THE HOME GARDEN GARDEN IN MARCH

New Zealand Journal of Agriculture, Volume 94, Issue 2, 15 February 1957, Page 185

THE HOME GARDEN GARDEN IN MARCH

kyiARCH is usually a quiet month in the vegetable garden, because the main winter * crops such as savoy cabbage, broccoli or winter cauliflower, silver beet, and the taprooted crops such as carrots, parsnips and beetroot are. well established and there is usually comparatively little sowing or planting to be done. Work usually consists mainly of keeping down weeds and controlling insect pests and diseases, tidying the garden, watering, or feeding with liquid manure. In this article A. G. Kennedy, Horticultural Instructor, Department of Agriculture, Dunedin, deals with work in the vegetable garden in March and concludes a discussion of insect pests and their control which was begun in last month's notes. « _ g>.■;

'T'OWARD the end of the month in J- districts where winters are not too severe a sowing can be made of carrots and onions for spring use. Spinach can still be sown for late autumn or winter use in most gardens, and cabbage, silver beet, and, in reasonably favourable situations, cauliflower, can be set out. In specially favoured districts where soil conditions are good, particularly in the north, sowings can be made of beetroot, turnips, and radishes. Celery should be blanched as it reaches maturity or near maturity. Potatoes should be dug when mature. If blight is prevalent in the district, the top growth should be sprayed with bordeaux or a suitable certified fungi-

cide. A sowing of parsley can be made to ensure continuity of supply if seed has not been sown since early spring. Earlier-sown crops, such as lettuce, spinach, and silver beet, can be thinned or seedlings can be planted out. Where aphids infest crops they should be sprayed with nicotine sulphate, lindane, or HETP. If red spider mite is troublesome, it can be controlled by spraying with HETP or one of the certified miticides now on the market. Most relatively active insects such as caterpillars, green vegetable bugs, vegetable weevil, and their larvae can be controlled by DDT dusts or sprays. Shallots and onions can be harvested and stored in a dry, airy place. The

pods of beans and peas should be gathered before they are fully mature so t at t e growth of the plants will not be checked. Vegetables intended or winter and spring use such as cauliflower, broccoli, leeks savoy cabbage, and silver beet, should be kept weed free, and where necessary ed ith liquid manure to ensure that good growth is maintained. The compost heap should be built up and rubbish infested with insect pests or bearing the spores of long-lived or highly resistant diseases should be burnt. Carrots Carrots do not over winter well in districts where winter temperatures are low, and in Canterbury and districts farther south autumn sowing i s rarely advisable. In districts where winter temperatures are relatively mild home gardeners desiring early spring carrots should make a sowing about the end of March. The seed-bed for carrots should be well drained and worked down to a fl ne tilth. Where drainage is poor it is advisable to make a raised bed, and for convenience in cultivating and harvesting the bed should be not more

than 3ft. wide. Soil heavily manured for a previous, crop is best and sandy or light loams are especially suitable for autumn crops. Superphosphate at about 2oz. a square yard is likely to give good results on most soils that have been well cared for or a complete fertiliser can be applied. Seed should be sown thinly Jin. to Jin. deep, according to whether the soil is heavy or light, in rows about 12in. apart. If the soil is light and free, there should be no need to thin the seedlings, but on heavier soils the plants can be thinned to about 2in. apart. If thinning is delayed, the thinnings may be used for soups and stews. A quarter of an ounce of seed will sow about 100 ft. of row. An early or quick maturing variety of carrot should be chosen for autumn sowing. A variety such as Early Horn will be found suitable. Celery In most home gardens the main crop of the self-blanching type of celery will be nearly mature or ready for blanching in March. Comparatively few home gardeners; except in the colder districts, now grow the older,

non-self-blanching type of celery, as it is usually slower and more difficult to blanch than strains of the selfblanching type. However, the green types are usually hardier and more robust and the texture and flavour of good varieties are superior to those of self-blanching types. Green celery has a higher vitamin content than blanched celery. Red strains of celery, though not much seen in home gardens now, are particularly hardy. Most self-blanching varieties can be blanched in from about 10 to 21 days, but with the non-self-blanching or green varieties blanching may take about 14 to 40 days according to variety, temperature, and the method adopted, that is, the extent of the blanching desired and whether it is done in stages. Blanching reduces the rather acrid flavour that some varieties of celery have when immature. Blanching is caused either by the failure of the green colouring matter to develop or more commonly by its disappearance after it has been formed, particularly with green varieties. Self-blanching celery is usually blanched by placing lOin. or 12in. x lin. boards, held in place by pegs, round the sides of the bed. Suitably

stiffened paper such as that used by builders (for example, laminated

paper tarred on the inside and strengthened by fibre) can be used if desired in place of boards. Non-self-blanching celery can be blanched similarly, but as a much longer period is required for blanching, it is usually either wrapped individually with stout paper held with string or elastic bands or earthed up in fine weather with clean, free-working, reasonably dry soil which preferably should contain little organic matter likely to cause rots and be free from the eggs of slugs or similar harmful creatures. Small or decaying outer stems should be removed first.

