In the Orchard and Vineyard

New Zealand Journal of Agriculture, Volume 66, Issue 2, 15 February 1943, Page 105

In the Orchard and Vineyard

Orchard Notes

Treatment of Fireblight Disease

EVERY effort should be made : to place fruit in the hands of the consumer in , the best possible condition. . Fruit at its ■ prime is its own salesman, , and an increased demand can be expected if the consumer is receiving fruit when at its best. Much can be done by the grower to assist towards this end, and the following hints should be noted: — Make two pickings of each variety. Pick carefully. Keep the fruit when picked out of the sun. Fruit held in the shed should be in a cool, wellventilated position. After picking handle fruit expeditiously. Keep the shed free of rejects and rotting fruit. Keep the sizing-machine clean. Provide ample light for grading. Consolidate pack and keep ends of pack almost level' with case to avoid bruising when nailed up. Despatch fruit promptly after packing. Fireblight ' Fireblight is a bacterial disease caused by Erwinia amylovora. It overwinters in a more or less quiescent condition in large cankers on pear, quince and hawthorn trees. . The danger period occurs in spring with the renewal of sap movement, when the organism again becomes active and small masses of ooze exude from the overwintering cankers. This ooze is at first a sticky water-coloured fluid which gradually dries to a stiff resinous mass, amber in colour, and later becoming hard and dark coloured. Insects, especially bees, appear to be

Scale Insects

FOR the eradication of scale insects an oil spray is used (which blocks the tracheae or breathing pores) and thus asphyxiates them. The addition of nicotine will control other insects such as thrips, black-aphis, red-mite and mealy-bug. The spray should be applied in mid-February at a strength of 3 per cent, certified summer oil. This should be repeated three to four weeks later. In the latter spray add nicotine sulphate 1-800 for the other pests listed above. These spray strengths are: To each 100 gallons of spray 3 gallons summer oil. 1 pint nicotine sulphate. or to each 4 gallons of spray—--1 pint summer oil. 6 teaspoons nicotine sulphate.

readily attracted by the ooze when it first appears, and carry away with them large numbers of the organism. Where these insects visit the blossoms of host trees, blossom-infection is likely to occur on a large scale. In most seasons the period at which the ooze appears occurs just after blossoming and only the very late blossoms may become infected, but in some seasons, possibly due to early sap movement, the organism is active at an earlier period, and ooze appears coinciding with blossoming. Blossominfection then becomes rapid and extensive, due to the activities of bees and other insects, which not only cause the initial spread from ooze to blossom but from blossom to blossom. Sucking insects are able to carry the organism in their mouth parts, and should they feed on soft tissues of young shoots after having visited infected shoots infection is likely to follow. Bronze beetles are common agents in the spread of shoot infection. Pear Trees Infection is liable to spread rapidly in pear trees, the organism quickly travelling from infected blossoms or young shoots to the heavier branches, where . large cankers may be formed, and these may soon girdle branches which then die. Infection of pear trees is usually a serious matter, especially the initial attack of fireblight sustained by the tree. Infections in subsequent years seldom reach the virulency of the initial outbreak, leading to the belief that following the initial infection the trees become partly resistant. Apple Trees On apple trees, only blossom and twig infection is likely to be prevalent, branch cankers being very unusual. The spread of the organism appears to cease when the larger branches are reached. Serious loss of crop, however, may follow early blossom infection. T reatment In the treatment of the disease especial attention should be paid to pear and quince trees showing infection, and every effort should be made to cut out and destroy infection as promptly as possible. On the laterals and lighter branches the cut should be made well below the point of visible infection, and the wound swabbed with acidulated mercuric chloride* and then

coated with a protective covering such as bitumastic paint. To prevent spreading infection all tools should be dipped in a solution of formalin 1 part to 100 parts methylated spirits. In the past, blossom and twig infection on apples' was looked upon seriously, and efforts were made to cut off all infected spurs and twigs. However, there is no known instance of the organism overwintering in apples in this country, and . apart from ( infected fruits which should be picked and destroyed, little attention need be paid to infection on apple trees until the winter pruning. The destruction of all fireblight cankers on pear and quince trees, and the cutting down of adjacent hawthorn will do much to prevent fireblight infection reaching your trees during the danger period of October.

