Home Orchard in Summer

New Zealand Journal of Agriculture, Volume 89, Issue 5, 15 November 1954, Page 467

Home Orchard in Summer

THE home orchardist looks forward to summer, as then he hopes to see in a good crop of clean fruit the results of his efforts during the year. To be a successful grower of high-quality fruit he must attend to all aspects of fruit culture. During the growing season the most important job is spraying for control of pests and diseases, but other aspects, particularly care of young trees and cultivation, must also receive attention, and here N. B. Congdon, Horticultural Instructor, Department of Agriculture, Hastings, advises on correct methods for these important aspects of orchard management.

TOO often one sees in a home orchard trees which have been allowed to crop too soon. A grower’s enthusiasm to take fruit from a young tree before it has reached a satisfactory age usually results in a stunted or lopsided tree incapable of carrying heavy crops. Stone fruit and pip fruit trees particularly require attention in this respect. Some varieties, if allowed to do so, will begin cropping at a very early age to the detriment of growth and tree vigour. During the first few years of its life a tree should be allowed to crop only to the extent that growth and development of the framework of the tree are not impaired. The following is a guide as to the age from planting .at which trees should be allowed to begin full cropping: —■ Years Peaches, nectarines, and plums .. .. . . . . 4 Citrus and apricots . . . . 5 Apples and quinces . . . . 6 Pears . . . . . . . . 7 To . prevent young trees from bearing, blossoms should be rubbed off during the flowering period or fruitlets removed after they have set.

Watering

The effects of drought conditions during summer are aggravated by a light soil, which will require more watering than heavier soils. Young trees, being not as deep rooted as fully grown trees, will react to dry conditions much earlier and will require more frequent waterings. Both with young and older trees irrigation should begin at the first signs of drought. Trees should never be allowed to become obviously wilted before water is applied, as a severe check may result, and in bearing trees the crop may be seriously affected. During dry periods water should be applied often and evenly over the ground, care being taken that the soil is saturated. Wetting the top few inches is useless. Citrus trees require more water than other fruit trees, particularly when they are growing on a lawn and are competing with grass for moisture. Water should be applied to citrus trees well out from the trunk to ensure that the entire root zone is supplied.

Cultivation Young trees particularly should never be subjected to competition from summer weed growth for long periods. Cultivation of these as well as bearing trees should be in the form of frequent shallow cultivation, deep enough to remove weeds but not deep enough to injure surface-feeding roots of the trees. If the area is sown down with grass, a circle or square at least 6ft. across should be cultivated beneath each tree. Mulching of fruit trees is excellent, since it serves several purposes:— 1. By preventing evaporation from the surface it helps to retain soil moisture. 2. It helps to suppress weed growth. 3. The mulch breaks down into humus, which improves soil conditions, makes food material more readily available, and thus helps to build a healthy, vigorous tree. Lawn clippings, old hay, or vegetable refuse are quite suitable for mulching and should be spread round trees after the soil has been well worked up in spring. The mulch can be continually added to during summer. When turned in in autumn it will prove of great benefit in helping to build up soil fertility. Care must be taken to ensure that the mulch is away from trunks, particu-

larly of citrus trees, owing to the risk of infection by the collar rot fungus. Staking and Shelter The home orchardist is not always able to choose the most suitable site for his trees. They are therefore often subjected to unfavourable conditions at certain periods of the year. Normally young fruit trees should not require staking after planting out, except where they may be subjected to strong winds. However, those trees which have weak or shallow root systems will require support at least until they become well established, and some may require a permanent support.' This would apply particularly to apple trees propagated on East Mailing IX (dwarf) stock and to tree tomatoes grown as seedlings. Stakes should be driven well into the ground on the windward side of the tree and a soft, strong material used for tying the trunk to the stake. Ties should be left loose enough to allow normal growth and should be checked occasionally to make sure they do not become too tight. Good shelter is important for all fruit trees during the growing season. Wind damage to fruit and foliage can nullify all efforts to produce good fruit. Citrus and most sub-tropical fruits need shelter more than most

other kinds of fruit. When a home orchard is being established the aim should be to have a permanent hedge Bft. to 10ft. high on the windward side of the section to protect the trees when they are fully grown. While the permanent shelter is growing it may be necessary to provide temporary protection for the young trees by using scrim or hessian screens supported on a wooden framework.

Propping of heavily laden branches may be necessary later in the season as the fruit is approaching the harvesting stage. Breaking of main limbs can be avoided by using forked props at suitable intervals around the trees.

Spraying ' The article “Home Orchard in Spring” in the August 1954 issue of the “Journal” gave information on spraying and important points about the application of sprays. The same article dealt with the aims and practice of fruit thinning.

