Spring Work in the Home Orchard

New Zealand Journal of Agriculture, Volume 85, Issue 3, 15 September 1952, Page 219

Spring Work in the Home Orchard

By

H. P. THOMAS,

Horticultural Instructor, Department of Agriculture, Wanganui

SPRING is a busy period in the home orchard. The most important work is that of keeping trees and the developing crops free of diseases and pests, yet it is frequently the most neglected, for few like spraying. Manuring, if not already done, should be carried out without delay so that the crop may secure some benefit from the ■fertiliser applied. Mid-September to early October is the period for grafting, and where this work is contemplated the necessary material should be assembled in readiness. Thinning of the fruit crop is an important job that must not be overlooked where good fruit setting has occurred. Cultivation should be done to keep the soil in good tilth and to control weeds; this is especially important around newly planted trees and will assist them to become established more rapidly. Grapevines, outdoor and under glass, should receive constant attention.

MANY home gardeners have the impression that the fruit crop need not be sprayed until the fruit has begun to grow, and others consider that after applying one or two sprays they have done all that is necessary; disease and pest control unfortunately is not as easy as that. Complaints are often heard that spraying is ineffectual or that a certain spray is useless, whereas the real reason for failure is that the user has insufficient understanding of the principles of disease control. Sprays should be used for the prevention of disease infection and pest attack, not as a cure. The tree and crop should be thoroughly covered by a protective film of spray during the period before diseases and pests are prevalent. Sprays do not give a lasting coverage. Their period of effectiveness is relatively short and may be shortened still more by . continual rains. Further, the rapid growth in spring and early summer soon develops new leaves and increases the size of fruit, so that there are fresh surfaces which are unprotected. Spraying therefore must be continual throughout the season, beginning with the base sprays at bud move-

ment and continuing more or less at 2- to 3-weekly intervals until shortly before harvesting. The three main factors for successful spraying are effective spray equipment, correct spray mixtures, and complete coverage during periods when disease and pest attacks may be expected. Spray recommendations are given in the table on page 221. Manuring Plant foods are removed from the soil each year by fruit trees and bushes, and unless they are replaced by organic materials and fertilisers, the trees eventually must deteriorate in both growth and bearing capacity. The quantities and kinds of fertiliser to use will differ according to the fertility of different soils. Generally it is wise to use a complete fertiliser containing the three elements which are usually shortest; nitrogen, phosphorus, and potash. As a guide the following mixtures (parts by weight) are suggested:— For apples, pears, and apricots: 2 parts of blood and bone, 2 parts of superphosphate, 1 part of sulphate of ammonia, and 1 part of sulphate or muriate of potash. For peaches, plums, citrus, and subtropical fruits: 2 parts of blood and

bone, 1| parts of superphosphate, 1| parts of sulphate of ammonia, and 1 part of sulphate or muriate of potash. The rate of application will vary from lib. up to 151 b. per tree, according to size, age, and cropping capacity. Trees that have lost their vigour and stagnated should receive an increased amount of a nitrogenous fertiliser and potash should be cut down or eliminated for a year or two. Nitrogenous fertilisers should not be applied to trees that are very vigorous and have not settled down to fruiting. As fruit trees take up much of their plant food requirements early in the season, manuring should be done early. If fertilisers have not yet been applied, the work should be done without delay and the manure should be lightly hoed in round the trees. Grafting ’ ' Home gardeners who are contemplating grafting should have the scions heeled in in

readiness for this work. Grafting may be carried out from about mid-Sep-tember, when growth has begun and the sap is flowing freely. If grafting is done too early, the scions may fail to take, and if the work is delayed until the trees have reached the flowering stage, the scions may be “drowned” by the rush of sap and fail to make s a t i s f a ctory growth. Grafting is a convenient m e th o d of

