Chapter XXI: Part 21

All Celery refuse should be destroyed by fire. Infested ground may, if suitable, be trenched, bringing the subsoil to the surface and burying the top soil containing the pupæ. Frequent rough digging and the exposure of fresh surfaces to be searched by birds will also do something to abate the number of this pest. But in bad cases it will be necessary to resort to gas-lime, which poisons the pupæ and eventually benefits the soil, although in the season immediately following its use crops may be less satisfactory than usual.

Onion Fly.—Onions are frequently attacked by the larvæ of the Onion Fly, and in some instances the entire crop is destroyed. Our illustration shows the natural size of the fly and maggot, with magnified representations of both. The fly lays six to eight eggs on an Onion plant, generally just above the ground. These eggs hatch in from five to seven days, according to the temperature, and the maggots at once burrow into the Onion. The result is soon visible in the discoloration of the leaves which turn yellow and begin to decay. Several generations of the insect, the scientific name of which is _Phorbia cepetorum_, appear in the course of a single season. A close ally is the Cabbage Root Fly (_P. brassicæ_), the destroyer of Cabbage roots.

ONION FLY AND LARVA _Anthomyia ceparum_

Among the numerous methods of preventing attack and of destroying the grubs the following are worth attention:—

Where this pest proves very troublesome it may be desirable to transfer Onion growing to new ground until the infested land has been purged of the pupæ. Instead of throwing useless Onion material on the waste heap to afford the fly a home for its eggs, every scrap should be burned. As the preparation of an Onion bed approaches completion, powdered lime well mixed with soot, in the proportion of two bushels of the former to one of the latter, may be sown evenly over the surface and raked in. Sand impregnated with paraffin sown along the drills has answered as a preventive. Vaporite is a destroyer of the pupæ; this preparation has proved deadly to ground vermin generally. Earthing up the Onions was proved by Miss Ormerod’s experiment to be effective. The objection to this procedure is the probability of enlarged necks which are not wanted. An emulsion, composed of one pint of paraffin, one pound of soft soap mixed with ten gallons of water, thoroughly churned by a hand syringe and sprayed over the young plants in a fine mist, is a valuable preventive. The dose may be repeated after rainfall, if necessary. The quantities named suffice for a small plot only. Soapsuds are destructive to the maggots, disagreeable to the fly, and beneficial to the young plants. The suds should be sprayed over the bed from a watering can on the first appearance of a yellow colour in the grass. As a final suggestion reference may be made to a singular fact which we do not profess to explain, viz. that transplanted Onions are very seldom touched by grub. The modern practice of raising seedlings under glass in January or February, and planting out in open beds in April, offers the advantage of a long season of growth combined with comparative immunity from attack by the Onion Fly.

Turnip Fly, or Flea, is well known to the gardener, and is the most troublesome of all the aërial pests of the farm, and one with which it is most difficult to cope, not only because of its general diffusion and numbers, but because it produces a succession of broods throughout the summer, and is therefore always in force, ready to devour the crop immediately it appears. The so-called ‘Fly’ is a small beetle named _Haltica (Phyllotreta) nemorum_, strongly made, and decidedly voracious. The larvæ are not to be feared, except that, of course, they in due time become beetles. In the perfect state this winged jumping insect makes havoc of the rising plant of Turnips, but the crop is only in danger while in the seed-leaf stage. It is in the spring and early summer chiefly that the ravages of these insects occasion perplexity, for they awaken from their winter torpor active and hungry, and have a ready appetite for almost any cruciferous plant. Hence we see the leaves of Radishes pierced by them, and all such weeds as Charlock, Cuckoo Flower, Hedge Garlic, and Water Cress serve them for food until the Turnip crops are on the move, when they will travel miles, even against the wind, to wreck the farmer’s hopes. The Cabbage Flea (_Haltica oleracea_) in some districts is equally troublesome, if not more so. Whole Cabbages may be destroyed by this pest, and even Hops are often ruined by it.

TURNIP FLY OR BEETLE _Haltica nemorum_ (with larva and chrysalis)

Preventive and remedial measures that can easily be carried out in a garden may be impracticable on a farm. We propose to enumerate them briefly as they occur to us, leaving the ultimate choice of weapons to those who may unfortunately find occasion to use them.

One precaution is to insure a quick germination of the seed and strong growth of the plant in its seed-leaf stage. The cotyledons are tender and tasty, perhaps sugary from Nature’s process of malting; and while the seed-leaf is assailable the _Haltica_ makes the best of the shining hour. The seed sown should be all of one age, and the newest possible, because of the need for a quick and strong growth. When a powerful artificial is sown with the seed, the quantity of seed must be increased, as a proportion may be killed by the manure. It is important always to drill Turnip seed; broadcasting seems to invite the Fly—at all events, a drilled crop is generally safer. Before sowing, the seed may be soaked in paraffin or turpentine. Of the two the latter appears to be the more successful in keeping the insects at bay.

Rolling an infested plant disturbs and weakens the insects and stimulates the young plant.

