In the Orchard and Vineyard

New Zealand Journal of Agriculture, Volume 64, Issue 4, 15 April 1942, Page 274

In the Orchard and Vineyard

Orchard Notes

Late Picking and Autumn Work

WITH the exception . of the later varieties of apples, the harvesting of the fruit crop for the season will be drawing to a close. There will still be a large quantity of Sturmer apples to be picked, and careful handling is necessary to avoid bruising. •, The best plan is to leave the packing for a day or two after picking, when bruises will become visible and can be eliminated when packing. Sturmer apples left on the trees ’to attain, the' proper, maturity for immediate marketing should be closely watched and picked before any traces of “ripe spot” appear. This disease develop? and spreads very rapidly, and; /any fruit showing the slightest signs of this trouble should be disposed of as quickly as possible. Mid-season fruit stored under orchard conditions should be examined periodically and forwarded to the assembly shed before its maturity. is too far advanced. ? More time will now be available for ■ a general clean-up. All rejected fruit should be disposed of by burning or ’burying, and picking cases should be cleaned and repaired and stacked away for next season’s operations. The grading machines should receive a final overhaul, and all parts should be cleaned and oiled, and repairs effected where required. The packing 'shed itself should receive a general ■clean-up, and its surroundings should be made as hygienic as possible.

Stone Fruit Spraying

With some varieties of peaches, two .applications of spray are necessary to control peach leaf-curl, while., with other varieties one application at the bud-movement period in the spring is sufficient. An autumn spray at the leaf-fall period, using Bordeaux mixture at strength 5-4-50, followed by the usual spring application at the same, strength, should effectively cope with the disease. A spray at this time of the year will also act as a good clean-up for the, season and assist in controlling other fungus diseases that may be found in the orchard. When spraying is finished for the season the outfit should be thoroughly cleaned, necessary repairs effected, and everything left in good order for spring.

Autumn Ploughing Autumn ploughing has many advantages over spring ploughing, and this practice is recommended wherever possible. Ploughing may be done to a greater depth during the autumn than is advisable in the spring, although the ploughing should not be so deep as to injure the roots. The depth will largely depend on the nature of the soil and whether the trees are deep or shallow-rooted. In orchards where surface water is liable to collect during the winter, it is advisable to plough up to the trees, leaving the open furrow in the centre of the rows for drainage purposes. Manuring The three essentials in manuring are nitrogen, phosphoric acid, and potassium, to be used as a complete manure or singly according to the soil requirements. Applications of phosphoric acid in the form of superphosphate and- potassium in the form of sulphate of potash give best results when applied during the autumn season and" turned under when ploughing. Nitrogenous manures may be left un-

til growth starts in the spring, when two applications should be made, one in September and one in November. Generally speaking, for complete manuring the 2-1-J formula of phosphoric acid, nitrogen, and potash will be found satisfactory. As a general manure blood and bone at the rate of 3 to 4 cwt. per acre with additions of potash should give good results. Drainage Autumn is the best time of the year to attend to the drainage system in the orchard. Open drains should be cleaned out, and covered drains examined to see that the flow of excess water from the orchard is being maintained. New lateral drains, where required, . should be dug. Shelter Belts Where the shelter trees have become too high, more especially surrounding comparatively small areas of orchard, resulting in the exclusion of light and air and causing poor growth and cropping, particularly in the fruit trees situated adjacent to the belts, the judicious topping of the shelter belts will be an advantage. If roots of the shelter trees are encroaching too far into the orchard, a trench should be dug alongside to prevent further extension. —G. STRATFORD, District Supervisor, Dunedin.

Citrus Notes

Spraying to Prevent Infection

DURING late April and May measures should be taken for the prevention of an infection of citrus brown-rot. All citrus trees should be thoroughly sprayed with Bordeaux mixture 3-4-50, giving particular attention to the foliage and stems within three to four feet of ground level, and a cover crop should be sown under the spread of the branches. Where this disease has previously been severe and a cover crop has not been sown, prune the trees to allow 3 feet clearance between the lower branches and the ground and stir the soil frequently. This pruning, however, should not be overdone, as much of the best citrus fruit is grown near ground level.

