Part 38

There are many who suppose it necessary to leave the second growth of grass undisturbed, to rot on the ground, in order to preserve the fertility of old meadows in grass where top dressing with manure is not resorted to. But such management is oftentimes extremely hurtful, and the injury is proportioned to the amount left untrodden and unfed. If the amount left standing, or laying loose upon the surface, be considerable, it makes a harbor for mice, which will, under cover of the old grass, intersect the surface of the land with paths innumerable, from which they cut all the grass that comes in their way.

MARY HOWITT’s USE OF FLOWERS.

Here is another of those beautiful gems which can never be brought to the light too often. And when more appropriately than in the middle of our spring-time, while bursting buds and fragrant blossoms are delighting every sense?

God might have made the earth bring forth Enough for great and small, The oak-tree and the cedar-tree, Without a flower at all.

We might have had enough, enough For every want of ours, For luxury, medicine, and toil, And yet have had no flowers.

The ore within the mountain mine Requireth none to grow, Nor does it need the lotus flower To make the river flow.

The clouds might give abundant rain, The nightly dews might fall, And the herb that keepeth life in man, Might yet have drunk them all.

Then wherefore, wherefore were they made And dyed with rainbow light, All fashioned with supremest grace, Upspringing day and night?

Springing in valleys green and low, And on the mountains high, And in the silent wilderness, Where no man passeth by?

Our outward life requires them not, Then wherefore had they birth? To minister delight to man— To beautify the earth.

To comfort man, to whisper hope Whene’er his faith is dim, For whoso careth for the flowers, Will much more care for Him.

WHAT ARE FLOWERS GOOD FOR?

“I have said and written a great deal to my countrymen about the cultivation of flowers, ornamental gardening, and rural embellishments; and I would read them a homily on the subject every day of every remaining year of my life, if I thought it would induce them to make this a matter of particular attention and care. When a man asks me, what is the use of shrubs and flowers, my first impulse is always, _to look under his hat and see the length of his ears_. I am heartily sick of measuring everything by a standard of mere utility and profit; and as heartily do I pity the man, who can see no good in life but in the pecuniary gain, or in the mere animal indulgences of eating and drinking.”—_Colman’s Agricultural Tour._

We protest against the sauciness of the italicized line. Mr. Colman never feels any such impulse; and if he does, he ought to suspect his own ears. Nothing is more preposterous than interflagellations among men on the matter of likes and dislikes. Every man selects _his_ ruling passion, and scoffs at such as do not grow enthusiastic with him. A market gardener rails at a florist for fol-de-rol trifles; and the florist looks at the length of the fellow’s ears who has nothing but turnips, onions, and cabages; while a big Miami farmer, who puts in his five-hundred-acre corn-patch, by way of summer amusement, regards both as small affairs. We find no fault with those who possess a super-ardent enthusiasm for flowers; but when they throw it in other people’s faces, and call them brutes and asses, for not liking pretty flowers, we think the thing has been carried quite far enough. We love good manners _along_ with pretty flowers.

THE BLIGHT IN THE PEAR-TREE.[18]

ITS CAUSE AND A REMEDY FOR IT.

The year 1844 will long be remembered for the extensive ravages of that disease hitherto denominated _fire-blight_. Beginning at the Atlantic coast, we have heard of it in Pennsylvania, Maryland, Virginia, Ohio, Kentucky, Indiana, and as far as Tennessee; and it is probable that it has been felt in every fruit-growing State in the Union where the season of 1843 was the same as that west of the Alleghany range, namely, cold in spring, dry throughout the summer, and a wet and warm fall, with early and sudden winter.

In Indiana, and Ohio the _blight_ has prevailed to such an extent as to spread dismay among cultivators; destroying entire collections—taking half the trees in large orchards—affecting both young and old trees, whether grafted or seedings in soils of every kind. Many have seen the labor and fond hope of years cut off, in one season, by an invisible destroyer, against which none could guard; because, in the conflicting opinions, none were certain whether the disease was atmospheric, insect or chemical.