Blanching by Earthing up

Earthing up is the most difficult way of blanching. When it is finished the banked earth should be ridge shaped and the soil surface should be beaten smooth with a spade to shed rain. Under wet conditions rots may develop if soil remains touching the inner stalks after earthing up is completed; stems should therefore be drawn together when the soil is packed round them.

Though it is sometimes claimed that the quality of celery blanched by earthing up is superior to that of celery blanched by boards or paper, blanching with clean, odourless paper is quite satisfactory. A long strip of strong paper should be placed along the sides of the bed and held in position with heavy arched 10- or 12-gauge wire pins or hoops.

Rots often develop in soil-blanched celery in hot weather and blanching with soil is therefore most satisfactory in cool districts or in late autumn. As blanching causes a reduction in chlorophyll (the green colouring matter), it tends to check growth and therefore should not be begun until the plants are fairly mature. If, however, a good head of leaves is left at the top and if where soil is used for blanching it is not too tightly packed, plants will continue growing. Care should be taken when earthing up with soil to avoid getting lumps into the centres of plants, where damage may be caused to the developing hearts. .

Self-blanching varieties contain very little chlorophyll in their leaf stems and can be blanched very quickly and simply with paper or boards. Blanching with soil is rarely practised with them, so the operation of blanching has little effect on their growth. The exclusion of light tends to make the leaf stalks more crisp and lengthens growth of the heart, which at the same time usually enlarges to some extent.

Pithiness

Pithiness is a common fault of celery and is caused by the break-down of the thin-walled cells that make up the substance of the leaf stem (as distinct from its outside and connective tissue).

It may be the result of growing conditions or it may be due to a weakness in the variety. Pithiness resulting from conditions of growth is responsible for a great deal of loss in both commercial' and home-grown celery. Pithiness caused by growing conditions is mainly found in the outer leaf stalks and increases as the plants mature, whereas pithiness which is inherent in the variety is equally distributed throughout the plant.

Home gardeners who have a large planting of celery and who intend to harvest it over a long period can begin blanching when the plants , are about half to two-thirds grown. Plants for salad use are best harvested without delay after the blanching material has been removed. The fibrous roots should be cut with a sharp knife or spade just below the disc-like stem or crown, which should afterward be trimmed with a sharp knife. Poor, coarse, or pithy outer leaf stems should then be removed. With ■ most self-blanching varieties all the outer leaves have to be removed, but if a first-class variety is well grown and is harvested at the right time, few outer leaves need be discarded.

Insect Pests of Vegetables and Their Control

(Continued from last month's issue.)

Grass Caterpillars (See grass-grubs and subterranean grass caterpillars.) Grass-grub and Cockchafer Beetles There are a number of species of grass-grub, but the adult of the species commonly causing damage is a shiny brown insect usually about Jin., to jin. long. Beetles, may be found in the soil from September. The first usually emerge in late November and the last usually early in February. They feed on the leaves and flowers of a wide range of plants. Grass-grubs and beetles are, howev e r, usually, troublesome in the vegetable garden only on soil newly brought into cultivation.

The eggs are laid in clusters of from 3 to 40 a few inches below the ground surface. They are tiny, oval, and coated with a sticky fluid, which enables them to adhere to dry objects. Eggs hatch in about 2 to 3 weeks and the grubs go through three stages, gradually increasing in size and doing ever greater damage to roots until usually from about mid-May to October they change into beetles. . Small areas such as lawns and strawberry beds can be proofed against grass-grubs by applying DDT or lindane. DDT (100 per cent.) can be used at about 3oz. to 4oz. sprayed or dusted in a carrier (such as dry sand) to § acre. Above-ground parts v can be

protected from beetle injury by spraying them with DDT.

