In the Orchard and Vineyard

New Zealand Journal of Agriculture, Volume 66, Issue 1, 15 January 1943, Page 43

In the Orchard and Vineyard

Orchard Notes

Seasonal Work in the Orchard

SOME fruitgrowers make the mistake of finishing their spraying season too early and are confronted with such troubles as late infection of black spot, late codling moth stings, leaf roller damage, and brown rot infection of the maturing fruit.

Stone fruits should be sprayed with lime sulphur 1-200 plus colloidal sulphur (25 per cent.) 4 lb. per 100 gallons to within ten days of harvesting to give added protection against brown rot. Lead arsenate sprays should be continued on apples and pears until January for early varieties and March for late varieties.

Where Bordeaux mixture 1-2-50 is being used on apples as a protection against ripe spot and bitter rot, do not overlook the addition of a spreader such as casein, as mentioned in last month’s notes, to minimise spray blotchiness.

Miscellaneous Work

Every endeavour should be made to raise and plough under some form of green crop each year. Sowing should be done during January. If dry hot weather is experienced at time of sowing, better germination will be secured if the seed is drilled in rather than broadcast and harrowed. When the growing green crop is approximately two to three inches high, the harrows should be run through it to give a final loosening to the surface of the soil. Any budding to be done should be carried out this coming month. Approximately ten days after the budding is completed, the buds should be examined. Where any have died there is still time to do further budding for replacements. Packing Shed and Equipment Before grading and packing operations commence the sizing machine should be thoroughly cleaned, adjusted and tested. Packing benches should be repaired where necessary, and nailing presses be put in good order. A day or two spent on this work before the season commences will obviate many breakdowns, and minor holdups when packing is in progress which cause staffs to be rendered idle. Fruit cases should be made up as soon as possible, and stacked to dry.

Second-hand cases should be cleaned, and repaired. Orchard picking boxes should be repaired and sterilised to rid them of any spores of fungal rots. Fruit cases may be satisfactorily sterilised by dipping and spraying, using any of the following three solutions— Shirlan W.2, 1-15; formalin 1-50; or lime sulphur 1-20. The provision of adequate light in the packing shed, especially over the grading table, is of vital importance to the satisfactory handling of the crop. Overhead light is the ideal as no shadows are thrown, and every effort should be made to provide this system of lighting, even if only for the grading table. High, wide windows are the next best provision. To prevent glare or the heat of the sun striking the fruit the window should receive a coating of whitewash on the inside. Lighting will be considerably improved by whitewashing the interior of the packing shed. If the walls and roof are brushed down, and two coats of whitewash sprayed on, the extent of extra lighting obtained through reflection is surprising. A satisfactory whitewash can be made with strong salty water and sufficient hydrated lime to bring the mixture to a consistency of thin cream. The foregoing recommendation is worthy of the serious attention of

growers whose sheds are poorly lighted. Harvesting Points in the harvesting of pip fruits may be summarised as:— 1. Make at least two pickings. The larger, more mature, and best coloured fruits should be harvested at the first picking, leaving the balance to improve in size, maturity, and colour. 2. Avoid the careless removal of fruits as careless ' picking frequently results in the stalk being pulled from the fruit, or in the pulling of the whole spur. 3. Much bruising of fruit occurs in the picking bag, through being overfull, or being carried partially full by the picker from tree to tree, or up and down picking ladders. If the bag cannot be filled at one or two trees, empty it rather than walk around several trees filling it. 4. Do not overfill the picking boxes. When filled, stack the boxes in the shade of the trees ready for prompt dispatch to the packing shed. ' —R. G. I. HAMILTON, District Supervisor, Horticulture ' Division, Auckland.

Citrus Notes

Plant Nutrition

(Continued.)

Zinc Chemical Symbol: Zn. Occurrence in Nature: Zinc rarely occurs free but in a combined form as the carbonate (calamine) and sulphide (zinc blende). Function: Zinc plays a prophylactic and catalytic role. Plants need loz. available zinc per acre. Most of the zinc in a soil is not available. Recommendations: In the absence of zinc, diseases such as walnut yellow, apple rosette and little leaf of stone fruits occurs. Zinc is probably the

most widespread deficiency of citrus and is known as ‘mottle leaf” in California. The symptoms are a tendency to produce narrow and pointed leaves. In immature leaves, the area between the veins is usually a lighter green in colour. In mild cases of zinc deficiency the symptoms appear on occasional weak twigs and particularly on shoots produced at other than the regular growth period. The remainder of the foliage seems normal. Zinc deficiency is most severe when copper is also deficient and occurs in trees growing on the more alkaline soils, i.e., pH over 6. Zinc deficiency is unlikely to be prevalent in New Zealand citrus soils.

Copper

Chemical Symbol: Cu.