The home orchardist may apply to the nearest Horticultural Instructor for detailed spray programmes covering the whole season. Here reference is made to the main diseases and pests attacking various fruit trees from November onward and the measures generally adopted for their control. Peaches, nectarines, plums, and cherries: Brown rot, leaf-roller caterpillar, and pear slug (a chewing insect found on plum, cherry, and pear foliage) are the main troubles. To control brown rot spray with lime sulphur (3 fl. oz. to 4 gallons of water) plus colloidal sulphur (ljoz. to 4 gallons of water) at 14-day intervals until about 1 week before picking. From this month onward for control of insect pests add to this sulphur mixture three times during the season D.D.D. (l|oz. of the 25 per cent, material to 4 gallons of water) or basic lead arsenate at foz. to 4 gallons of

water. Either of these should control the insect pests mentioned, but D.D.D. or lead arsenate should not be applied later than 1 month before harvesting owing to possible residue remaining on the fruit. At the first appearance of aphis on young foliage add to any of the above sprays lindane (25 per cent.) at joz. to 4 gallons of water. Lindane should be used only in the early part of the season, as if it is applied later than

5 or 6 weeks before harvesting, it may cause tainting of fruit. Apricots: As apricots are intolerant of sulphur sprays, brown rot control in them depends largely on sprays applied during the flowering period. However, new materials are now becoming available for brown rot control in the growing season. Thiram, if available to home orchardists, is recommended at |oz. of the 95 per cent, material, to 4 gallons of water. Apples and pears: Black spot and codling moth are the main troubles affecting apples and pears. The lime sulphur plus colloidal sulphur mixture specified for stone fruit and applied at the same intervals is recommended for the control of black spot on apples. For black spot on pears Bordeaux mixture (IJ-oz. of bluestone plus 2|oz. of hydrated lime to 4 gallons of water) gives better control. Varieties of pears susceptible to russet (such as Winter Cole) should be given the same sprays as. apples. Copper oxychloride materials such as “Cuprox”, “Cuprokylt”, and “Oxycop” may be substituted for Bordeaux mixture on pears and should be effective at joz. to 4 gallons of water. To any of the above materials (D.D.T. 50 per cent, wettable powder) at joz. to 4 gallons of water may be added for codling moth control. Lead arsenate at l|oz. plus hydrated lime at 3oz. to 4 gallons of water may be used instead of D.D.T., but not later than December owing to possible toxic residues remaining on the fruit. If D.D.T. is to be used throughout the season, D.D.D. (25 per cent.) at l|oz. to 4 gallons of water should replace the D.D.T. some time during November and again in January to control leaf-roller caterpillar as well as codling moth. ■ Codling moth sprays should not be applied later than 3 weeks before harvesting.

Berry fruits: This month and again after the fruit has been picked spray with Bordeaux mixture (4oz. of bluestone and soz. of hydrated lime to 4 gallons of water). Lead arsenate at l|oz. may be added. These applications should control fungous and insect troubles during summer. The next spray for strawberries should be the Bordeaux spray described applied post-harvest 'to control leaf spot. Maturing fruit should not be sprayed.

Grapes: When shoots are 4in. to 6in. long a spray mixture of 3oz. of copper oxychloride, 2oz. of colloidal sulphur paste, and loz. of 50 per cent, wettable D.D.T. powder to 4 gallons of water should be applied to control fungous diseases and insect pests during the growing season. This spray should be repeated just before flowering, when the fruit has set, and again when the berries are about half developed, after which further spraying is not usually necessary. Do not spray during the flowering period, as this may interfere with the setting of the berries. After fruit is half grown dusting with flowers of sulphur will control powdery mildew, which is then the main trouble. Dusts should be applied during still, hot weather for best results. Six dustings during the season should be sufficient if the dust is applied thoroughly to all foliage and fruit.

Citrus fruits: This month spray with Bordeaux mixture at the strength recommended for berry fruits to control fungous diseases such as citrus verrucosis. Add lead arsenate powder, loz. to 4 gallons of water, for the control of leaf-roller caterpillar. This application should be repeated in early January if necessary. To control scale insects on citrus trees spray with summer oil at 1 pint to 4 gallons of water in early February and again about a month later. Should aphis appear at any time from now on nicotine sulphate (5 teaspoons to 4 gallons of water) may be added to any of the above sprays. If used alone, nicotine sulphate should be activated by adding a little soft soap to the water to form a lather. ,

Fortunately there are few pests and diseases which are at present troublesome on sub-tropical fruits other than citrus.

Tree tomatoes: Powdery mildew is the most common tree tomato disease. It causes greyish white patches on the stalks and undersides of leaves. If the disease is unchecked, widespread infection may cause severe defoliation.

This disease can be readily controlled by spraying with lime sulphur at | pint to 4 gallons of water. Applications should begin in spring at the first sign of infection and be repeated at 3-weekly to 4-weekly intervals until control is secured.

Virus infection is common in tree tomatoes, but usually does not seriously affect the cropping. There is no known control for virus diseases. If infection is severe, the trees should be destroyed.