Citrus brown-rot, Phytopthora citrophthora, is a soil .. fungus which reaches the reproductive stage under conditions of excess soil moisture which are common in July or August. The spore, which is capable of developing into a new fungous plant, is splashed by rain on to leaf, stem, oi fruit. Following infection, the leaf turns brown and wilts, the stem shows small, dead areas on laterals, and the fruit turns a, greyish brown, decays, and emits a pungent smell. As prevention is the soundest practice for control of citrus brown-rot, apply an autumn Bordeaux mixture spray at the recommended strength of 3-4-50. If infection appears later, remove all

visibly infected material and burn or bury deeply. To prevent picking cases becoming infected with citrus brown-rot, they should not be allowed to lie-in the orchard during rainy weather. On return from the lemon assembly depots, cases should be scraped, dipped into a solution of Shirlan W.S., 1 part in 1000 parts water, and then stacked under cover. When picking, every care should be taken to prevent infected fruits being placed in the same cases as sound fruits. Besides controlling citrus brownrot, the application of Bordeaux mixture 3-4-50 in the autumn will assist in the control of verrucosis, melanose, grey-scab, wither-tip, and citrus blast. Wither-tip is often better known by its scientific name Glomerella. It is a fungous disease causing irregular dead spots on the leaves, a dying back of the stems, and premature shedding as well as brown, depressed spots on the fruit. This fungus attacks unthrifty trees, and is often observed in spring on ripening New Zealand grapefruit. In conjunction with the spray recommended, remove and burn all dead and weak growth. Citrus-blast is a bacterial disease most active in exposed orchards in late winter and early spring. Infection follows injury by thorns, hail, and frost, lemons being more affected

than oranges. Citrus-blast causes firm, black, circular pits on the fruit, as well a a blackening of punctured aves and twigs ‘ T ° check . ctrus : ’■ bla . remove and burn infected material, provide adequate shelter, and bardan off a^. umn growth by reGaining from adding quick-acting or excessive quantities of nitrogenous manures at this season In addition, an autumn spray of Bordeaux mixture 3-4-50 must be used ■A - scale insect which is becoming increasingly common on citrus trees as well as on several other hosts, especially puriri is the hard-ivax scale Ceroplastes sinesis, fomerly known as the w hite-wax ■ scale. The hard-wax scale secretes honey dew, and an in-

tested citrus tree soon becomes coated with the sooty-mould-fungus, Capnodium citricolum, which, grows on this honey dew. During A P rd and May the young scales are small and star-shaped, and appear on the upper surface of the leaves, especially on the mam and side veins, and in that stage are most vulnerable For control spray with a certified summer oil-l part summer oil to 33 parts of . water or n in small quantities,l pint oil in 4 gallons water. Once the scales have grown and infest the stems and. small branches, they are much more difficult control because of their waxy covering. A. M. W. GREIG, Citriculturist, Auckland.

i c KI C,()0l NOtCS 2

Holding Pears for Marketing

PEARS should now be carefully stacked in cool storage, and should receive special attention until required for marketing. The flesh temperature of pears should be maintained at 31deg. F. and the temperature of the storage atmosphere should not be permitted to rise above 33deg. F. between the time the refrigerating machinery is shut down and the time it is restarted. If the pears have been picked and placed in cool storage at the correct maturity, these temperatures will check i.” the respiration of the fruit sufficiently ( to ensure that it may be held during the remainder of the season in a firm and green condition. The relative humidity of the storage atmosphere for holding all varieties of pears should be maintained at 90 per cent, in order to minimise wilting of the fruits, particularly during long period storage. In order to obtain the maximum refrigeration from cool storage plants during peak periods of the season, the following points may be found useful:— (a) Make sure that the refrigerating plant is fully charged with ammonia. - (b) Remove oil, air, ■ and foreign gases from the ammonia system at regular intervals.

(c) Examine and clean oil and scale traps occasionally. (d) Check ammonia gauges for accuracy. : (e) Examine the distribution of the ammonia . condenser circulating water, and record the temperature of the water in the daily log. (f) Defrost cooling pipes regularly when this is necessary, as a ring of ice on the piping will reduce the cooling efficiency of the plant. (g) Keep the ammonia compressor gland packing in good condition, and renew the packing when necessary to avoid loss of ammonia, as a small leak will soon lose a considerable amount. (h) When calcium chloride solution is used as a brine spray over the cooling pipes, the solution should be constantly maintained at the . correct specific gravity for the brine temperature required. , A daily record of . all the details of the running of the refrigerating plant, chamber temperatures, and relative humidity should be methodically attended to each day and entered in a previously prepared daily log sheet.

A. A. POWELL,

Cool Storage

Officer, Wellington.