The sprinkling of slaked lime over the seedlings is at once a safe and an efficient process, and possesses the additional advantage of being beneficial to the plant. We are aware that it does not always succeed, but we are inclined to attribute the failure to a bad quality of the lime, or a careless method of employing it. There should be enough put on to make the plants white, and they will be none the worse for the whitening. Dustings of fine ashes or soot are scarcely less effective, but salt must not be used, for it injures the plants and does not hurt the beetle. All such dustings should be done in the early morning, while the plants are wet with dew. To apply a dusting at midday, when the sun shines gaily, is to waste time, and probably many of the recorded failures might be explained if we knew at what hour and in what sort of weather the work was done. Nets and sticking boards have been tried and found effectual, and yet such things are rarely used. A board thickly covered with white paint, drawn over the plot on a still, sunny day, soon becomes a black board by the myriads of _Halticas_ that jump at and remain attached to it, the victims of their extravagant love of light. Old sacks soaked in paraffin and drawn over the drills impart a disagreeable flavour to the leaves, and a very fine spray of paraffin distributed by a machine specially constructed for the purpose has proved effective.

Finally, this, in common with all other insects in the winged state, needs a dry air and some degree of warmth for its health and happiness. Many kinds of larvæ need moisture, but no winged insect can abide moisture long, and herein is a clue to the eradication of Turnip Fly. By the simple process of spraying the plant three or four times a day, until it is out of the seed-leaf, and the danger is over, it is possible in the garden to wash out the _Haltica_; and any kind of insecticide or flavouring, such as quassia, may be mingled with the water to render the plants distasteful to the insects.

The illustration on page 422 shows the Turnip Fly in its three stages, and in each case of the natural size and magnified seven diameters.

DADDY LONG LEGS _Tipula_ (in various stages)

Daddy Longlegs, or Crane Fly, in its perfect form of a fly (_Tipula oleracea_) does no harm, but the grubs, known by the familiar name of ‘leather-jackets’ owing to the toughness of their skins, are terribly destructive. During late summer and autumn the female fly deposits its eggs in large numbers in turf, in garden soil and amongst garden refuse. The eggs are hatched in a fortnight or so and the dark grubs lie in the ground through the winter, inflicting their maximum, amount of injury to young crops in spring and early summer. Where song birds are scarce the Tipula is capable of utterly destroying grass and of seriously ravaging the Kitchen Garden; but cultivation, aided by the robins, thrushes, nightingales, and other birds, will keep the insect within bounds, even after a hot summer favourable to its increase. Where this pest is known to exist, an application of Vaporite at the time of preparing ground for sowing or planting will destroy many of the grubs. The regular use of the hoe is also to be recommended, for by the disturbance of the soil the enemy is exposed to the sharp eye of the robin and other feathered gardeners.

Root-knot Eelworm.—One of the worst pests that a Cucumber-grower has to deal with manifests itself by the presence of minute warts or nodosities, chiefly on the rootlets. These warts, which are caused by the action of innumerable small thread-like worms named _Heterodera radicicola_, range from the size of a pin’s head to that of a pea, and when they are present in large numbers the total failure of the Cucumber crop is the invariable result. The eelworms are probably introduced to Cucumber-houses in infected water. Each worm is about one-seventyfifth of an inch in length and is at first coiled up inside a transparent egg. At maturity the eggs crack open, and the worms on emerging bore into the most tender rootlets, and there lay their eggs. These eggs speedily hatch inside the plant and new eelworms are produced, which traverse the rootlets in every direction.

CUCUMBER EEL-WORMS AND EGGS _Anguillulæ_

These _Heterodera_ are by no means peculiar to the Cucumber; they attack the roots of Tomatoes and Melons, and the roots, stems, and foliage of many other plants. Our illustration shows some very small Cucumber rootlets, natural size, with the eelworms in the eggs, and also emerging from and free of the empty eggshell (enlarged eighty diameters).

Immediately symptoms of the pest are apparent from the wilting of the foliage and stems, all infected plants should be removed and burned. The soil must also be cleared out and the interior of the house thoroughly washed with a solution of carbolic acid in water:—one part of the former to eight parts of the latter. To purify the infected soil, use a solution of carbolic acid (one part) and water (twenty parts) and saturate three times, at intervals of a fortnight. Another remedy is to mix weathered gas-lime freely with the soil. In either case the soil will be unfit for use for at least six weeks after treatment. When the house has been well cleansed, fresh compost should be used, to which the addition of lime and soot, mixed with the soil, will be beneficial.

MEALY BUG _Dactylopius odonidum_

Mealy Bug.—This plague is by no means confined to plants under glass. In the case of a lot of stove plants badly affected, the desperate course of committing the whole to the fire, and then repairing and painting the house, is often the cheapest in the end. We have known a Pine-grower compelled to destroy a houseful of plants that have been infested by the introduction of a plant from a buggy collection. Mealy Bug may be known by its mealy, floury, or cottony appearance. It has a great fancy for Grape vines. One of the best remedies is Gishurst Compound, prepared at the rate of eight ounces to a gallon of water, with clay added to give it the consistence of paint. Miscellaneous stove plants may be cleansed by washing with a brush and soft soap. Our illustration shows a group of Mealy Bugs natural size, with one insect magnified.