I shall now proceed to describe that blight known in the western States (without pretending to identify it with the blight known in New York and New England), to examine the theories proposed for its causation, and to present what now seems to me the true cause.

I. DESCRIPTION.—Although the signs of it, as will appear in the sequel, may be detected long before the leaves put out in the spring, yet its full effects do not begin to appear until May, or if the spring be backward, until June. On the wood of the last year will be found a point where the bark is either dead and dry, or else at the same point the bark will be puffed, softened, or sappy with thickened sap—these two appearances indicating only different degrees of the same blight. Wherever the bark is dead and dry, the limb will flourish above it, make new wood, ripen its fruit, but perish the ensuing winter. In the other case, as soon as the circulation of the sap becomes active, the point described shows signs of disease, the leaf turns to a darker brown than is natural to its ordinary decay, being nearly black, and the wood perishes.

The disease, at first, blights the terminal portions of the branch; but the affection spreads gradually downward, and sometimes affects the whole trunk. The time from the first appearance of the blight to that in which any affected part dies, is various; sometimes two or three weeks—sometimes a day only; and sometimes, but rarely, even a few hours consummate the disease.

On dissecting the branch, the wood is of a dirty, brownish, yellow color; the sap thick and unctuous, of a sour disagreeable odor, like that of a fermented watermelon, on the tops of potato vines after they have been frosted. In still, moist days, where the blight is extensive in an orchard, this odor fills the air, and is disagreeably perceptible at some distance from the trees.

Sometimes the bark bursts, the sap exudes, and runs down, turning black; and its acridity will destroy vegetation on which it may drop, and shoots, at a distance from the trunk, upon which the rain washes this ichor, will soon perish. When we come to treat of the _cause_ of this disease, it will be important to remember this malignancy of the fluids.

We are carefully to distinguish these appearances, peculiar to what I suppose ought to be called _winter-blight_, from another and a _summer-blight_. In this last, the leaf is affected at first in spots; gradually the whole leaf turns russet color and drops. Along the wood may be seen the hardened trail as of a slimy insect, of an ash color. The _wood_ suffers very little by this summer-blight, and sometimes none. The winter-blight is found on almost all kinds of trees. This summer it has affected the apple, the pear, the peach, the quince, the English hawthorn, privet, black birch, Spanish chestnut, elder, and calycanthus. I enumerate the most of these kinds on the authority of J. H. James, of Urbana, Ohio, and C. W. Elliott, of Cincinnati, having observed it myself only on fruit-trees.

II. THEORIES.—A variety of theories exist as to the causes of this disease. Some are mere imaginations; some are only ingenious; and some so near to what I suppose to be the truth, that it is hardly possible to imagine how the discovery was not made.

The injury is done in the fall, but is not seen till spring or summer, or even the next fall. Thus, six months or a year intervene between the _cause_ and the _effect_—a sufficient reason for the difficulty of detecting the origin of the evil.

1. Some have alleged that the rays of the sun, passing through vapors which arise about the trees, concentrate upon the branches, and destroy them by the literal energy of fire. Were this true, the young and tender shoots would suffer first and most; all pear-trees would suffer alike; moist and hot summers would be affected with blight; herbaceous plants would suffer more than ligneous: all of which results are contrary to facts.

2. Some have supposed the soil to contain deleterious substances, or to be wanting in properties necessary to health. But in either case such a cause of the blight appears untrue, when we consider that trees suffer in all soils, rich or poor; that, in the same soil, one tree is blighted and the next tree escapes; that they will flourish for twenty years and then blight; that a tree partially diseased recovers, and thrives for ten or more years without recurrence of blight.

3. It has been attributed to violent and sudden changes of temperature in the air and of moisture in the earth; to sudden change from sward to high tillage; and the result is stated to be an “overplus” of sap, or a “surfeit.” All these causes occur every year; but the blight does not every year follow them. Changes of temperature, and violent changes in the condition of the soil, may be _allied_ with the true cause. But when _only_ these things exist, no blight follows.

