Horticultural Instruction.

New Zealand Journal of Agriculture, Volume 58, Issue 2, 20 February 1939, Page 166

Horticultural Instruction.

Contributed by Officers of the Horticulture Division.

Orchard Notes.

Harvesting the Main Crops.

TXTyORK during the'coming month WORK be mainly that of harvesting will be mainly that of harvesting the main apple and pear crop, concentrating on preparing fruit for export and for cool storage. Spraying operations' for the season will be practically finished in most districts, with the exception of further applications of a fungicide for the control of black-spot on late varieties of apples should humid conditions be experienced in the late summer. It frequently happens that a late infection of black - spot occurs on Dougherty apples, seriously depleting export quantities. It is advisable, therefore, to continue using lime sulphur 1-180 on this variety throughout March and perhaps into April if heavy rains are being experienced. Red mite may still cause trouble, and consequently a very close watch should be kept on apple-trees so that steps may be taken to prevent a serious attack developing. A heavy attack of red mite may be so damaging as to cause a premature defoliation and fruit dropping before full maturity is reached. Summer oil 1-100 will destroy mite. However, the general experience is that it is difficult to cover a tree so completely with spray as to destroy every mite present. Sufficient numbers may be left after a first spray still to produce a heavy infestation. A second application seven to ten days later will give comparative freedom from further serious infestation, and such procedure is the best to follow. Handling the Export Crop. The main apple and pear crop is harvested over a comparatively short period, and good organization is required at every point to handle the product

successfully and have it shipped in the best possible condition. The necessity for avoiding delay from the time fruit is picked until it is placed in cool storage prior to shipping or delivery straight to the ship cannot be too strongly emphasized. Short delays must inevitably occur at points between the grower’s shed and the final delivery into the store. It therefore becomes imperative that no delay should occur in packing and delivering fruit to the inspection point after it is picked. With such tender varieties as Cox’s Orange, and particularly with pears, the grower should aim at having each day’s picking delivered to the inspection point the following day. Much may be done in the orchard and packing-shed to ensure that the fruit is delivered in the best possible condition for shipping. It is important in the first place to remove at one picking all fruit which has attained Sufficient maturity, irrespective of colour, and have it graded correctly. High colour and higher grading should not be secured at the risk of impairing condition. During hot weather extra care should be exercised by stacking the newly-picked fruit in the shade of the orchard trees while awaiting cartage into the packing-shed. At every point efforts should be made to keep fruit in cool positions, whether awaiting packing or packed, in order that as much heat as possible may be thrown off. Packingsheds should be well ventilated. It is most important in - grading to reject all fruit showing skin injuries, whether through stem-punctures, insect-bites, or other causes, as such injuries are a prolific source of wastage in export fruit through fungal rots developing at the points of injury. Export cases should be kept under cover and preserved in a

clean, dry condition. For the sake of attractiveness of package and get-up cases should not be stacked outside, as they soon take on a weathering and lose their bright, new appearance. Reworking by Budding. Budding is used as a means of reworking stone-fruit trees which do not readily respond to grafting. The whole operation of budding consists of taking a fully - developed wood-bud from a shoot of the current season’s growth and making a T-shaped incision near the base of a new shoot forced from the older tree previously headed down, inserting the bud in the incision, and then binding with raphia. It is important to observe the following points if budding is to be a success. Buds should be selected from the middle portion of a shoot and rather nearer the base than the top. It is necessary to use only wood-buds, and these are distinguishable by being more pointed and thinner than fruit-buds. Treble buds of peaches and nectarines should be selected, as the centre bud is always a wood-bud and should produce a shoot. Shoots from which buds are being secured are prepared by cutting off the lower and upper portion and removing the leaves, but leaving about J in. of the petiole or leaf-stalk. The shoots thus prepared, known as bud-sticks, must be kept fresh. It is advisable to perform the operation as soon as possible after the bud-sticks have been selected. An examination of buds is necessary a month after the operation, and if the growing stock is causing the ties to cut in it is necessary to run a knife through

them at the back of the stock. The cutting-down of the stock to the bud is not done until the end of the winter, and it is not then advisable to do it early enough to force the buds into growth at a time when frosts are sufficiently intense to damage the tender shoots. —N. J. Adamson, District Supervisor, Nelson.

Citrus Notes.

Sowing Down the Cover Crop.