RED SPIDER _Tetranychus telarius_

Red Spider is present in almost every vinery, however well managed. A moist atmosphere is a great, though not a certain preventive; but it is not possible, without injury to the vines, to keep the air of the house always so humid that the Spider is unable to obtain a lodgment. Syringing promotes a moist atmosphere, and is unfavourable to the Red Spider, which thrives best in heat and dryness. But the most decided repellent of Spider is the use of sulphur on the hot-water pipes. This may be managed by sprinkling dry sulphur on the pipes, or by making a thick solution of sulphur, clay, and water, with which the pipes should be painted. Be careful not to raise the heat at the same time, for if the pipes are hotter than the hand can bear fumes destructive to vegetation will be given off. Melons and Cucumbers may generally be kept clear of Spider by means of the syringe only; but when Melons are ripening they must be kept rather dry, and it is very difficult indeed to finish a crop without having the plants attacked by Red Spider. Gishurst Compound answers admirably to remove Spider from house plants. The mixture should consist of one and a half or two ounces to one gallon of water, and should be applied with a sponge. The scientific name of the Red Spider is _Tetranychus telarius_. Our illustration shows one of these destructive red mites natural size, and two individuals greatly magnified.

Scale.—A very common species, found on many kinds of stove and other plants, is the _Lecanium hibernaculorum_, here illustrated on a twig, natural size, and magnified. It is brown, tumid, and commonly somewhat more than hemispherical in shape. Besides this species there is the _L. filicum_ of Ferns, the _L. hemisphoericum_ of Dracænas, the _L. rotundum_ of the Peach, and the common _L. hesperidum_, or Orange-tree Bug, which is one of the flat species, and it spreads to a great variety of plants. The Scale insect sucks the sap from plants, and in some instances the ground beneath the foliage is wet and soddened by the falling sap. Spirit of turpentine applied with a soft brush is considered to be a good remedy for Scale. It is, however, advisable (as in other remedies) to test this on a small number of plants at first. A near relative, a large brown _Coccus_, infests pomaceous trees, and is especially partial to the Pyracantha, which it often kills outright. The Scale of the Vine is _Pulvinaria_ or _Coccus vitis_. Careful washing with soap and water, and the destruction of each separate Scale as soon as seen, can be recommended for the extirpation of this pest.

COMMON SCALE _Lecanium hibernaculorum_ (natural size and enlarged)

THRIPS _Thrips minutissima_

Thrips may pursue their mischief to a great extent before they are discovered by the novice, for their minute size and their habit render them inconspicuous. But the black deposit they make reveals their existence to the experienced eye, and the debilitated condition of the plants they have attacked would soon compel attention were there no such deposit to tell the tale. The Indian Azaleas are apt to be beset by Thrips, as the Grape-vine is by Scale, the Pineapple by Mealy Bug, and the Rose by Green Aphis. Atmospheric humidity is a powerful preventive, as is also the promotion of vigorous growth by a plentiful supply of water to the roots of the plants; in fact, starvation and a dry, hot air will soon bring an attack of Thrips. Generally speaking, the best remedy is fumigation with tobacco. Or tobacco water and a solution of soft soap, together or separately, if carefully applied, speedily make an end of this troublesome pest. A special preparation may be made as follows: Take six pounds of soft soap, and dissolve in twelve gallons of water, add half a gallon of strong tobacco water, and dip the plants in the mixture. Before they become dry, dip again in pure rainwater to remove the mixture. If too large to dip, apply the mixture with the syringe, and in the course of a quarter of an hour or so syringe with pure rainwater. Our illustration shows the Thrips in the larval and winged state, natural size and greatly magnified.

Ants.—These extremely interesting insects are frequently troublesome in gardens, and in the spring of the year the small red species mars the appearance of lawns by throwing up numerous heaps of fine soil. It is easy to destroy them by dropping a mixture of Paris Green and sugar near their runs. But as Paris Green is a poison, animal life must be considered. We recommend a simple remedy which entails no danger, but it must be followed up persistently. Purchase a few common sponges, as large as a man’s fist. Dissolve one pound of Demerara sugar in two quarts of warm water. Immerse the sponges, wring out nearly all the liquid, and place them near the ant runs. Twice daily throw the sponges into hot water, and repeat the process until the ants are cleared. Nests located under walls can be destroyed by boiling water.

Caterpillars cannot often be treated in a wholesale way without injury to the plant. Hence it is usual to rely on hand-picking, and, tedious as this may be, a little perseverance will accomplish wonders. We have seen a fruit garden, literally hideous with clusters of Caterpillars in spring, completely cleared by a few days’ steady work, costing but a trifle, and only needing to be conducted so that in removing the vermin there should be no harm done to the crops. In the same way the Gooseberry grub should be disposed of. Precautions cannot be taken against Caterpillars, but the careful cultivator will in good time look for patches of eggs and clusters of young Caterpillars on the under sides of leaves, and will carefully nip off the leaves on which the colonies are feeding, and make an end of them. This enemy cannot be raked in rank and file, but must be taken in detail, as in guerilla warfare.

Earwigs are the dread of the florist, for they spoil his best Dahlias and Hollyhocks, and are too partial to Chrysanthemums. They are readily trapped, as they like to go up to a high, dry, dark retreat; hence a bit of dry moss in a small flower-pot, inverted on a stake, will entice them into your hands; and if you are determined to keep down Earwigs, this way is sure, though, perhaps, not easy, because it must be followed up morning and evening from the beginning of June onwards. The hollow stems of the Bean make good traps, as indeed do hollow stems of any kind, for Earwigs love to creep into close, dark shelters after their nocturnal meal; and the cultivator who has resolved that he will not be eaten up by them needs only to persevere, and he may depend on trapping every Earwig within the boundaries. Unfortunately, they use their wings freely, and so travel from the sluggard’s garden to find ‘fresh woods and pastures new.’