4. Others have attributed the disease to over-stimulation by high manuring, or constant tillage; and it has been said that covering the roots with stones and rubbish, or laying the orchard down to grass, would prevent the evil. Facts warrant no such conclusions. Pear-trees in Gibson County, Indiana, on a clay soil, with blue slaty subsoil, were affected this year more severely than any of which we have heard. Pears in southern parts of this State, on red clay, where the ground had long been neglected, suffered as much as along the rich bottom lands of the Wabash about Vincennes. If there was any difference it was in favor of the richest land. About Mooresville, Morgan County, Indiana, pears have been generally affected, and those in grass lands _as much_ as those in open soils. Aside from these facts, it is well known that pear-trees do not blight in those seasons when they make the rankest growth more than in others. They will thrive rampantly for years, no evil arising from their luxuriance, and then suddenly die of blight.

5. It has been supposed by a few to be the effect of _age_, the disease beginning on old varieties, and propagated upon new varieties by contagion. Were this the true cause, we should expect it to be most frequently developed in those pear regions where old varieties most abound. But this disease seems to be so little known in England, that Loudon, in his elaborate _Encyclopedia of Gardening_, does not even mention it. Mr. Manning’s statement will be given further on, to the same purport.

6. Insect theory: The confidence with which eastern cultivators pronounce the cause to be an _insect_, has in part served to cover up singular discrepancies in the separate statements in respect to the ravages, and even the species of this destroyer. The _Genesee Farmer_ of July, 1843, says, “the cause of the disease was for many years a matter of dispute, and is so still by some persons; but the majority are now fully convinced that it is the work of an insect (_scolytus pyri_).” T. W. Harris, in his work on insects, speaks of the minuteness and obscure habits of this insect, as “reasons why it has eluded the researches of those persons who disbelieve in its existence as the cause of the blasting of the limbs of the _pear-tree_.” Dr. Harris evidently supposed, until so late as 1843, that this insect infested only the _pear-tree_; for he says, “the discovery of the blight-beetle in the limbs of the apple-tree, is a new fact in natural history; but it is easily accounted for, because this tree belongs not only to the same natural group, but also to the same genus as the pear-tree. It is not, therefore, surprising, that both the pear and the apple-tree should occasionally be attacked by the same insect.” [See an article in the _Massachusetts Ploughman_, summer of 1843, quoted in _Genesee Farmer_, July, 1843.]

This insect is said to eat through the _alburnum_, the hard wood, and even a part of the pith, and to destroy the branch by separation of part from part, as a saw would. On these facts, which there is no room to question, we make two remarks.

1st. That the blight thus produced is _limited_, and probably sectional or local. No account has met my eye which leads me to suppose that any considerable injury has been done by it. Mr. Manning, of Salem, Mass., in the second edition of his “Book of Flowers,” states that he has never “_had any trees affected by it_”—the blight. Yet his garden and nursery has existed for twenty years, and contained immense numbers of trees.

2d. It is very plain that neither Mr. Lowell, originally, nor Dr. Harris, nor any who describe the blight as caused by the blight-beetle, had any notion of that disease which passes by the same name in the middle and western States. The blight of the _scolytus pyri_ is a mere _girdling_ of the branches—a mechanical separation of parts; and no mention is made of the most striking facts incident to the great blight—the viscid unctuous sap; the bursting of the bark, through which it issues; and its poisonous effects on the young shoots upon which it drops.