IF the 3 per cent, summer oil has not yet been applied to citrus trees it should be done as soon as possible, as March is the last month of the current season for a thorough application of oil sprays to control scale insects. The pruning of lemon-trees should be carried out before the onset of the colder months. By experience with ' “ bare poled ” trees it has been noted that the best months for pruning are from November to March, and now that the trees are practically clear of heavy crops a suitable opportunity for pruning is provided. At whatever time of the year pruning is done on a lemon-tree some fruit must be sacrificed, but a well-pruned tree will carry a better crop of rub-free fruits. In view of the winds experienced in all citrus districts it is extremely difficult to shelter an orchard adequately. This can be overcome to some extent if the leaders and laterals in a tree are well spaced, the vigorous upright “ sucker ” branches in the centre of the tree removed, and the long, slender, lateral branches cut back to stronger wood which is capable of carrying a crop without its being blown around by every wind or weighed down and swept along the surface of the ground., Adequate Pruning. Too much stress cannot be laid upon the necessity for adequate pruning. If New Zealand grapefruit or sweet-orange trees are inclined to bear small fruit pruning at this time of the year, if not too

drastic, will prove beneficial. Few growers neglect manuring, but many neglect pruning. During the next few weeks citrus orchardists should endeavour to sow down the green manure or cover crop. In young orchards the blue lupin is an extremely useful crop for regular use each winter until the citrus trees come into bearing. This is one of the best soil-bearing crops, and is vital in the young orchard. Sow at the rate of 2 bushels to 2J bushels per acre and 4 cwt. to 5 cwt. superphosphate per acre. In some districts the soil appears to become lupin-sick and it is necessary to turn to some other cover crop. This is also the position when trees begin cropping heavily, as it is difficult to pick the .crops from June to August when a good stand of lupins is in the orchard. It is sound practice to sow alternate lands one year and the bare lands the following year. By this method pickers and implements can work between the trees without adversely affecting the greenmanure crop.. An alternative method is to sow a green-manure crop which does not grow to any height and which is not much affected by the monthly picking operations. Such crops are Austrian winter peas, 1 vetches, red clover, and Lotus angustissimus . The last two are equally suitable as permanent cover crops. When small seed is used it is best to mix it with the superphosphate before broadcasting. Whatever green-manuring crop is chosen, February-March is the period

for sowing down. Sow at approximately the same rate as lupins for the peas, and at io lb. per acre for Lotus augustissimus or red clover. Permanent Sward. Some of the leading citrus-growers, especially on the lighter soils or on slopes, are putting their citrus groves down in permanent sward. This is to be recommended if a leguminous crop is sown down and kept cut during the summer months whenever dry conditions set in during any season. Humus or organic matter is essential to the successful growing of citrus fruits, and the sowing-down of a permanent crop can be safely recommended in established groves, especially when trees are of such a size as to impede cultivation implements. If such cover crop ” be kept cut and the trees mulched the tilth of the soil will be improved. Soil-erosion will be reduced and the nitrogen content in the soil will be built up instead of being depleted. It is well to remember, however, that the above is not a recommendation towards rank weed-growth in an orchard. Weed-growth during the winter months is better than clean cultivation, but weeds generally induce nitrogen starvation in the trees. Whatever method is adopted by a grower, the aim must be the improvement of the tilth of the citrusorchard soils, and this can best be done by a leguminous cover crop in some form or other. —L. Paynter, District Supervisor, Auckland.

Viticulture.

Phylloxera-resistant Stocks.

(Continued from December issue.)

The Solonis. THE Solonis or Novo - Mexicana, according to Viala, -is a natural hybrid Riparia-Candicans. Millardet thinks its origin is more complicated and that Riparia, Candicans, and Rupestris composed its make up. It is found along the banks of the Red River, a tributary of the Mississippi, in the north-west of Texas and in New Mexico in regions belonging to the cretaceous formation. It is also found

in Colorado. Along the Red River it grows in very rich, red, sandy soil-very often wet and always damp. In the Panhandle of Texas, quoting Viala and Pechoutre, the soils in which the Solonis grow vigorously are dark to blackish-red and fine and sandy, with numerous flakes of mica distributed through it. The subsoil is formed of flaked yellow clay. The Solonis under these soil conditions develops a very vigorous growth and thick trunk.