EARWIG (with wings spread, magnified)

Slugs are serious plagues to the gardener, and they sometimes appear in large numbers so suddenly as to suggest the idea that the little Slugs have come down in showers. Young crops are especially liable to injury from these vermin, and it is not easy, even in well-kept gardens, to keep them down. Constant attention is necessary, particularly in wet seasons. But here, as in the case of many other kinds of vermin, means may be adopted that will accomplish the double purpose of destroying the plague and benefiting the land; for lime, salt, soot, and nitrate of soda are certain Slug-killers, and will usually pay for their employment by their enrichment of the ground. The nice point always is to employ them advantageously. It should further be borne in mind that a Slug slightly touched by lime or salt has the power of throwing it off by means of the slimy exudation with which the creature is endowed. But if again quickly assailed in a similar manner death is certain to follow. Land made ready for sowing may be pretty well cleared of Slugs by broadcasting it with salt. Unfortunately, these destroyers are only effective in fine weather. In rainy seasons, or when a crop is rising, it is necessary to resort to trapping, and many kinds of vegetable refuse make tempting baits for Slugs. Pieces of Orange peel, suitably placed, are soon covered with the vermin, especially in the winter during intervals of frost. Cabbage leaves, sliced Turnips and Potatoes, or almost any waste vegetable may be used. The traps should be scattered about at dusk, and be gathered up in the morning, and buried in pits, or destroyed by fire.

Gas-lime is highly destructive to Slugs, but when first applied it is poisonous to plant life. An excellent method of using it is to dress the surface in autumn at the rate of from four to six cwt. per acre, and to dig the ground deeply four weeks later.

Rows of Peas are easily protected by a covering of barley sweepings, or by charcoal broken very small and flavoured with paraffin. Slaked lime, carefully used, is also employed with satisfactory results.

Snails.—In their methods of attacking garden vegetation, and in the extent of damage they cause, Snails may be placed in the same category as Slugs. During the day the Snail usually remains in hiding, emerging from rockeries and creeper-covered walls in the evening or after a shower of rain. They may be trapped by one of the methods suggested for Slugs, and preference should be given to the use of Cabbage leaves. It will, however, be safer to protect young plants by giving heavy dressings of lime or soot. Hand picking is the surest means of dealing with them, and in the winter months large numbers may be collected from among box edgings, the base of ivy-covered walls and similar shelters. Birds, especially thrushes, show a marked partiality for Snails.

Wasps are a terrible scourge in some gardens. They spoil a large quantity of fruit, and jeopardise the remainder by forcing the harvest before the crops are ready for gathering. When the localities of the Wasps’ nests are known, it is a simple task to dispose of them. Turpentine and gunpowder were formerly in vogue, especially among the younger members of the community, to whom a spice of danger is always an attractive element in the fun. But these are clumsy methods of destruction and will not compare with the far easier remedy of poisoning the colonies by means of cyanide of potassium. Dissolve one ounce of the drug in a quarter of a pint of water. This will be sufficient to destroy several nests, but it is a deadly poison, and must be kept in a place of safety. Soak a piece of rag in the fluid, and lay it over the entrance to the nest. There is no occasion to run away; not a Wasp will venture out, and those which return from foraging will not lose their tempers and find yours, but at each successive attempt to enter their home they will become feebler, until they fall near or beneath the drugged rag. After an hour or two the nest may be dug out, when every insect, including queen and pupæ, will be found dead.

If the colonies lie beyond your frontier, or their positions cannot be ascertained, the enemy must be disposed of by stratagem and in detail. One of the best modes of trapping them is to put some injured fruit beneath one of the trees, and over it a hand-light raised about three inches above the ground by stones or pieces of wood placed at the four corners. This light must have a rather large hole at the top. Upon it should rest another light from which egress is prevented, except through the apex of the lower light. After the Wasps have visited the fruit, they will rise into the first light, and gradually find their way through the opening into the one above, from which not one insect in a hundred will escape. In a trap of this kind we have seen an enormous number of Wasps and Hornets which had been lured to death within a few hours.

Another simple and effective method of destroying these pests is to pour a small quantity of ale mixed with sugar into glass jars and suspend them from branches of Pear or Plum trees. The vessels must be emptied every few days and the liquid renewed.

WIREWORM (natural size and magnified)

Wireworm is the most persistent and destructive of all the ground vermin. There are fully a dozen species of beetles the larvæ of which are known as ‘Wireworms,’ and of these the ‘Spring-Jacks,’ ‘Click-Beetles,’ and ‘Blacksmiths’—_Elater obscurus, E. lineatus_, and _E. ruficaudis_—are the most prevalent. The female beetle deposits her eggs in the earth in the height of the summer, and in due time the worms emerge and commence their depredations. These worms have a tenure of three to five years in their subterranean homes, during which time they feed voraciously, and are not very particular as to what they eat. Their muscular power renders them expert in burrowing, and they are well protected by their horny jackets. When their term of feeding is completed, they descend to a considerable depth and change into the chrysalis state, from which they come forth as jumping beetles in the course of July and August, a certain proportion remaining in the ground to complete their final change in spring. Their power of destruction is then at an end. They resort to flowers, lead a merry life for a short time, and when they pass away leave plenty of eggs to continue the race of Wireworms.