—R. G. I. HAMILTON,

District

Supervisor, Horticulture

Division, Auckland.

* See Fungus Diseases of Fruit Trees, page 36,

Citrus Notes

Passion Fruit Culture

THE culture of the passion vine, Passiflora edulis, has been undertaken commercially for a number of years in various parts of the Auckland Province.

Ten years ago, on virgin land, passion vines planted at Kerikeri, Bay of Islands, at various localities throughout the Bay of Plenty, and also near Auckland city, flourished. The vine grew profusely, and whilst the fruit was plentiful, easily grown, and readily marketed, advice given with regard to the systematic pruning, spraying and manuring of the vines was often ignored.

This industry, which was once in- a thriving condition, is now on the decline, due largely to the incidence of diseases which have wrought havoc amongst the vines. Today, the commercial passion vine grower must be prepared to carry out the maintenance of this vine in a systematic manner if success is to be achieved in its. culture. At present it is known that there is a profitable market available in the Dominion if the fruit can be successfully grown. Situation and Soil The site chosen should be accessible, that is within easy reach of the rail for transporting the fruit to distant markets or in close proximity to a centre of population. It should also be free from injurious frosts, as the vines will withstand only a few degrees of frost. The effects of frost are not only the killing of the young shoots but also result in the weakening of the vines, which subsequently often succumb to disease.

The passion vine will grow on a wide range of soils, but for commercial cropping requires a light, rich loam with good drainage. It will withstand moderate winds, provided the trellis upon which it is trained is of adequate strength. The site chosen should preferably have a slight northerly slope so that the vines . may receive maximum sunshine. Steep or broken country will greatly increase the costs of production.

Preparing the Site

Where necessary, first clear the land of fern, gorse, scrub, stone, etc. Plough the area in the autumn to a depth of between 6 and 9 inches and allow to fallow over winter. At the same time a low shelter should be planted around every two acres to be planted in vines, unless the , topography of the area makes this unnecessary. The southern

and western boundaries need most protection. The shelter recommended is Cupressus Lawsoniana, Haken saligna, Acmena floribunda, Berberis vulgaris, Pittosporium crassifolium, varieties of Feijoa sellowiana, or such other hedge as has been proved suitable for local conditions. Preparing the Soil The area should be cross ploughed in late winter (August) and an annual crop may then be sown, provided it will be harvested by early autumn (March) The soil should then be disced to . a fine tilth and a cover crop of blue lupins, 1| bushels per acre, plus 4 cwt. of superphosphate should be sown. This leguminous crop should grow over the winter and be turned in by plough or heavy discs before midSeptember in order that the area may be worked to a fine tilth prior to October, when the young passion vines should be set but. Although vines may be planted in the previous spring, this is considered inadvisable on newlybroken ground, as all previous experience with virgin soils indicates that thorough preparation of the soil is time well spent. This preparation of the soil, as for orchard establishment, is therefore essential. If this is not done, the suppression of resulting weed growth, following inadequate preparation, becomes an operation of some, magnitude. Although roots of the vine have been found occasionally at a depth of ten feet, the vine is generally regarded as surface rooting and its roots will be less injured by the implements of cultivation if the soil has been well tilled prior to the planting of the vines. Probably one of the reasons for the early success of the passion vine on virgin soils is the higher humus content of such soils. As humus becomes rapidly exhausted by clean cultivation, the annual sowing of “green manuring” cover crops to maintain the humus content of the soil is recommended. Seed Selection and Propagation It should be realised that whilst the land is being prepared, the choice of suitable seed and the raising of young passion plants are the most important undertakings of the intending planter. With all forms of horticulture, it is a well-known axiom propagate only from the best” — it is surprising the number of plants which are raised from inferior stock. Choose a wellproven vine, that has cropped consistently with a desirable type of fruit,