The Solonis played a very important role in the reconstitution of the French vineyards during the first periods of the phylloxera crisis. Its vigorous growth and relative resistance to chlorosis in calcareous soils, combined with its tendency to root and take grafts easily and its affinity for vinefera (European sorts), led to its being adopted in many of the vineyards. ' ' After a time it was found that the Solonis was not sufficiently resistant to

phylloxera in soils very favourable to the propagation of that insect, and in consequence it was gradually abandoned in favour of stocks having more resistance, especially the Solon is x aria, 1616 (Couderc), which is more resistant to phylloxera and accommodates itself, like the Solonis, to wet and brackish conditions. According to. Viala and Pechoutre, the principal ampelographic characteristics of the Solonis are as follows : Vigorous spreading habit, trunk thick ; rods long, smooth, cylindrical, with tufts of whitish hair near the ' nodes, purple in the herbaceous state and light brownish-grey

when lignified ; leaves medium size, entire, two series of acute teeth, a few longer ones indicating the terminals of the lobes ; those of inferior lobes converging towards the axis of the leaf, which forms a gutter with the lower extremity curved downwards ; petiolar sinus shallow and very open ; smooth on both faces, stiff whitish hairs along the veins on the under face, and a few shaggy flakes of fluff on the petiole and the upper face of the leaf, which is greyish-blue, the lower face being somewhat paler. A number of the hybrids bred from the American vines described in this and pre-

ceding issues have been in' use for some years in New Zealand, and others, containing some of the same blood, are being tried out for adaptation, affinity, and resistance. 1 A complete collection of the stocks selected from the early types in the past and those under observation .at the present time exists in the vineyard of the Horticultural Station, Te Kauwhata. These will be described in later issues of the Journal. —J. C. Woodfin, Vine and WineInstructor, T Kauwhata.

Cool Storage Notes.

Handling and Precooling Export Pears.

T XT THEN harvesting this season’s crop WHEN well to keep season’s crop it is well to keep in mind that the maturity of fruit when picked plays a most important part in its postcool storage quality and appearance. At the beginning of the 1939 season no better suggestion could be put forward than that methods for the handling and precooling of export pears be adopted which will definitely prove beneficial by ensuring their arrival on overseas markets in a uniformly sound condition. The method recommended is as follows : < (1) All pears should be placed in cool storage within twenty-four hours of picking and held at a temperature of 30° to 32 0 F. (2) Pears should not be packed for longer than fourteen days prior to loading on the overseas vessel. The present system of handling pears is not satisfactory, as it is very difficult to obtain uniformity of condition in a case of packed pears. The Fruit Inspector is unable to detect a slight tendency toward maturity in the pears at the point of inspection, as, when fruit is delayed after picking for grading and packing, some of

the fruits, by virtue of their position on the tree, &c., are more fully matured than others. It is this fruit that is responsible for much of the deterioration mentioned in reports from overseas markets. The method recommended is designed to lengthen the pear-export season by improving the conditions of handling and precooling export pears prior to loading the overseas vessel. This improved condition will enable the London Manager of the New Zealand Fruit-export Control Board to avoid selling on glutted markets by being able to hold the pears in cool storage overseas, and also to allow for furtherdistribution to more distant European markets. Placing pears in cool storage in orchard boxes immediately after picking and before packing will check maturity, provided the fruit has been harvested in a firm, green, yet matured state. Holding the pears in orchard boxes in cool storage until ten to fourteen days prior to loading the overseas vessel will enable faults in the fruits to develop before packing, and will therefore tend to lengthen the pearexport season, as any bruised or faulty fruit is rejected and only fruit that has been cool stored under good storage conditions and is in the same firm condition as when harvested will be packed for export. The supervision of cool-storage conditions is also necessary to ensure that the systems of cooling and stacking the cases in cool storage and the temperature control are up to the required standard. Cool-storage facilities are required in many districts to enable pears to’ be precooled. In these districts delays in pears

reaching cool storage should not be longer than thirty-six hours after picking. It would be beneficial for the pear producers to organize in each area with a view to adopting improved methods which would fit in with the cool-storage facilities available for the immediate cool storage of all pears intended for export. All export pears handled and packed on the lines mentioned should be labelled " Precooled Pears." . . Apples, such as Cox's Orange, when picked, should be packed as soon as possible and placed in cool storage to check the further maturing of the fruit. When picking pears or apples into orchard boxes for precooling for export or for long holding, newspaper should be used to line the boxes, as it has a tendency to check marking and bruising. Granny Smith apples for long holding should be picked into orchard boxes and held in the orchard for from two to three weeks in a cool, dry position, the stack being well opened up for ventilation. The date of picking should be about the 16th to 20th April, although the date will vary with local seasonal conditions. No fruit should be held out of cool storage after being packed, as deterioration develops from blemishes and other causes more quickly when it is held in the packed case without being cooled. When stacking fruit in cOol-storage chambers allow adequate space for aircirculation, as good ventilation is one of the most important features in obtaining satisfactory results with fruit in cool

storage.

—A. Powell, Cool Storage

Officer, Wellington.