For practical purposes the Wireworm may be regarded as inhabiting every kind of soil and consuming every kind of crop. The crops it is most partial to are Grass, Potatoes, Turnips, and the juicy stems of all kinds of cereals. The larvæ may be trapped by burying in the ground pieces of Potato, or better still thick slices of Beet root; the spots to be marked, and the traps examined every few days, when the Wireworms can be destroyed. Superphosphate sown along the drills with seed has saved spring-sown crops from destruction; and Vaporite, a proprietary article, has also been used with marked success. The latter gives off a gas smelling of naphthalene which kills the Wireworms. Soot is a well-known remedy, and by its use the crops are also benefited.

Woodlice are very destructive but easily caught, and they may be completely eradicated by perseverance. When a frame or pit is infested, they can be destroyed wholesale by pouring boiling water down next the brickwork or the woodwork in the middle of the day. If this procedure does not make a clearance, recourse must be had to trapping. In common with Earwigs, they love dryness, darkness, and a snug retreat; but while a mere home suffices for Earwigs, a home with food is demanded by Woodlice. Take a thumb pot, quite dry and clean. In it place a fresh-cut slice of Potato or Apple, fill up with dry moss, and turn the whole thing over on a bed in a frame or pit. Thus you have devised a Woodlouse trap, and next morning you may knock the vermin out of it into a vessel full of hot water, or adopt any other mode of killing that may be convenient. Fifty traps may be prepared in a hundred minutes; and those who are determined to get rid of Woodlice may soon make an end of them.

Rats and Mice.—Traps are efficient while they are new, and almost any reasonably good contrivance will answer for a time, but will fail at last, or at least for a season. To keep down Rats and Mice effectually there must be invented a succession of new modes of action, for these creatures—Rats especially—are so clever that they soon see through our devices, which then fail of effect. Generally speaking, two rules may be prescribed. In the first place it is imprudent to fill up their holes or stop their runs; let them have their way. If you stop them, they will make new thoroughfares, to the further injury of the foundation; and, besides, when you are acquainted with their runs, you know where to put traps and poison for the vermin. As to the best poison, there is nothing so effectual as arsenic; but it should be employed with great care, and before it is brought on the premises the question of safe storage must be considered. A fat bloater split down and well rubbed with common white arsenic will kill a score of Rats, provided only that they will eat it. Cut it into four parts, and place these in or near their runs, and cover with tiles or boards to prevent dogs and cats obtaining them. If this fails, try bread and butter dressed with oil of rhodium and phosphorus. The oil of rhodium seems to possess an irresistible attraction for these vermin. When dry food is preferred, there is nothing so good as oatmeal; and it is a golden rule to feed the Rats for a few days with pure oatmeal, and then to mix about a fourth part of arsenic with it. Several proprietary articles are offered for the destruction of Rats. Before resorting to these means of annihilating vermin it is necessary to take steps to prevent the bodies from proving a nuisance after death. A good fox-terrier will keep a large garden free from Rats and Mice.

THE FUNGUS PESTS OF CERTAIN GARDEN PLANTS

Many of our garden plants are liable to the attacks of fungi. Cures are in most instances unknown, but in some cases preventives—which are better—have been adopted with partial or entire success. Plants raised from robust stocks, grown in suitable soil and under favourable conditions, are known to be less liable to disease than seedlings from feeble parents, or those which have been rendered weakly by deficiencies in the soil or faulty cultivation. Whether weakness is hereditary, or is attributable to a bad system, the fact remains that disease generally begins with unhealthy specimens, and these form centres of contamination from which the mischief spreads. It is, therefore, important that seed from healthy stocks should be sown, and that a vigorous constitution should be developed by good cultivation.

Anbury, Club, or Finger-and-toe.—The disease known by these various names is common in the roots of cultivated cruciferous plants such as Cabbages, Kohl Rabi, Radishes, Swedes, Turnips, &c., and also in many cruciferous weeds, including Charlock and Shepherd’s Purse. The cause of this disease is an extremely minute fungus, which may lie dormant in the soil for several years for want of a comfortable home, and when a cruciferous plant becomes available the fungus fastens on the fine roots, multiplies rapidly in the tissues, and produces malformation and decay. After the disease has made some progress insect agency frequently augments the mischief, so that on cutting open a large decaying root it is not unusual to find the interior packed with millipedes, weevils, wireworms, and other ground vermin.

Unlike the Potato disease, which spreads from plant to plant through the atmosphere, the fungus of Finger-and-toe infects the ground, and from the first spot attacked the disease spreads rapidly in all directions and in various ways. It may be carried by the soil adhering to implements or the boots of labourers. And each patch becomes a new centre of infection which is spread by digging or raking. Every scrap of infected soil, or of diseased fibre which may be added to the manure-heap, distributes the virus over a wider area, so that Finger-and-toe may suddenly appear in parts of the garden which have hitherto been free from this troublesome pest. A very simple experiment will prove the certainty and ease with which the spores may be introduced to fresh land. Macerate the tissue of old Finger-and-toe in water; use this on young isolated plants of Cabbage or Turnip and in a short time the plants will be infected.