We do not doubt the insect-blight; but we are sure that it is not _our_ blight. We feel very confident, also, that this blight, which from its devastations may be called the great blight, has been felt in New England, in connection with the insect-blight, and confounded with it, and the effects of two different causes happening to appear in conjunction, have been attributed to one, and the least influential cause. The writer in Fessenden’s _American Gardener_ (Mr. Lowell?) says of the blight, “it is sometimes so rapid in its progress, that in a few hours from its first appearance the whole tree will appear to be mortally diseased.” This is not insect-blight; for did the blight-beetle eat so _suddenly_ around the whole _trunk_? Now here is a striking appearance of the great blight, confounded with the minor blight, as we think will appear in the sequel.

This theory has stood in the way of a discovery of the true cause of the great blight; for every cultivator has gone in search of insects; they have been found in great plenty, and in great variety of species, and their harmless presence accused with all the mischief of the season. A writer in the _Farmer’s Advocate_, Jamestown, N. C., discerned the fire-blight, and traced it to “small, _red_, pellucid insects, briskly moving from place to place on the branches.” This is not the _scolytus pyri_ of Prof. Peck and Dr. Harris.

Dr. Mosher, of Cincinnati, in a letter published in the _Farmer and Gardener_ for June, 1844, describes a third insect—“_very minute brown-colored aphides_, snugly secreted in the axilla of every leaf on several small branches; … most of them were busily engaged with their proboscis inserted through the tender cuticle of this part of the _petiole_ of the leaf, feasting upon the _vital juices_ of the tree. The leaves being thus deprived of the necessary sap for nourishment and elaboration soon perished, … while all that part of the branch and trunk below, dependent upon the elaborated sap of the deadened leaves above, shrunk, turned black, and dried up,” p. 261.

Lindley, in his work on _Horticulture_, p. 42-46, has detailed experiments illustrating vegetable _perspiration_, from which we may form an idea of the amount of fluid which these “very-minute brown-colored aphides” would have to drink. A sunflower, three and a half feet high, perspired in a very warm day thirty ounces—nearly two pounds; on another day, twenty ounces. Taking the old rule, “a pint a pound,” nearly a quart of fluid was exhaled by a sunflower in twelve hours; and the vessels were still inflated with a fresh supply drawn from the roots. Admitting that the leaves of a fruit-tree have a less current of sap than a sunflower or a grape-vine, yet in the months of May and June, the amount of sap to be exhausted by these very minute brown aphides, would be so great, that if they drank it so suddenly as to cause a tree to die in a day, they would surely augment in bulk enough to be discovered without a lens. If some one had accounted for the low water in the Mississippi, in the summer of 1843, by saying that buffaloes had drank up all the upper Missouri, and cut off the supply, we should be at a loss which most to pity, the faith of the narrator, or the probable condition of the buffaloes after their feat of imbibition.

But the most curious results _follow_ these feats of suction. The limbs and trunk _below_ shrink and turn black, for want of that elaborated sap extracted by the aphides. And yet every year we perform artificially this very operation in _ringing_ or _decortication_ of branches, for the purpose of accelerating maturation or improving the fruit. Every year the _saw_ takes off a third, a half, and sometimes more, of a living tree; and the effect is to produce new shoots, not death. Is an operation which can be safely performed by man, _deadly_ when performed by an insect? Dr. Masher did not detect the insects without extreme search, and then only in colonies, on healthy branches. Do whole trees wither in a day by the mere suction of such insects? Had they been supposed to _poison_ the fluids, the theory would be less exceptionable, since poisons in minute quantities may be very malignant.

While we admit a limited mischief of insects, they can never be the cause of the prevalent blight of the middle and western States—such a blight as prevailed in and around Cincinnati in the summer of 1844—nor of that blight which prevailed in 1832. The _blight-beetle_, after most careful search and dissection, has not been found, nor any trace or passage of it. Dr. Mosher’s insect may be set aside without further remark.

I think that further observation will confirm the following conclusions:

1. Insects are frequently found feeding in various ways upon blighted trees, or on trees which afterward become so.

2. Trees are fatally blighted on which no insects are discerned feeding—neither aphides nor _scolytus pyri_.

3. Multitudes of trees have such insects on them as are in other cases supposed to cause the blight, without a sign of blight following. This has been the case in our own garden.