Chinese gooseberries: The leafroller caterpillar is one of the few insect pests attacking the Chinese gooseberry and it can cause considerable damage to the fruit if spraying is neglected. The caterpillars can be

controlled by spraying vines with arsenate of lead (loz. to 4 gallons of water) or D.D.T. (IJoz. of 25 per cent. wettable powder to 4 gallons of water). Spraying should be started about the end of December and continued at 3-weekly intervals until February as necessary. Passion fruit: Brown spot and grease spot are the two most common diseases which attack passion fruit. Brown spot (a fungous disease) is generally apparent in February and Marchgrease spot (a bacterial disease) is more noticeable in winter. Both diseases affect leaves, fruit, and laterals, and cause defoliation, shrivelting and dropping of fruits, and ultimately the death of the vine Pruning in spring followed by thorough application of Bordeaux mixture 3 : 4 : 50 (4oz. of bluestone and s|oz of hydrated lime to 4 gallons of water) at monthly intervals throughout the year safeguards the vines and checks the spread of these diseases. „ i x ap-p £omplete coverg trpc! °j Auit cannot be and S p+ eda ? Spray thoroughly and at the correct time. The above recommended intervals between sprays do not apply during wet weather. Sprays should be more frequent during unsettled weather, and trees should be resprayed soon after heavy rain, especially if the spray has not had time to dry.

Summer Pruning Jummer rrunm 9 Elimination of wood during the growing season is recommended only in special circumstances. Young trees and grafted trees should have unwanted growth removed at this time of the year to throw as much vigour as possible into the main framework, There are times when a fruit tree becomes over-vigorous and removal of foliage by summer pruning may help to reduce this excess vigour and encourage cropping. Where old stone fruit trees are being headed back to reinvigorate them this should be done during the summer, as infection of big cuts by silver leaf spores (Stereum purpureum) is less likely at this time. Half the tree should be cut back this summer and the other half next summer. Wounds should be protected by a bituminous paint, « ’ , • , „ „,. , ~ t. A certain amount of foliage should be removed from grape vines during the development of the berries. Tips o growing shoots should be broken o ff after the fruit has set so that increased energy will go into fruit develonment Qirmmor nrnnina sboiilri development. Summer pruning should never be to ° drastic, as it has a weakenm S effect on the vine. When the fruit begins to colour, any overhanghag leaves should be removed to expose the bunches to sunlight and to promote ripening.

Autumn Management of Paspalum Pastures

UNDER good management paspalum (.Paspalum dilatatum) will live in association with ryegrass and white clover and will produce a large bulk of feed during summer and autumn. Because of this paspalum is considered a valuable constituent of pastures in the warmer districts of the Auckland Province. At the Northern Wairoa Demonstration Farm, Dargaville, production measurements have been taken for the past 5 years from a sward which is dominantly paspalum in summer and autumn and dominantly ryegrass in winter and spring, with much white clover and Yorkshire fog. The production of dry matter of pasture herbage from this pasture has been as follows: Yield of dry Year (I June matter of to 31 May) pasture herbage (lb. per acre) 1949-50 11,220 1950-51 13,330 1951-52 .. ... .. 16,130 1952-53 19,030 1953-54 18,290 The yield in the 1952-53 season of 19,0301 b. of dry matter is the highest yearly production secured to date in Extension Division trials. The trials are located on high-producing pastures throughout New Zealand. The figures show convincingly that a wellmanaged paspalum-ryegrass sward is capable of producing, on good land, herbage yields equal to or better than those of most other types of high-class swards in this country. However, when it is permitted to get out of hand and grow tall and rank paspalum will smother out other grasses and the clovers, and a paspalum-dominant sward which is dormant for 6 months of the year

—C. M. BLICK,

results. Such a pasture suffers from a nitrogen deficiency because of the lack of clovers and soon becomes sodbound. Paspalum in the young leafy stage is comparable in feeding value to other summer grown pasture, but as paspalum reaches maturity the feeding value quickly falls off until it reaches the stalky stage, when it is little better than straw. By good management paspalum can be kept in the young leafy stage throughout summer and autumn. All grazing should be . controlled by use of the electric fence and after each grazing pastures should be topped with the mower to remove seed heads and mature growth. In good seasons, when there is a surplus of feed in autumn, leafy paspalum can be converted into high-quality silage. Sodbound paspalum pastures can be readily improved by correct topdressing in conjunction with good pasture management methods. The introduction of ryegrass and white clover by oversowing after a severe harrowing or discing will sometimes be necessary to hasten results. In good pastures the ryegrass is dominant during winter and spring and then paspalum takes over as the weather becomes warm in late spring, summer, and autumn. At no time does the paspalum hinder the growth of ryegrass provided that it is not allowed to become too rank in autumn. "

Fields Instructor, Department of Agriculture, Warkworth