The fruit of the smaller purple form of Passiflora edulis is superior to that of the “mammoth” variety, which is often incompletely filled with pulp. It is important that fruits selected for seed purposes should be free from disease. * The seed boxes should have an inch of loose, well rotted, horse manure placed on the bottom; this should be pressed down and three inches of soil added. This soil should be made up of two parts turfy loam, one part leaf mould, and 1 part of coarse, clean sand. The turfy loam is generally obtained by skimming the top four to six inches off an old established pasture. This turf is stacked with the grass down for about twelve months in order to , rot and be suitable for use. The soil mixture should then preferably be sterilised by steam and 1J ounces of basic superphosphate per bushel of soil should be added. The seed from selected fruits should be separated from the pulp by rubbing with sand and then air dried. It is inadvisable to wash the seed with water. Seed should be sown about the middle of October and covered, with good sieved soil. The first seed to germinate should appear in 14 days and the main crop of seedlings should appear 21 days from planting. With a good strike lib. of seed should yield 13,000 plants. Pricking out should be done at the four leaf stage, commencing towards the end of November and being completed by mid-December. The pricking out boxes 12in x 18in should be filled with the usual pricking out soil, with well rotted horse manure on the bottom. Six rows of six young seedlings will generally fill a box. At first the seedlings should be given little water but later adequate watering should be done. By the end of January, the young plants should be

ready to set out in the field if conditions are exceptionally suitable, otherwise hold the plants in the boxes over winter, or they may be planted out in nursery rows. By this system the plants are hardened off and ready for their permanent situations by the following October. When pricking out and transplanting only strong healthy

plants should be retained. To provide for annual replacements, however, a grower should always have a box of seedlings on hand. T rellis The erection of the trellis or fence upon which the vines are to grow, should, if possible, be erected prior to the planting of the ' young vines or as soon after planting as possible. If the erection is left too late, the young vines become a mass of tangled canes, which require considerable effort to disentangle; or pruned off, represent lost growth. The trellis' should consist of strong posts, with the base treated with creosote, unless they are of a durable nature, and spaced 22 or 33 feet apart in the rows and 11 feet between the rows. The exact measurements are immaterial, provided a structure is erected which will carry a full' bearing crop and allow the passage of cultivation implements between, the rows. The posts should be 8 to 9 feet long to allow for two to three feet' in the ground and six feet above. Trellises should not be much more than 100 yards in length as long trellises increase harvesting costs. At the end of each row should be a good strainer post with a foot set in by an experienced fencer. Four No. 8 gauge wires, evenly spaced, with the highest strained along the top of the posts and the lowest at least two feet from the ground, forms a suitable framework. In order to provide vertical support for the passion vine leaders and also to strengthen the trellis, four light teatree, or bamboo stakes are required. With the young vine as the point of radiation, four of these stakes long enough to reach from the ground to the top wire should be set in fanwise by each plant. ■ These stakes vitally assist the grower in training the young vine on the trellis. ■ Careful perform-

ance of this early training is essential as it is the basis of the permanent framework of the plant. It is inadvisable to use wire netting as the vines soon become too entangled and thus cannot be properly pruned. The rows of the trellis should run as near north and south as possible so that the ripening fruit may obtain

maximum sunshine. To give the vines the maximum rooting surface, vines in adjoining rows should not be opposite each other. By . this system of planting, there will be theoretically 360 vines per acre, but in actual practice, ' by allowing for headlands, shelter, etc., 300 vines per acre can be considered an adequate average number. If vines are planted closer together, although there will be a larger number per acre, the crop per vine will probably be reduced and the crop per acre be thus unaltered. Planting If it is intended to plant two-year-old seedlings, these should be cut back in the nursery, and the roots also pruned by wrenching a few weeks before planting out. The one-year-old plants, which generally strike as well or even

better, may be taken straight from the boxes. / They will also be more inclined to bear a winter crop, two years from the time of planting. Planting should be undertaken in October, after the risks of frosts are over, and before dry weather sets in. Spread the roots carefully when planting and do not allow them to become dry during the operation. During the first few weeks there will be little growth, but by January the vines generally grow rapidly and should be trained on to the trellis at once. . Tie lightly with raffia to the framework already prepared. T raining In training passion vines on the type of trellis suggested, the aim should be to establish a main leader along each of the four stakes that have been attached to the trellis at each station. To reduce a vine to one main leader appears to be a too drastic system, resulting in loss of cropping surface and also leaving the vine too open to hail or other mortal injury. With the young vine making growth choose the four strongest shoots to tie up on to the perpendicular supports and pinch back all other shoots before they exceed three inches of growth so that the. four leaders chosen may develop maximum length and thickness during the first season. As each of these four main leaders attains sufficient length ■ it should be twisted lightly round the stakes provided and. tied in position. These leaders, as they lengthen, should be trained on to the horizontal wires, the two inner leaders to the right and left along the top wire and the two outer leaders along the second wire. It is important that this work be carefully done as the object is to form the permanent framework of the vine clean and strong. All other shoots