The fungus which produces Finger-and-toe is known as _Plasmodiophora brassicæ_, and it belongs to the _Myxomycetes_, or ‘slime-fungi,’ which, as a rule, live upon decaying vegetable material. The protoplasm of the fungus ramifies among and within the tissues of the roots of attacked plants, and eventually produces an amazing number of spores so small that more than thirty millions would be required to cover a superficial inch. A microscope of great power is necessary to reveal them to human vision.

FUNGUS OF FINGER-AND-TOE DISEASE _Plasmodiophora brassicæ_

The spores are capable of resting in a state of vitality for a long time, and can easily withstand the frosts of winter. The illustration shows at A the fungus in its protoplasmic condition, and at B its ultimate sporiferous or ‘seed’-producing stage, after the protoplasm has changed to a mass of minute spores (enlarged five hundred and twenty diameters). When a spore in due course germinates, its protoplasmic contents escape through a small aperture in its wall and begin moving about of their own accord in a slow writhing manner. The movement is so much like that of the microscopic animal organism found in ponds, and called _Amœba_, that this tiny mass of moving protoplasm is called _Myxamœba_, to denote that it is an amœba-like form produced by one of the _Myxomycetes_. Each myxamœba is drawn out at one spot into a fine delicate tail or cilium, as at C, D, E, and is capable of a creeping motion in moisture. When quite free from the spores, transparent expansions or limbs extend from the bodies of the myxamœbæ, as at F, G, and when these organisms, after existing in the soil for a longer or shorter time, reach the roots of cruciferous plants, which they apparently enter through the root-hairs, they again assume the protoplasmic condition shown at A, and live within the cells, at the expense of the nurse-plant. Other cruciferous plants are less seriously damaged by the pest than are Turnips and Cabbages; but it is evident that if diseased Charlock is near Turnips, the latter are very likely to fall a prey to the disease. We advise the sowing of the best seeds, the eradication of cruciferous weeds, and the destruction by fire of all decaying Finger-and-toe material, for it is in this material that the spores of the disease rest ready for continuing the disease in the following season. It is also desirable that cruciferous plants should not be continuously grown in the same quarter—in other words, it would be prudent after an attack of Anbury not to repeat a cruciferous crop on the same ground, but to follow on with a crop of some other class.

Numerous experiments have shown that slaked lime can be relied on to destroy the spores of Finger-and-toe in infested land. An application of from fourteen to twenty-eight pounds per pole may suffice in the case of light soils, but fifty-six pounds per pole will not be too much on heavy land, and the dressing should be given either six or eighteen months before a Cabbage or Turnip crop is sown; the longer period is the more certain in its effect. Preference should be given to stone or rock lime over chalk lime. The former is much more powerful and efficient. It may be necessary to repeat the dressing twelve months after the first application. As regards the occurrence of Anbury in seed-beds, frequent transplantation is a very effectual mode of stopping its progress, for the little galls can be pinched off by the workman, and burned as he proceeds; and the plant, being invigorated by change of soil, will soon grow away from the affection. In transplanting Cabbages it is a good plan to discard and burn such plants as are obviously affected with Anbury. It is worthy of remark that in market-gardens this disease is by no means so prevalent as to interfere with the routine of cultivation, although the Cabbages, Broccoli, and Cauliflowers grown in these grounds are, under other circumstances, especially liable to attack. By ‘other circumstances’ we mean that market-gardens are generally kept under high cultivation, the land being perpetually turned and heavily manured; and these measures appear to be a preventive of Anbury, while they result in heavy crops. But on land less energetically tilled Anbury may prevail to such an extent as to interfere seriously with the order of cropping. Another very important mode of keeping down the pest consists in burning instead of burying the stumps and all other refuse of the crop that cannot be turned to account.

Confusion may be prevented if we point out that Club-root, Anbury, or Finger-and-toe—whichever name may be used—is quite distinct from an apparently similar malformation of the root which is sometimes induced by certain characteristics of soil, seed, or manure, and is in fact a case of reversion to the original wild type. Instead of a shapely, solid Turnip, the bulb is divided into a number of coarse, worthless tap-roots, caused by either poverty of the soil, careless cultivation, or a degenerated stock of seed. Those who save their own seed continuously for years are almost certain to become well acquainted with this malady. They will find a change of seed necessary, and at the same time an alteration in the routine of culture. A healthy, vigorous plant, derived from a pure seed-stock, does not easily make Finger-and-toe, but a sound root that stands for food and money.

‘Grub.’—The wart-like growths formed upon the roots of Turnip and Cabbage by the little hard beetle known as the Turnip-gall Weevil, _Ceutorhynchus pleurostigma_, are also quite distinct from Finger-and-toe. By cutting across a malformed root of Turnip or Cabbage it is usually not difficult to determine the cause of the mischief. If it is Finger-and-toe the root will be found filled with decaying matter; in the case of Weevil attack the small legless maggots, commonly called ‘Grub,’ will be brought into view; and if it is merely an instance of reversion the cut root will appear to be healthy.

