VEGETABLE GARDEN

Timaru Herald, Volume CXLIII, Issue 20890, 20 November 1937, Page 15

VEGETABLE GARDEN

Strawberry pests and diseases The two fungoid diseases which are most prevalent among strawberries are mildew and leaf spot, but both are easily Controlled by sulphur, if it is applied in the early stages of attack. A 3 per cent, lime-sulphur spray will be effective, or the powdered form of flowers of sulphur can be dusted on the plants. Leaf spot confines its attack to the leaves, where it forms round, purplish spots, and does not usually harm the crop, unless it is so widespread as to interfere seriously with the work of the leaves. Mildew can spoil the crop, as it covers the berries with a white powdery deposit, but, as it usually .iljpears first on the foliage, too. clarpagff.to the fruit can be prevented if control measures are taken promptly' on its appearance.

A yellow or rusty appearance of the leaves, which is sometimes mistakenly thought to be a form of fungus, because the agents causing it are too small to be seen, really denotes the presence of red spider, a tiny mite, which congregates In its thousands on the undersides of the leaves, and sucks the sap flfem them. Warm, dry weather

is most favourable to an infestation, and moisture alone is a means of control, while other effective measures are the application o fsulphur compounds, as for mildew. A more serious menace Is an even smaller mite, the Tarsonemid mite, which is so minute, being only l-120th of an inch long, that its presence is often unnoticed until it has Increased to large numbers, and then only by the resulting effect on the plants, strawberry plants which are infested have small, weak and deformed leaves, and in severe cases the crown dries up, and does not develop at all. The mites dislike daylight, and collect in the young unopened leaves round the growing point of the plant, puncturing the tissues to extract the sap. This pest has only been discovered during the last few years, and the best control method known is again limesulphur. It will be evident from what has been said of the habits of the mites that to be effective the spray must be directed with considerable force into the heart of each plant. This wash is fatal to the mites themselves, but does not kill the eggs, and so more than one application may be necessary during the egg-laying period in order to kill mites which have hatched out in the meantime. Eggs are not usually found on the plants during the winter, but are laid from September to March. As lime-sulphur may cause scorching of the leaves during strong sunlight, a dull day, though not a wet one, should be chosen for the spraying operations. Another pest which may be present all the year round on. the plants is the strawberry aphis, which is one of the causes of “small leaf." The best time to take measures against It is in November, when the aphides are feeding on the young leaves, and can be killed by spraying with a nicotine and soft soap solution. As this wash will probably be needed for greenfly on rases now. It will entail very little extra trouble or expense to use it on the strawberry bed at the same time.

These are the most common troubles and diseases, although it is not an exhaustive list of all the possible ones. It is significant that one trouble may lead th another, either directly through the aphides or mites acting as. carriers. or Indirectly by lowering the vitality of the plants, and so predisposing' them to fall victims to the next foe; but it is possible that they may all be avoided by taking certain measures which will lessen the risk of any attack. Preventative Measures The first of these precautions is to propagate only from clean stock, obtaining the young plants from a good

firm, if they are bought, or choosing runners from perfectly healthy plants in one’s own garden. A further safeguard against aphides is to dip the tops of the young strawberries in a nicotine and soft soap solution before planting them. These dipped runners should be then planted out without delay. The second consideration Is to cultivate the plants so well that they are constitutionally strong and healthy, and better able to resist any onslaught by pest or disease. This Involves, beside the routine work of hoeing, strawing, etc., a thorough preparation of the ground before making a strawberry bed by deep digging and manuring, as well as feeding the plants in after years by means of a manurial mulch or artificial fertilisers.

A third wise plan would be to act on the principle that “prevention is better than cure,” and to maintain a regular routine of spraying or dusting, even if the plants appear to be in good health. In autumn all decaying leaves should be removed, as well as those which show signs of disease, such as leaf spot; any unhealthylooking plants should be rogued out, and the bed dusted over with flowers of sulphur. In September a limesulphur spray, at 3 per- cent, strength, will account for mites before the egglaying period begins, and will ensure that the young growth of the plants gets a good start in development, while a nicotine wash in November will check attack by aphis. This is not an elaborate programme, and will probably be sufficient to keep the plants in a healthy state, though it can be extended to meet any particular trouble which becomes noticeable.

To keep the beds clean is part of the routine work which should be done as a matter of course. Hoeing and maintaining clean cultivation, not only in the strawberry bed, but in the adjacent parts of the garden, will lessen the number of slugs and snails, though a few slugs are almost inevitable in wet weather; while the timely adjustment of netting will frustrate the birds’ efforts at obtaining first peck at the fruit.

MARROWS AND PUMPKINS Marrows, pumpkins, and apple cucumbers may now be planted out in frames or sheltered places. The usual practice is to dig out a fairly large hole and fill it with well rotted manure which should be firmly trodden in. During hot weather give a thorough soaking with water and damp the plants overhead in the evening. For the first few nights after planting give a little protection by covering the plants with an upturned flower pot. The bush marrows are most satisfactory for a small garden because they do not require so much room as the spreading varieties. If the fruits are used when quite small the plants are encouraged to produce over a longer period.