THE ORCHARD.

New Zealand Journal of Agriculture, Volume 53, Issue 3, 21 September 1936, Page 178

THE ORCHARD.

Cultivation.

In all localities where soil conditions permit, cultivation should receive special attention, and every effort should be made to reduce the soil to as fine a tilth as possible. There are but few orchards where, without detriment, cultivation can be dispensed with. An important point which must not be lost sight of is that the season’s crop largely depends on the condition in which the soil and trees are kept during the early summer months. * Fertilizers. It is not too late to apply nitrogenous and phosphatic fertilizers, but the application should not be further delayed. Grafting. Grafting should be commenced this month, and in most districts may be continued throughout October, but it is important to remember that to obtain the best results the scions for grafting must be kept in a dormant condition. The buds on the scions should be healthy and plump, and care should be taken that only wood free from disease is used. Spraying. Spraying must not be neglected, otherwise the majority of the fruit crops will be unfit for market. Usually at this time of the year showery weather may be expected, which is favourable for the germination of the spores of all fungous diseases. A close watch must be kept for powdery mildew. Apple and pear trees should be sprayed at petal-fall with lime-sulphur (polysulphide content 15 per, cent.) 1-120. To this may be added 2 lb. of colloidal sulphur per 100 gallons. In addition to controlling powdery mildew, this mixture also controls black-spot on apples and pears, providing the spraying programme as set out in the orchard notes for the last month has been carried out. Where leaf-roller caterpillar is prevalent it will be found advisable to spray apple and pear trees at pink tip with i| lb. arsenate of lead powder to 100 gallons of water. This destroys a large number of the first hatching, and therefore makes it more easy to control throughout the remainder of the season. Quite a number of growers neglect to spray for this pest until the fruit is damaged, and in the majority of cases the grub is then protected by fastening a leaf to the apple, or rolling and fastening the leaves loosely together with silken threads into a nest in which they feed.

For the control of codling moth the trees should be sprayed at petal-fall with arsenate of lead powder, i J lb. to 100 gallons. This may be combined with lime-sulphur, providing that 3 lb. hydrated lime is added to the mixture in order to assist in preventing leaf scorching or damage to fruit. This should be repeated at three-weekly intervals.

For the control of leaf hopper the trees should be sprayed while the hopper is in the nymph stage, with nicotine sulphate 1-800. This should be repeated in from ten to fourteen days. If the nicotine is not combined with lime-sulphur or arsenate of lead, 3 lb. of soft soap should be dissolved and added. Ten days after petal-fall apple and pear trees should be sprayed with lime-sulphur 1-180, plus 2 lb. of colloidal sulphur per 100 gallons, to prevent powdery mildew and black spot. This to be repeated at ten-day intervals. Stone-fruit trees should be inspected carefully for green and black aphis, and immediately either or both of these pests are observed nicotine ■sulphate (1-800 plus 3 lb. soft soap) should be applied, and repeated in from ten to fourteen days.

For the control of brown-rot spray at fruit set with lime-sulphur (1-80 plus 3 lb. colloidal sulphur), to be repeated in three weeks.

-—B. G. Goodwin, Orchard instructor, Christchurch

Citrus-culture.

Disease.— -If weather conditions have been favourable (that is, excessively moist) to the development of citrus brown-rot, those growers who have not applied a good covering of Bordeaux to their trees would be well advised to again spray thoroughly now with the 3-4-50 formula. An application .at this time serves a dual purpose, as apart from being a protection from brown-rot it also serves as a protection to leaves and shoots against infection from verrucosis lesions on mature fruits, leaves, and shoots. Although the main spraying for the control of this disease comes later, the above - mentioned application should not be omitted in groves where verrucosis has been prevalent during the past season. In the use of Bordeaux mixture some growers still adhere to the old formula of 4-4-40, and while in itself there is no harm in this, there is a possibility of uncertainty and confusion arising in the minds of some who see one formula in one publication and a different one in . another. To avoid this, the 3-4-50 formula has been adapted generally as standard for all plants in foliage. The main point for growers to keep in mind is not so much the strength of the mixture but the thoroughness with which it is applied ■combined with correct timing of the application, which all count in securing successful control. Pruning. Now that the danger of frosts is practically over, pruning may be attended to. It is not suggested that the pruning of citrus is a Tegular and extensive task similar to that for deciduous trees, but undoubtedly in many of the older groves there is not sufficient pruning being done. The removal of dead and diseased wood should be undertaken .as a matter of course. Efficient growers do not allow this to accumulate in their trees. Apart from wood injured or killed by frost much of the unthrifty wood is pruned out at picking-time. The cause of many of the ■dead spikes which lead to branch-rubs and scratches is faulty technique by pickers, who often snip' off a lemon close to the button and leave on the tree a weakly stub of wood which ultimately dies ; if this is not removed it is a potential source of damage to maturing fruits. The approved method of picking fruit is to make the first cut back into healthy wood, and then with the second to trim off the twig from the fruit close to the button. But this, however, is mere routine work. Whether a tree requires special .attention by way of a thinning-out of the leaders and a cutting-back of the laterals can be determined only by careful observations made during the course of other orchard operations, particularly picking. For instance, where lemon-trees are not “ sizing up ” their crop at a normal rate and are colouring their fruit before it is large enough for picking, they may need reinvigorating by hard pruning. It may be necessary to use the saw, and to remove some of the main limbs in order to obtain the desired vigour. Just as with trees of other kinds of fruits, many of the citrus trees are