Potato Disease.—The fungus which causes the Potato Disease, or ‘Blight’ as it is sometimes called, was formerly known as _Peronospora infestans_; now it is recognised by scientific authorities as _Phytophthora infestans_. The mark of its pestilent touch on the foliage, and its destructive effect on the tubers, are unfortunately too familiar in gardens and on farms. In dry seasons its energies are restricted, but the scourge is never absent, and during wet summers the parasite may do its deadly work on such a vast scale as to cause a Potato famine. Moisture is a necessity of its existence, and in rotting haulm, decayed tubers, and damp soil the spores remain in a resting condition until they are afforded an opportunity of multiplying with the marvellous rapidity that invests the disease with its terrible power. A series of six illustrations, five of which are highly magnified, will enable the reader to follow the development of _Phytophthora infestans_.[1]

No. 1.

The illustration No. 1 shows a Potato leaf on a reduced scale disfigured by the attack of the fungus. The _Phytophthora_ is sending mycelial threads (called hyphæ) in all directions through the substance of the leaf, feeding on the protoplasm of the cells and destroying the chlorophyll, or leaf-green, in those cells.

No. 2. & No. 3.

No. 2 shows the fungal threads at work. In a diseased Potato plant these threads, or mycelial hyphæ, make their way through the substance of the leaves, and down the haulm into the tubers, from which they consume the food stored there.

No. 3 exhibits the various stages of germination of one of the conidia of _Phytophthora infestans_: (_a_) the ripe conidium in water; (_b_) protoplasmic contents breaking up into blocks, which separate and escape (_c_ and _d_) as minute kidney-shaped zoospores (_e_) each with two cilia; (_f_ and _g_) the zoospore coming to rest and losing its cilia; (_h_, _i_, _j_, and _k_) successive stages of germination of the zoospore.

No. 4.

No. 4 represents a longitudinal section of Potato-stalk with germinating zoospore, the germ-tube of which has pierced the cell-wall, and is growing inside the cell, as shown at +.

No. 5. & No. 6

No. 5 affords a view of another piece of tissue of the stem of a Potato plant, and shows the hyphæ of _Phytophthora infestans_ running in the cell-walls; (_a_) nucleus of a cell; the other contents shown are crystals and chlorophyll corpuscles.

No. 6 is a section of a Potato tuber: A, the cell-walls; B, the starch grains; C, the mycelial hyphæ.

Spraying Potato plants twice or thrice with Bordeaux mixture has proved effective in warding off the attack of _Phytophthora infestans_, and the practice is now freely adopted, especially in humid districts. The first application should be given towards the end of June or early in July, immediately the haulm is sufficiently developed. The Bordeaux mixture is made in the proportion of four pounds of pure copper sulphate and two pounds of quicklime to forty gallons of water. The foregoing quantities will give what is known as the _one per cent._ mixture. For the _two per cent._ mixture the quantities of copper sulphate and quicklime must be doubled, but the amount of water should remain at forty gallons. In its effect on the fungus, however, little difference is to be found between the two solutions. The copper sulphate is stirred into a few gallons of hot water placed in a wooden tub or earthenware vessel. When quite dissolved, add twenty or thirty gallons of cold water. The lime, which must be freshly burnt quicklime, is then slaked in another vessel and thoroughly stirred with two or three gallons of water until it is of the consistency of thin cream. As soon as the liquid is quite cold, filter it through coarse sacking into the copper sulphate solution and add water to make a total of forty gallons. To be effective, Bordeaux mixture must be applied in the form of a fine spray, and not with a coarse-holed syringe.

The Burgundy mixture, the use of which is preferred by some, acts in a very similar manner to the Bordeaux mixture, and is made in the same way as the latter, except that washing soda (five pounds) is substituted for quicklime.

Those who leave Potatoes to rot in the ground because the crop is not worth digging, or who bury diseased haulm and tubers in a shallow trench, under the impression that it is a safe way of getting rid of worthless vegetation, are simply storing _Phytophthora_ for another attack in the event of Potatoes being planted in the same land again. If buried at all, it must be at a considerable depth, but the effectual method is to destroy all Potato refuse by fire.

Wart Disease (Black Scab) of Potatoes (_Synchytrium endobioticum_, Percival).—This extremely infectious and destructive disease of the Potato has been given a variety of names in different parts of the country, but it is now generally known as the Wart or Cauliflower Disease, the latter term being attributable to the Cauliflower-like appearance of the outgrowth of the fungus. This outgrowth first shows in the eyes of the young Potato in the form of small wrinkled warts. These multiply and combine, thus creating a dark spongy scab which eventually decomposes. Where the disease is very rife it attacks haulm as well as tubers, and a yellowish-green mass may sometimes be found just above or just below the surface of the soil. As a rule, however, no outward indication of its existence is to be seen in the crop during the early stages of growth, but towards the end of the season the haulm of badly diseased plants often retains a fresh green appearance when the foliage of others, which are healthy or only slightly attacked, is dying off.

Infection is perhaps most commonly spread by the planting of diseased tubers. Another frequent means of dissemination is caused by consigning infected haulm to the waste heap instead of to the fire. The spores may also be introduced in manure from animals fed on diseased Potatoes in a raw state, and they may even be carried from one plot to another on garden implements or the boots of those who walk across infected ground. Immediately any sign of the disease is observed it should be dealt with promptly and in no uncertain manner. Every particle of the infected material must be carefully collected and burned. Dig out the soil around all diseased plants and burn this also. On infected land it is important that some crop other than Potatoes be taken in the season following the outbreak, and, if possible, such land should not be used for Potatoes for at least five or six years. But where garden space is limited, a contaminated plot may have to be requisitioned for Potatoes within two or three years. In such cases it is an excellent plan to dust the sets freely with sulphur at the time of planting and to repeat the application before earthing up.

