, that the point of a needle swept across the surface of an infested leaf will usually be found to have several mites adhering to it. The same agencies which assist in the spread of scale-insects undoubtedly serve to scatter the mites. Not only do they climb readily along the web of spiders, but they may frequently be seen upon the bodies of the spiders themselves, which do not seem to be at all disturbed by the...
Página 114 - ... long endure the direct light and heat of the sun, they also avoid dark shade. At midday they are more abundant upon the under side of exposed leaves, and although they at all times show a marked preference for light, they desert those | parts of leaf or fruit upon which it falls brightest. On a leaf partially exposed to the sun, the, mites congregate near one edge in the .morning, and in the afternoon cross to the opposite side of the same surface, following the shifting shade which, by reason...
Página 110 - ... the accessible oil-cells have been emptied of their contents, or the tissues have been too much hardened by advancing maturity to be easily penetrated by their beaks. The effects of their punctures upon the cellular structure of the plant, however, continue after their departure, and upon the fruit, rust develops with a varying interval, depending possibly upon the relative humidity of the air. Usually the discoloration is very apparent after the lapse of a week, and the rind continues to harden...
Página 117 - ... the leaves and fruit of all these species of Citrus the effects of its attack are essentially the same, although the rust is most noticeable on the Sweet and Bitter Orange. Effect of Attacks upon the Foliage. — Like certain internal animal parasites which feed only upon the fat of their hosts, and do not touch its vital organs, the Mite does not destroy the vital functions of the leaf. The chlorophyl is untouched, and the plant is robbed of a portion only of its essential oil. The leaves never...
Página 111 - The length of the adult mite is ().lamm (Т(гътг inch). The young do not differ essentially in structure from the adult mites, but are thick and short, almost cordiform, and the legs are very short. The eggs, which are deposited singly or in little clusters upon the surface of the leaves, are spherical, transparent, with a yellow tinge. Their diameter is more than half that of the mite at its widest part, and they probably increase in size by the absorption of moisture after they are laid, otherwise...
Página 113 - ... and undoubtedly travel to considerable distances. Their rate of progress on a smooth surface is quite rapid, and amounts to 10 or 12 feet per hour. It is therefore not surprising to find them changing their position frequently; disappearing suddenly from one portion of a tree, and appearing as suddenly in great numbers upon another and distant part of the same tree. It is not to be understood that the mites show any concert of action in moving their colonies, or that they are in any other sense...
Página 111 - In hot weather the eggs hatch in four or five days, but in winter their development is more or less retarded by cold, although it is not entirely arrested even by frost, and the duration of the egg period seldom exceeds two weeks. The young mites are bright, translucent yellow in color. Within a week or ten days they undergo a metamorphosis or molt, during which the animal remains dormant for about forty-eight hours.
Página 197 - ... begins to repay the expense of cultivation, even if the ground is not otherwise cropped. After that period, in good years, the produce is the surest source of wealth to the farmer ; and the tree rivals the oak in longevity ; so that the common proverb here is, ' If you want to leave a lasting inheritance to your children's children, plant an olive.

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