furnished with too many leaders. These are often so crowded together that it is impossible for a good supply of fruiting laterals to develop. Trees, readily fill up the open spaces arising from the thinning out of leaders. Such pruning not only causes the remaining leaders to become stronger, but also is the means of causing a large number of thrifty laterals to be developed, and these in due course should carry heavy crops of good fruit. Planting Trees. — The most suitable time for planting trees must be determined by the individual grower after due consideration' to local conditions. Where it is intended to plant in the early spring, planters should, delay until the danger of frosts and of cold winds is over. It is advisable that late spring planting should be done while the soil is still moist to enable the trees to become established quickly without suffering a set-back due to drought. The distance apart at which the trees should be set is at least 25 ft. for lemons and 20 ft. for oranges on the square system. The holes should be prepared before planting-time. The soil should be worked up finely over a wide area and to a good depth. Some organic matter such as cow-manure, sheep-manure, or blood and bone at the rate of 4 lb. per tree should be worked well down and clear of the soil which is to come into direct contact with the roots. On arrival at the orchard the trees should first be cleared of all packing materials and then “ heeled in ” if planting is not to be proceeded with right away. The roots should not be allowed to become dry. Just prior to planting, the roots should be puddled in mud of a thin consistency and then placed in position in the hole in the proper alignment. The roots should be spread out in a natural position, fine soil should be packed in amongst them by hand in order to separate the roots, and then the remainder of the soil should be spaded in and tramped down, firmly. It may be advisable to water occasionally so that the young trees do not suffer from lack of moisture. In cases where trees have been in nursery rows in the orchard they can be lifted with the soil intact around the roots, transported on a sledge to the holes, and planted without serious injury to the roots or set-back. If the trees arrive in good condition, pruning back of the shoots is unnecessary, but if they suffered in transit a little cutting back and defoliation may be necessary. Where the shape can be improved by a judicious cut or two this may also be done, but it must be borne in mind that with citrus trees one cannot always be sure of getting growth from each and every bud. Little or no pruning should be done to citrus trees until, about the third year, when an attempt should be made to develop an open framework of about five sturdy leaders. Shelter.— Where, in spite of all warnings given to the contrary, trees have been planted out without the provision of adequate shelter-belts, some temporary expedient should be adopted, such as the use of scrim supported by stakes, light brushwood around each tree, or the planting of maize in a couple of rows 6 in. apart. The stalks of the maize remain well into the winter and afford considerable protection. Cultivation. This may now be proceeded with. Underneath the spread of the trees the weeds should be removed and the ground lightly hoed. Care should be taken, particularly when a push hoe is used, to see that no damage is done to the trunk of the tree, as any injury is likely to afford entry to bark-blotch organism. The cultivation of the lands between the trees should be done by plough, discs or rotary hoe, according to the method best suited to the district and the implements available. In a citrus grove the initial spring cultivation is often delayed later than that with other fruits, particularly where the cover crop has been sown late in the summer, in order to avoid the necessity of carrying out the main picking-operations in long growth, which on a dewy morning remains wet for a considerable time after picking is possible. With cultivation, as with other operations, the individual grower must use his judgment. Cultivation of the soil in the early summer, and an occasional harrowing to keep the weeds (moisture.

robbers) down in the hot summer weather, should be the rule. However, as citrus trees, to maintain their vigour, require organic matter or humus, and . excessive cultivation tends to destroy it, this operation should not be overdone, particularly on light sandy soils. Harvesting. The rush of other spring work should not be allowed to interfere with the regular picking schedule. A watch should be kept for fruits which have failed to “ size up ” but have become tree-ripe. These should be removed forthwith.

—A. R. Grainger,

Orchard Instructor, Tauranga