Grasshoppers (For control see *crickets.) Green Fly (See *aphids.) Green Vegetable Bug Green vegetable bugs suck the sap of many kinds of plants, doing great damage. Their eggs, which are about the size of a pinhead and pale yellow at first, later turning reddish brown, occur in rafts of from 40 to 80 eggs and hatch under favourable conditions in about 10 days. The somewhat spherical young bugs (nymphs) which appear develop in a succession of moults, during which they might be brightly coloured (red, orange, yellow, black, and green). The adults appear after the fifth moult. As yet the green vegetable, bug has not spread farther south than the northern part of the South Island. Control Important control measures include the destruction before October of weeds and rubbish on which the adults, which are then usually a

dullish hue, may have overwintered and the destruction in spring and early summer of the egg rafts. DDT dusts and sprays give good control, though not as immediate as that of HETP at 1 : 400 (1 fl. oz. in 2| gallons of water) or TEPP 38 per cent. (2 teaspoons to 4 gallons). Several days may elapse before DDT treatments are fully effective. HETP or derris dust should be used on edible produce during the 21 days before harvesting to avoid risk from residues of poison. HETP at 1 : 400 may scorch the leaves of some plants, particularly peas, broad beans, lettuces, tomatoes, and egg plants. It should not be used on them without a trial first at a strength of about 1 in 800. Grubs (See grass-grubs, ’"carrot rust fly (larvae), *crane fly (larvae), vegetable weevil (larvae), and wireworms.) Hoppers (See leaf hoppers, *crickets, and *collembolas.) Leaf Hoppers Leaf hoppers are narrow-bodied sucking insects about Jin. long, usually yellowish green or buff, with wings that fold to form a ridge. The young are wingless. These insects hop when disturbed. They cause a blotching or

yellowing of the foliage and occasionally a fine spotting or peppering. Control Leaf hoppers can be controlled by summer oil, J pint to 5 gallons of water plus 1 fl. oz. of nicotine sulphate, or by DDT dusts or sprays. Leather Jackets (See * crane fly (larvae).) Leaf Miners Leaf miners are the larvae or grubs of small flies which tunnel the leaves of various plants. Silver beet is commonly attacked. Control Protection against . the egg laying flies can be given by lindane or DDT sprays. Control of the tunnelling larvae can usually be obtained by lindane sprays. May Beetles (See grass-grub (cockchafer beetle) .) Maggots The maggots of various flies are often found on decaying plant tissue and in particular white maggots or eelworm-like creatures are sometimes

found on decaying plant tissue where fowl manure has been applied. Most of these maggots eat only decaying tissue. (See also larvae of the vegetable weevil, *carrot rust fly, *crane fly, and *bulb fly.) Millepedes Millepedes are sometimes wrongly called wireworms from their hard, wiry appearance. They are also often confused by home gardeners with centipedes, to which they are allied but from which they differ in having two pairs of legs to each body segment instead of one pair, bodies more rounded in cross-section, no poison legs, shorter antennae, and no distinct head. They are sluggish and tend to curl up when disturbed, whereas centipedes usually , escape by running. Control Control, apart from clean cultivation and the removal of rotting or damaged vegetation in which they may breed, consists of trapping as recommended for the control of wireworms or applying lindane or DDT dusts or dieldrin to the soil. Mites Mites are allied to spiders and ticks and differ from true insects in many respects. For instance, they have no wings, no distinct head, the thorax and abdomen are continuous, and the

adult has four pairs of legs (though in the nymph stage, like insects, only three).

They may be translucent, whitish or yellowish, pink, green, brown, red brown, red, or purple. Mites are tiny and some cannot be seen with the unaided eye. Only a few species are troublesome in the vegetable garden.

One of the most troublesome of these is the red spider mite, which gets its name from its habit of webbing the under sides of leaves. In late summer or autumn it turns from its early season green or a yellow-green to bright red. Its increase, like that of most other species of mite, is favoured by hot, dry weather. Control

Miticides now available are most effective, but spraying with TEPP (containing not less than 38 per cent, of TEPP) at 2 teaspoons to 4 gallons of water or with HETP (containing not less than 15 per cent, of TEPP) at 4 teaspoons to 4 gallons of water, is also effective. Summer oil at 1/3 pint to 4 gallons of water can also be used. These substances are also effective against clover mites, which occasionally migrate and stay for a time on horticultural crops, and red-legged earth mites, which attack vegetable crops in some districts. DDT dusts and sprays are also effective against both these mites (but not against red spider mite). The removal of weeds on which the mites feed and multiply .is an important control measure.