reworking pip fruit trees with a more favoured variety. Gardeners will find pleasure and profit in reworking an unsuitable variety or a seedling. ' Stone fruits and citrus are generally reworked by budding, as grafting is more difficult and less successful. Whatever the method of grafting followed, the essential points are to secure a close contact between the cambiums of scion and stock and to seal the join against air and moisture. A good grafting wax, grafting tape, or green crude petrolatum will give satisfactory seals provided care is taken to cover the cut portions of scion' and stock completely. . Grafts should be watched, and where ties (such as raffia or grafting tape) have been used they should be eased as soon as the swelling of. the scion indicates that it has taken; this can be done by running a knife through them on the side opposite to the graft union.

Gardeners desiring instructions on budding and grafting should consult the Department of Agriculture Bulletin No. 285 , “Grafting of Fruit Trees”. This and other bulletins giving more detailed information about home orchard work are available free from offices of the Department. Thinning > When crops are light thinning is seldom necessary, and when crops are heavy few gardeners can bring themselves to the point of carrying out this necessary task. To many it may seem a shame to pull fruit off, but unless the overloaded tree receives some relief the fruit will tend to be small and not so juicy and full flavoured. Crowded fruits make disease control more difficult and greatly favour the spread of brown rot. Heavy crops of apples and pears should be thinned to leave not more than three fruits in a cluster, and many

clusters should be thinned to singles or twos. Stone fruits should be thinned to twos or singles, mainly singles. Sufficient room should be left between clusters so that they do not touch. The trouble taken to thin adequately will be repaid with large, good-quality fruit which can be harvested with pride. Cultivation Deep cultivation should have been done in the winter. Once the trees have begun to grow cultivation should not be to a depth that will disturb the roots and upset the supply of food to the trees. Light cultivation around the trees should be begun as soon as weather conditions are favourable and continued throughout the season. After wet weather, cultivation can do much to get rid of excess moisture, and in summer it can assist in preVenting loss of moisture. Weed control is important as a means of conserving moisture in dry months and is also of assistance in disease control by eliminating some of the hosts of diseases and pests. Grapevines The growth of vines under glass should receive careful attention. Vines should be lowered, if this has not been done already, and left until growth starts; this assists in obtaining an even “break” of buds along the whole length of the vine. To assist vines to break into growth increased temperature and humidity are desirable in glasshouses at this time of year. During October new vine growths must be attended to and those showing promise of carrying good bunches should be retained and the excess shoots removed. The shoots to be retained should eventually be pinched off at the second leaf past the young bunch of fruit. The young shoots should be trained to fill the spaces between the rods and should be tied carefully to the supporting wires.

Spray Applications for Home Orchards

Time of application , Pre-blossom Petal fall Two weeks after petal fall and every 18 to 21 days until end of February When pests appear about December-January ' a Petal fall Repeat petal-fall spray once a month to within a fortnight of harvesting November Early January (not. lemons) Mid-February

Treatment Apples and Pears i pint of lime sulphur to 4 gallons of water I pint of lime sulphur, IJoz. of lead arsenate powder, and 3oz. of hydrated lime to 4 gallons of water As for petal-fall spray i pint of summer oil to 4 gallons of water Stone Fruit (except Apricots) I pint of lime sulphur and l|oz. of colloidal sulphur to . 4 gallons of water Citrus Bordeaux mixture (4oz. of bluestone and soz. . of hydrated lime to 4 gallons of water) loz. of lead arsenate to 4 gallons of water 1 pint of summer oil and 4/5 fl. oz. (5 teaspoons) of nicotine sulphate to 4 gallons of water

Pest or disease Black spot, powdery mildew, and other fungous diseases This is the first spray for codling moth; also for fungous diseases Codling moth, bronze beetle, leaf-roller caterpillar, and fungous diseases Red mite, scale insects, woolly aphis • Brown rot, shot hole, leaf rust Verrucosis, grey scale, wither tip Leaf-roller caterpillar Scale insects, black aphis