Occurrence in Nature: Copper occurs in the metallic form and also as the oxide, sulphide, and carbonate. Recommendations: Copper also is prophylactic. Very small -quantities of combined copper greatly stimulate plant growth— especially on reclaimed soils such as the Florida everglades. Copper salts, in more than a trace, are toxic to all plants. Its absence results in the twigs turning reddish brown and fruits being similarly discoloured. Copper deficiency is unlikely to occur in New Zealand where copper as bluestone (copper sulphate) is regularly applied with hydrated lime as Bordeaux mixture 3-4-50. Silicon Chemical Symbol: Si. Occurrence in Nature: Silicon does not occur free but as the oxide silica (quartz being free crystalline silica) and combined as numerous mineral —felspars, clays, etc. Recommendations: Silicon causes increased phosphate assimilation. In certain plants the impregnation of the epidermal cell walls with silicon renders them immune from the attacks of fungi and certain animals. Silicon is applied as , a by-product in basic slag which contains 3 per cent, to 13 per cent, silica. Aluminium ' • Chemical Symbol: Al. Occurrence in Nature: Aluminium does not occur free but is present in numerous compounds such as oxides and hydroxides (bauxite). Felspars and clays are complex silicates of aluminium with other bases. Recommendations: Aluminium is present as the aluminium ions in soil solution. Excess of these ions , is a powerful contributing factor to the toxicity of so-called “acid” soils. Aluminium is applied as a by-product in basic slag which contains up to 3.7 per cent, aluminium oxide. Chlorine Chemical Symbol: Cl. Occurrence in Nature: Chlorine occurs only in the combined state, almost entirely as chlorides of such metals as sodium, potassium, magnesium which constitutes the main part of the dissolved matter in sea water. The evaporation of inland seas has lead to the formation of thick beds of these salts,

chiefly rock , salt (sodium chloride), sylvine, carnallite, etc. . ' . Function: Chlorine probably occurs in all plants but apparently is not essential, and exists as ions in the cell sap. Sodium Chemical Symbol: Na. Occurrence in Nature: Sodium occurs in the form of salts which are widespread. They are found in the sea as sodium chloride, in many old salt beds as Chile saltpetre, sodium nitrate, and as a constituent of many rocks and minerals. Function: Sodium is always present in plant ash. It is not considered essential but may replace potassium to a limited extent. Conclusion The first nine elements mentioned in these notes (carbon, hydrogen, oxygen, calcium, nitrogen, phosphorus, potassium, sulphur and magnesium) are major elements essential to citrus trees and can be added in fairly large quantities the transition between beneficial and ■ harmful effects being very

gradual. . With the remaining nine minor elements there is a sharp line of demarcation, : and although the addition of small quantities as a dressing or in a spray , may be beneficial, large quantities may show sudden and serious harmful effects. These elements should therefore be tested with caution on a few trees, and the effects observed compared with untreated similar neighbouring trees. Plant nutrition is closely related to soil fertility and is not a matter simply of abundant supplies of nitrogen, phosphorus and potassium. It consists in the favourable operation of a number of factors and a close study of all of these must be made, especially water conditions. Farmyard manure is the oldest of manures and modern science has not made it obsolete. .It makes the difference between exhaustive and conservative y soil farming. It should not be judged simply by its nitrogen, phosphorus and potassium content. Of equal value is its use in maintaining the organic matter status and hence the structure of the soil and increased biological activity. —A. M. W. GREIG, Citriculturist, Auckland.

Cool Storage Notes

Harvesting of the Pear Crop

AN important factor in the harvesting of pears is the choice of the picking time. Pears should be harvested when fully matured yet firm, carefully handled, and immediately placed in cool storage, in order to ensure that they can be held in the best possible condition up to the point of marketing, and that the ripened product will then be attractive and fully flavoured. When pears are gathered too early the flavour and attractiveness of the fruits in the eyes of the consumer will be seriously affected. When picked too late the maturity of the fruits will be unsatisfactory for their successful cool storage, transportation and marketing. Points to be kept in mind when harvesting: , 1. Pears should be carefully handled to prevent injury from rots which may develop during storage. 2. Avoid any delays after picking and before storage that may occur from (a) shortage of labour; (b) transport difficulties or week-end losses of time after picking and before storage. 3. The attractive presentation of pears on the market free from bruis-

ing and blemishes is of the utmost importance, and has the effect of improving or reducing values accord- . ingly. A method of dealing with pears which provides, for their cooling loose in boxes immediately after harvesting has much to recommend it. The pears are placed in cool storage in a more uniform state of maturity, and held in this condition until required for marketing, when- they are graded, and fruits of similar maturity are packed in the same cases. When stacking cases of pears in coolstorage, they should be so stacked as to provide plenty of air space around the cases, in order that the air circulating in the chambers can quickly remove the heat from the stacked fruit. —A. A. POWELL, Cool Storage Officer, Wellington.

Concrete

has many uses on the farm. Instruction in the mixing of concrete and guidance as to its use is contained in “Concrete on the Farm” (bulletin 184) issue free by the Department of Agriculture.