Onion Fly (See *bulb fly (larvae).) Potato Tuber Moth

The caterpillar of the potato tuber moth is pinkish white or greenish, up to fin. long, and has a dark brown head. It causes two distinct types of injury. First, early in the season, when young plants may be destroyed by the grubs feeding on the leaves and tunnelling into the stems; secondly, to the tubers if they are exposed while growing or if they are allowed to remain in the field for long after digging. Serious infestation of the tubers may also occur after they have been stored. The moth, which is small, light greyish brown, and about fin. long, flies at night. It lays 20 to 30 eggs, usually in the eyes of the tubers, but also on the leaves. The caterpillars which hatch out feed on the leaves and burrow down through the leaf stems into the stems. Control Potato tuber moth caterpillars can be controlled on the growing crop by a 2 per cent. DDD or DDT dust or by sprays of 50 per cent. DDT or 25 per cent. DDD wettable powder at |oz., to 4 gallons of water. Tubers can be protected when stored before planting by dusting them with 2 per cent. DDD or DDT dust.

Treated potatoes used for eating should be washed carefully before any further preparation is done. Tubers should not be left exposed, especially after digging. While the plants are growing the tubers should be kept well earthed up. Tubers infested with caterpillars should not be planted. Red Spider Mites (See mites.) Red-legged Earth Mites (See mites.) Root Aphids Root aphids are a species of aphids which live in the soil. They are globular, greyish yellow, mealy insects about the size of a pinhead. They suck the sap from the roots, causing the leaves to turn yellow. In severe attacks the plants may wilt and die. Control Root aphids can be controlled by crop rotation and applying one of the following at about 3 pints to the square yard: Nicotine sulphate (1 fl. oz. in 4 gallons of water to which 2oz. of soft soap has been added). HETP (4 teaspoons to 4 gallons of water) or. TEPP containing not less than 38 per cent, of TEPP (2 teaspoons to 4 gallons of water). ~. - Dieldrin and lindane should also give control. ~s r , .' . *ln home garden article in last month’s issue. ■ .

Root Knot Eelworm » (See *eelworm.) Slaters Slaters are also known as pill bugs or woodlice and, with certain crabs, are among the few crustaceans that are able to live fairly successfully on land. They can survive only by living in moist places, as they breathe by gills. The young are carried in specially modified body parts on the under sides of the females. Slaters are nocturnal and mainly scavengers, but are occasionally carnivorous and may also damage seedlings or tender growth. Control Spraying or dusting the insects’ runways with DDT will give control. Slugs and Snails Slugs and snails are molluscs, as are cockles, clams, oysters, octopuses, and squids. There are several species each differing in colour and size, but their habits generally are similar. They are voracious, mainly nocturnal feeders and shelter in cool, moist situations in daytime. The feeding habits of the various species differ slightly. Some eat plant parts well above ground, others at soil level, and others tunnel and eat basal parts, tubers, or lower roots. In dry or freezing weather slugs usually burrow into the soil, emerging whenever temperatures and moisture are favourable. Snails usually hibernate during severe winter weather, usually in dry, sheltered situations.

Slugs and snails are difficult to control in damp conditions where growth is heavy and are usually most destructive in wot seasons. As they are hermaphrodite, every individual can lay eggs.

„ t , Control The best control is a bait of loz. of metaldehyde mixed with 31b. to 41b. of bran or similar feeding stuff and broadcast thinly or placed in small heaps about 12in. apart over infested

areas on a mild evening when the soil is damp. Bait left in heaps should be covered with material such as small pieces of wood to protect it from birds and prevent rain reducing its efficacy; if so protected, it will remain

effective for weeks. Some species of slugs and snails tend to return night after night to the feed they have become accustomed to and as far as practicable baits should be applied before they have acquired the

taste tor other food. Metaldehyde is attractive to them and quick acting, making them incapable of movement, though if they have not had a lethal dose they recover to some extent the next day and, unless caught by sun or birds or other enemies, may escape. In small gardens slugs and snails can also be controlled by using a torch and spearing them with a length of sharpened wire at night and dropping them in a bucket, of hot or salty water. They can also be snipped with scissors. , Copper sulphate has also proved effective as a contact poison, though it is injurious to the foliage of many plants. Copper sulphate should be dehydrated by heating it until it is finely powdered and almost white, and then mixed with about nine times', its weight of hydrated lime. The mixture 1 should be broadcast

on a mild evening on the area frequented by the slugs or snails. Alternatively finely powdered copper sulphate can be mixed with equal parts of lime or fertiliser and broadcast thinly.

Springtails (See *collembolas.) Stem-borer Caterpillars Tomatoes are often attacked by the stem-borer caterpillar, which is usually about Jin. long and greyish green to pink with a dark head. The adult moth, is small, greyish brown, and lays up to 300 eggs on the foliage or stems of the plants, usually during early spring. . The caterpillars which hatch out bore into the stems or leaf stalks, hollowing them and causing the plants to collapse. Control For control, the plants should be sprayed from planting out and at fortnightly intervals with 50 per cent. DDT wettable powder or 25 per cent. DDD wettable powder at Joz. to 4 gallons of water. Old tomato plants should be burnt and potatoes growing nearby should also be sprayed with DDD or DDT. Subterranean Grass Caterpillars Subterranean caterpillars are often confused with grass-grubs, but are the larvae of harmless moths about lin. long with wings variably marked but usually shaded black, brown, and tawny. The moths are rather sluggish and at night are often attracted to lights in houses. The different species appear at different times of the year.

