CARE OF THE ORCHARD

Wanganui Chronicle, Volume 80, Issue 245, 15 October 1937, Page 5

CARE OF THE ORCHARD

SEASONAL SPRAYING (By J. W. Whelan, Orchard Instructor, Department of Agriculture, Palmerston North. The spray schedule outlined in the August and September notes should be faithfully carried out in every detail so as to ensure control of orchard pests and diseases. The need of applying the correct mixture at the correct time, or stage of growth cannot be over-stressed. Each orchardist would do well to keep a record of the date of the stages of growth of the various trees in his orchard, say from bud movement to fruit set. Such a record will prove invaluable from a control point of view, as it will enable him to anticipate his requirements for subsequent spray applications. It will aiso act as a guide when purchasing spray materials. With the advance of spring each year, Nature arouses from their winter sleep, or coma state, the insect pests and fungi spores. The first sign of this activity takes place about bud movement, and should be guarded against by applying a suitable spray application to the trees in anticipation of an attack not waiting for visible signs of infection, as is often the case.

Perhaps the most dangerous period from infection so far as black-spot, powdery-mildew, brown-rot and leaf curl are concerned is from pre-pink to shortly after fruit set. This is also a dangerous period as regards the first attack of insect pests on the tree parts, for it is between the abovementioned stages of growth that redmite, leaf-roller caterpillar, apple leaf hopper, codling-moth, pear-slug, and scale insects become active, while about the end of October or early November bronze beetle may be expected to appear. Many of the above, both, fungi spores and insect pests, are incubated in the ground from where they subsequently emerge. It must not be' supposed that danger from attack of fungi and insect pests ends with the setting of fruit. Such is not the case; the onslaught of these pests and diseases is continuous throughout the growing season, in fact under certain circumstances there is a danger of black-spot and brown-rot infection after the fruit has been harvested. Fungi are plants devoid of chlorophyll (the green colouring matter present in nearly all plants) and the absence of chlorophyll is one of the principal features by which they are characterised. Black-spot, powd-ery-mildew, leaf-curl, and brown rot etc., are all included in the fungi group, and may be controlled by the application at set intervals of a fungicidal spray, i.e., bordeaux mixture during the early stages of growth, followed by lime-sulphur from bud movement onwards.

Insect pests are of two kinds — biting and sucking. Biting insects are provided with mouthpieces or jaws. They obtain their food by eating certain parts of the host plant, i.e. leaves and fruit. Codling-moth, pearslug, and leaf-roller caterpillar are included in this group. To control these pests a poisonous spray such as lead-arsenate should be applied just prior to their appearance, and continued at intervals as outlined in the spray schedule throughout the growing season until a few days prior to picking.

Sucking insects, i.e. red-mite, scales and aphides are provided with a probocis or trunk by which they feed, sucking the juices from the plant and fruit. Their control consists of a contact spray, i.e., red-spraying oil during the dormant season, and white spraying oil while growth is active. The combination spray recommended for application at petal fall (75 per cent) if faithfully mixed and applied will provide sufficient protection against fungi and eating insects for about 10 days. This spray, however, must be repeated in 10 days’ time and thereafter continued every 14 to 18 days up to mid-December, after which date the lime-sulphur dilution should be reduced as recommended. Stone Fruits

All stone fruits will be well forward by this time, therefore there is little or no danger from leaf-curl or bladder-plum infection, but it is essential that the tree parts be kept well protected from brown-rot, shothole fungus, and leaf-rust infection. For the control of such continue with

the combination spray, i.e., lime-sul-phur, IS fluid ounces, plus colloidal sulphur la ounces, water 4 gallons at intervals of 18 to 21 days unti* about five weeks prior to anticipated picking. Cultivation It is presumed that thorough cultivation has been carried out and the soil reduced to a fine tilth. This being so, the harrows, rake or cultivator should be kept in constant use, with a view to conserving the moisture, and keeping weeds down, etc., thus making available special plant nourishment necessary for the development of fruit and healthy growth.