thrown out by the plant at ground level should be pinched back before exceeding three inches in length. In the spring following planting, the vines generally make considerable growth and training is required to keep the leaders along the main wires of the trellis. Laterals arising from these leaders will carry flowers and fruit for the new season; any secondary. leaders that may arise should be suppressed unless there is a definite place for them. Pruning During the following summer and winter the vines should carry a good crop of clean fruit and all growth be young and vigorous. It is in the following spring, namely two years from the time of planting, that the main problem of pruning first arises. The passion vine bears its fruit on the current season’s growth; thus, if left unpruned, the bearing surface is further and further' removed from the main leaders. As there is no room for unlimited horizontal expansion along the trellis, vines being 11 feet apart, these annual extensions intertwine amongst themselves, the growth of previous seasons, and that of neighbouring vines, until each vine becomes a mass of tangled growth. Unless this is prevented the vine will be shortlived owing to over-cropping and the ravages of diseases which cannot be checked by spraying owing to the denseness of each vine. To prevent this occurring, an annual pruning is necessary. This should be done in the spring months. It will be noted that along the leaders there are nodes, where new shoots—lateralsarise. Prune off all dead and dying growth, and laterals which have fruited, making the cut just beyond the second bud from the base. As passion vines often are bearing the remains of a winter crop at the time this pruning is required, there is a temptation to delay action until after harvesting that crop. By that time — Novemberthe new growth for the

summer crop is generally well advanced, vines being covered with flowers and young fruits. However, if it is necessary to delay pruning in order to harvest the later fruits of the

winter crop, it is important that pruning be continued during November and December, even if it means cutting off some of the prospective summer crop. Keep the vine as open as possible, and, with the exception of the original leaders, constantly prune off the worn-out laterals to a bud at the base. All primings should be taken out of the vineyard and burnt and the ashes returned as a manure to the vines. Little pruning should be done in the autumn on account of the tendency of the vines to die back in winter if pruned late in the season. It is difficult to prune so that a summer or winter crop only results but early spring pruning should produce a summer crop and later pruning a winter crop.

—A. M. W. GREIG,

Citri-

culturist, Auckland.

(To be continued.)

Cool Storage Notes

Cool Storage of Fruit

THE present emergency conditions make the question of cool storage of fruit a pressing one, as sufficient storage space is necessary to ensure adequate supplies being held to provide for the requirements of the markets of the Dominion throughout the season. The object of placing fruit in cool storage is to retard, as far as . possible, the physiological processes which cause its ripening and ultimate decay. Success with storage largely depends on the condition of the fruit when placed in storage. No greater mistake can be made than by placing any kind of fruit in storage, and not recognising that to be successful special treatment is required from the time the fruit is harvested until it is put into the stores. Refrigeration can check only to a limited degree, decay in fruit that is already past its prime; but it will sufficiently retard the ripening process of mature fruit of good quality to enable it to be kept for a considerable time. Fruit for long storage must be of the best quality, it must be picked at the right time, be free from blemishes and disease, and packed and handled with special care. Allowance should be made for the time which will be occupied in transit, as fruit should be timed to arrive at the store in the best possible condition. The greatest of care should be exercised in avoiding delays

that may occur between harvesting and storage. Size is another factor that has an important bearing upon the keeping quality of fruit. Over-grown specimens always deteriorate more quickly than average ones. To get the best results a good medium size for the particular variety should be chosen for long storage. To obtain a more reliable average result with Jonathan apples from year to year for short storage, only medium sizes should be held, and the flesh temperature should not be reduced under 38 deg. F. Granny Smith apples grown under New Zealand conditions should be delayed before storage and wrapped in oil wraps, if they are to be held successfully from year to year after mid-August. By attention to the above recommendations, and by carefully stacking the fruit in the storage chambers, and stacking to growers’ registered numbers wherever this is possible, strict attention to the temperature and relative humidity conditions during storage, and also by carrying out a careful examination of the stored fruit at regular intervals, the storage results throughout the season should be satisfactory.

—A. A. POWELL,

Cool Storage

Officer, Wellington,