The eggs of the most destructive species are small, oval, and usually laid in October. They hatch in 3 to 5 weeks. They are white when first laid, but most soon turn jet black.

The caterpillars are greyish black. They are very small in November, but up to 4in. long by about the end of the following August. During the day they lie in a tunnel they make up to about lOin. deep, but emerge at night, usually to eat grass foliage and occasionally the foliage of other plants.

Control

The subterranean caterpillar can be controlled to some extent by the use of the bait recommended for cutworms, but best results are obtained from use of DDT or lindane used according to the manufacturer’s instructions.

Surface Caterpillars

(See *cutworms and subterranean grass caterpillars.)

Thrips

There are several species of thrips, but generally they are minute (l/15in. to l/25in. long), elongated, and rather pointed at both ends. The adults, which are usually yellowish brown to brown or black, have two pairs of narrow, fringed wings, which enable them to fly considerable distances. The nymphs resemble the adults in shape, but are wingless, usually green, yellow, or yellowish brown and do not move far from their feeding area.

Thrips rasp the leaves and suck the sap, often producing on plants such as tomatoes a silvery effect. They are favoured by warm weather and attack a great range of flowers, fruit, and vegetables, often spreading disease.

Control

Thrips can be controlled fairly effectively by DDT dust or spray or TEPP or HETP spray.

Vegetable Weevil x and Grub

The vegetable weevil is dark brown or greyish brown, about l/3in. long, and rather slim with a typical snout. It has a greyish white V on the back. The fully grown grub is Jin. long, plump, legless, and sluggish, green to

greyish green, and has a blackish brown head. Adults hide during the day, usually about the bases of plants. The weevils are particularly destructive to carrots, beetroot, lettuces, potatoes, tomatoes, and turnips, and feed on a wide variety of weeds. Crowns of seedlings are commonly eaten out. Control To control the weevil, clean cultivation should be practised, though destruction of weeds late in the season will cause the weevils to migrate to crop plants. A poison bait as advised for cutworms or DDT dust or spray can be used. If an insecticide is needed during the final 21 days before harvesting, derris should be used. White Butterfly (See * caterpillars.) White Fly White flies are rarely troublesome in the vegetable garden, though they sometimes attack tomatoes under glass. When they are numerous plants become sticky and blackened by the growth of a sooty mould which develops on the copious quantities of honey dew they secrete.

Eggs are laid on the under side of foliage, each egg having a short stalk inserted into the leaf tissue. The young, oval insect is at first mobile, but later settles down, becomes flat and begins to feed. Later it changes to another form without legs and antennae and it resembles a scale insect at this stage, but it differs because of the erect spine-like development which arises from the flat upper surface, which is raised on a thickened margin or wall. The winged insect is common and may be very numerous in summer. Control Control under glass is by fumigation with tetrachlorethane or spraying with malathion or DDT.

Weevil (See vegetable weevil, *bean weevil.) Weta (See *crickets.) Wireworms Wireworms are worm-like grubs, but are hard and wiry with a segmented outer casing, usually reddish brown or brownish black. They have three pairs of legs behind their heads, which have powerful jaws with which they eat germinating seeds, plant roots, tubers, insects, or even other wireworms. They are the grubs of long, comparatively narrow, hard black beetles. These beetles usually can be distinguished from the beneficial carabids (hunting or ground beetles) by the lack of pincer-like jaws and metallic colours and by the apparatus on the under side of the first two segments of their thorax (the middle segment of the body) which enables them when turned on their backs to right themselves with a click, from which has arisen the common name of click beetle. Control In the past for the home gardener control of wireworms has usually consisted of clearing away all rubbish likely to harbour the beetles and the use of baits such as potatoes, seed, or vegetable parts buried an inch or two under the ground. and marked with a stick. After a few days the baits are dug up and the wireworms attracted to them destroyed.

In small areas the method is fairly successful on fallow ground, if persevered with, but the most effective control is to dress the soil with either dieldrin or aldrin, DDT, or lindane (sometimes sold mixed with fertiliser).

*ln home garden article in last month's issue. .

* In home garden article in last month’s issue.

*ln home garden article in last month’s issue.

* In home garden article in last month’s issue.