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Treating Frozen Vines.

vines began to recuperate. The right-hand spray shows a cluster of flowers appearing upon a belated shoot. Of course, only the clusters of the largest size, as shown at the left, ripened into good fruit.

In proceeding to treat frozen vines, like those described, it must first of all be borne in mind that the injured parts are of no further use to the plants, and, as we have seen, they are very apt to weaken the plant by causing it to lose much of its moisture. The rational procedure, therefore, is to strip off all the frozen shoots soon after the disaster, so as to allow the energies of the plant to divert themselves to the production of new shoots. When the injured parts are soft and small, it is customary to remove them by pulling them off, rather than by cutting them off. In vineyards which are well pruned, the cost of stripping ought not to exceed one dollar an acre.

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What is an injurious degree of cold?*-To this oft-asked question there can be no specific answer, because so much depends upon the latitude, the time of year and the condition of the plants. Hammon gives the following " table of temperatures at which the following plants are liable to receive injury from frosts, compiled from information received from horticulturists, orchardists and gardeners throughout the entire Pacific coast.

"The temperatures given are as nearly as possible those in contact with the plant itself.

*A discussion of acclimatization, and other problems of climate and plants, may be found in "The Survival of the Unlike."

† W. H. Hammon, "Frost, How and When to Prevent Injury Thereby," 1896.

[graphic]

Fig. 63. The effects of a late freeze upon grapes, showing, respectively, fruit upon uninjured wood, and upon the secondary and tertiary growths.

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*Depends on variety.

† Injured at two degrees higher if continued 4 to 6 hours.

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18 ripe, 24 green 29

26 ripe, 29 green

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We have already seen (page 322) that at Ithaca, New York, apricots, peaches and other fruits were able to endure a temperature of 18°, even when the buds were well swollen. In respect to the variations in the effects of winter temperatures, McCluer writes from the Illinois Experiment Station as follows:

*

"Here, we ordinarily think of 14° or 15° below zero as fatal to the peach crop, and as we often have a lower temperature than that but few peaches are planted. During the winter of 1894-5 the thermometer several times ranged below 20, and once sank to 25 below zero, and yet only half the peach buds were killed, and the trees produced a good crop the season following. Last winter, with a minimum temperature of only 5° below zero, fully one-third of the peach buds were killed. I do not know just what conditions made the buds. more hardy one season than another; neither do I know why part of the buds on a tree should be more hardy than the rest. Even in the axil of the same leaf one bud may be killed and the other live.

"Other organic substances show the same differences. In a half-bushel basket of potatoes exposed to the cold in a cellar, I have often found frozen tubers scattered through the basket and the rest not frozen. In the blossom-buds of the cherry and plum one or more may often be found killed, while the rest have escaped.

*G. W. McCluer, Garden and Forest, ix. 209 (May 20, 1896).

Effects of Rain at Blooming-time.

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"When we first began to spray our peach trees to prevent the fruit from rotting, the Bordeaux mixture used was not properly prepared, and as a consequence a large part of the leaves on the sprayed trees fell off prematurely. The next spring it was found that there was a larger proportion of live buds on the trees from which the leaves had fallen than on the rest of the same variety. My explanation at the time was that the buds become less hardy in proportion as they are more developed. We know this is true in the spring. The question at once arises, at what stage in the development of a bud is it the most hardy, and how can we best control that development? This seems to me a promising field for careful study."

The effect of rain upon blossoms.-It is perfectly well known that the weather conditions in which plants are growing may profoundly affect the fecundity of the flowers. In the forcing of winter vegetables, for example, it is of the greatest importance to keep the house dry and warm when pollination is to be effected, and better results-both in the amount of pollen produced, and in the ease with which it is discharged from the anthers-are commonly obtained in bright sunshine. (See, also, page 227.) It is very probable that if the flowers. of fruit plants were to be kept constantly wet, very little pollination would take place. It is probable, also, that dashing rains at blossoming time wash away much of the pollen, but it is doubtful if enough of it would be lost in such passing storms

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