Although for some years the unremitting labour of experts has been devoted to the investigation of Wart Disease, and innumerable experiments have been undertaken, no effectual remedy has yet been discovered. It has been found, however, that certain Potatoes are resistant to the disease, and by order of the Ministry of Agriculture and Fisheries none but ‘immune’ varieties may be planted in districts scheduled as infected areas. A notification of the existence of Wart Disease must be made to the Ministry immediately it is observed.

Leaf Spot of Celery.—This disease, which is caused by a minute fungus (_Septoria apii_, Chester), is capable of inflicting serious damage to the Celery crop unless prompt measures are taken to exterminate it. The first sign of its appearance is to be found in the leaves in the form of small brown patches. These are, however, quite distinct from the spots deficient of leaf-green due to the attack of the Celery Fly larvæ, and on close examination may be recognised by the presence of a number of very small black points. From the leaves the fungus quickly spreads over the leaf-stalks and finally to the heart of the plant, ending in its total collapse. So rapid is the multiplication of the spores, especially in moist weather, that a few diseased plants are capable of infecting a large plot within two or three weeks. Immediately discoloration of a leaf is noticed the affected portion of the plant should be picked off. If the stage of the disease is so far advanced that the outer leaf-stalks have become decayed, the entire plant should be removed and destroyed. It is of the utmost importance that every particle of diseased material be consigned to the fire and not to the waste heap. Spraying three or four times with Bordeaux mixture at intervals of two or three weeks may be helpful in the case of a light attack, but the safest course always is to remove and destroy any plant on which the fungus is found. One of the most frequent means of introducing Leaf Spot of Celery is through the use of infected seed, and therefore only seed which has been treated for the destruction of the fungus should be sown.

Lettuce Mildew.—This fungus is named _Bremia lactucæ_, formerly known as _Peronospora ganglioniformis_, and is sometimes of the most destructive character. It covers Lettuce leaves with a fine white bloom, which decomposes the leaves, and makes them adhere together in one putrescent mass. It should be looked for in its earliest stages, and be hand-picked and burned. Old Lettuce stumps should likewise be pulled and burned, otherwise they may harbour the disease.

Onion Mildew is caused by the fungus _Peronospora Schleideni_, which is occasionally disastrous in its effects, more especially in cold, wet seasons. It occurs at uncertain intervals of time with extraordinary virulence, and then utterly destroys the crops. Autumn sowing is considered a good preventive by many growers, as the disease is frequently fatal to spring seedlings. In its early stages the mildew may be successfully dealt with by freely dusting the plants with flowers of sulphur when wet with dew, or by the application of sulphide of potassium in the proportion of one ounce to a gallon of water. Otherwise all diseased material should be removed and burned.

Pea Disease.—Although garden Peas often suffer badly from the attacks of _Peronospora viciæ_, which is the cause of Pea Mould, yet the most deadly foe to Peas, especially late Peas, is a fungus of a totally different character. To such an extent does the Pea Blight sometimes devastate the later Peas, particularly in dry summers, that the whole crop is in some gardens completely annihilated. The name of the fungus of the Pea Blight or Mildew is _Erysiphe Martii_. Its attack is often made suddenly; the leaves then lose their natural green colour, and become yellowish and densely coated with a fine white bloom; this bloom becomes at length dusted over with innumerable minute black bodies, which look, under a lens, like tiny spiders’-eggs in the web. These little black bodies are filled with extremely small transparent vessels, and each vessel contains from four to eight spores or seeds. Our illustration shows this _Erysiphe_ enlarged one hundred diameters, with two of the vessels containing the spores removed from the globular spots and further enlarged. The only safe way of dealing with infested Pea plants is to burn them. Many other species of fungi belonging to the same genus attack fruit trees, vegetables, and garden flowers. It is, however, unnecessary to illustrate them, as they more or less resemble the fungus of Pea Blight. They all arise from an _Oïdium_ condition, similar to the _Oïdium_ or Mildew of the Vine, and it is in this condition alone, as in the case of the Vine, that they can be reached by any fungicide.

FUNGUS OF PEA MILDEW _Erysiphe Martii_

Tomato Diseases.—The Tomato, like its near relative, the Potato, is subject to a number of destructive diseases which spread rapidly if allowed to become established. The most serious of these epidemics are found among crops cultivated under glass, where the forcing treatment which they often receive, and the soil and atmospheric conditions, render the plants abnormally susceptible to the attacks of fungi and insect pests. Perhaps the most virulent forms of disease with which the Tomato-grower is troubled arise from the attacks of parasitic fungi and bacteria, among which the following are most frequently met with:—

SLEEPY DISEASE, or TOMATO WILT.—In its outward symptoms and effects this disease somewhat resembles an attack of Root-knot Eelworm, but the swellings are absent from the root. The plants for a time appear quite vigorous and healthy, but when full-grown they suddenly wilt and die within a few days. The malady is caused by the fungus _Fusarium lycopersici_, which first invades the roots and ultimately eats its way through the substance of the collar or stem near the surface of the soil, in consequence of which the supply of water taken up by the roots is cut off from the leaves above ground and the plant collapses. There is no remedy for the Sleepy Disease of Tomato, and plants which bear evidence of infection should be carefully dug up and burned.