III. CAUSE OF THE BLIGHT.—The Indiana Horticultural Society, early in the summer of 1844, appointed a committee to collect and investigate facts on the Fire-Blight. While serving on this committee, and inquiring in all the pear-growing regions, we learned that Reuben Reagan, of Putnam County, Ind., was in possession of much information, and supposed himself to have discovered the cause of this evil; and to him we are indebted for a first suggestion of the cause. Mr. Reagan has for more than twelve years past suspected that this disease originated in the fall previous to the summer on which it declares itself. During the last winter Mr. Reagan predicted the blight, and in his pear-orchards he marked the trees that would suffer, and pointed to the spot which would be the seat of the disease; and his prognostications were strictly verified. After gathering from him all the information which a limited time would allow, we obtained from Aaron Alldredge, of Indianapolis, a nurseryman of great skill, and possessed of careful, cautious habits of observation, much corroborative information; and particularly a tabular account of the blight for nine years past in his nursery and orchard.

The spring of 1843 opened early, but cold and wet, until the last of May. The summer was both dry and cool, and trees made very little growth of new wood. Toward autumn, however, the drought ceased, copious rains saturated the ground, and warm weather started all trees into vigorous, though late, growth. At this time, while we hoped for a long fall and a late winter, on the contrary we were surprised by an early and sudden winter, and with unusual severity at the very beginning. In the West, much corn was ruined and more damaged; and hundreds of bushels of apples were caught on the trees and spoiled—one cultivator alone losing five hundred bushels. Caught in this early winter, what was the condition of fruit-trees? They were making rapid growth, every part in a state of excitement, the wood unripe, the passages of ascent and descent impleted with sap. In this condition, the fluids were suddenly frozen—the growth instantly checked; and the whole tree, from a state of great excitability, was, by one shock, rudely forced into a state of rest. Warm suns, for a time, followed severe nights. What would be the effect of this freezing and sudden thawing upon the fluids and their vessels? We have been able to find so little written upon vegetable morbid anatomy (probably from the want of access to books), that we can give but an imperfect account of the derangement produced upon the circulating fluids by congelation. We cannot state the specific changes produced by cold upon the ascending sap, or on the cambium, nor upon the elaborated descending current. There is reason to suppose that the two latter only suffer, and probably only the last. That freezing and thawing decompose the coloring matter of plants is known; but what other decomposition, if any, is effected, we know not. The effect of congelation upon the descending sap of pear and apple-trees, is to turn it to a viscid, unctuous state. It assumes a reddish brown color; becomes black by exposure to the air; is poisonous to vegetables even when applied upon the leaf. Whether in some measure this follows all degrees of congelation, or only under certain conditions, we have no means of knowing.

The effect of freezing and thawing upon the tissues and sap-vessels is better known. Congelation is accompanied with expansion; the tender vessels are either burst or lacerated; the excitability of the parts is impaired or destroyed; the air is expelled from the aëriferous cavities, and forced into the passages for fluids; and lastly, the tubes for the conveyance of fluids are obstructing by a thickening of their sides.[19] The fruit-trees, in the fall of 1843, were then brought into a morbid state—the sap thickened and diseased; the passages lacerated, obstructed, and probably, in many instances burst. The sap elaborated, and now passing down in an injured state, would descend slowly, by reason of its inspissation, the torpidity of the parts, and the injured condition of the vessels. The grosser parts, naturally the most sluggish, would tend to lodge and gradually collect at the junction of fruit-spurs, the forks of branches, or wherever the condition of the sap-vessels favored a lodgment. In some cases the passages are wholly obstructed; in others, only in part.

At length the spring approaches. In early pruning, the cultivator will find, in those trees which will ere long develop blight, that the knife is followed by an unctuous sap, and that the liber is of a greenish yellow color. These will be the first signs, and the practised eye may detect them long before a leaf is put forth.