NOT DIFFICULT TO DESTROY

Wairarapa Times-Age, 24 December 1940, Page 2

NOT DIFFICULT TO DESTROY

APHIS, GREEN AND BLACK FLY. The various kinds of aphis which attack carrots, beans, brassicas, and swede turnips are very troublesome, not that they are difficult to destroy, but because they multiply so quickly. They suck the juices out of the plants, cause the leaves to curl up and weaken the plants considerably. In fact, if left unchecked in a season

which suits them, they will destroy the plants altogether. They are destroyed by what is known as a contact spray, one which either blocks up their breathing pores and smothers them or burns them up. A soap solution of any kind is very effective, for it forms a film over them and prevents breathing, but to make doubly sure, a little blaekleaf 40 is added, and it poisons them. Kerosene emulsion is also effective, and so also is derris powder, which has the advantage of being nonpoisonous. Dissolve 4oz of soft soap in four gallons of hot water and add a dessertspoonful of blackleaf 40. Apply while still hot, and be careful to wet the undersides of the leaves as well as the upper. It may be necessary to spray at intervals of a fortnight until the plants are clean. The bean aphis always attacks the young growing tips of the stems, and if these are pinched off and burned, most of the fly is re-t moved. Dusting with derris powder | should destroy any on the older parts of the stem or leaves. The celery fly is also destructive. As soon as the celery is put out the fly appears and lays its eggs on the leaves, and in a short time the grubs are hatched and commence their work of destruction. They cannot be attacked by either sprays or dust at this stage, but by making the plants distasteful and obnoxious to the fly by spraying the plants with tar water or kerosene emulsion, the fly will not lay its eggs. Dusting with soot or among the plants with gas lime is also recommended.

The caterpillars of the white butterfly and the diamond back moth both lay their eggs on the leaves of cabbage, cauliflower, swede turnips, and all other brassicas, and the caterpillars eat up the tissue of the leaves and work into the hearts of cabbages and savoys. The caterpillars can be hand picked or they can be poisoned by spraying the plants with arsenate of lead, but this cannot be done as the plants develop. They can then be sprayed with salt and water or they can be dusted with derris powder.' • The Red Spider is not a spider, but a very small mite which attacks the undersides of the leaves of runner and dwarf beans, and cucumbers, sucking the juice out of them and causes them to look pale and sickly. The pest covers itself with a web-like material hence the name red spider. It is really a dry weather pest, and soon disappears with the autumn rains. “Thrips” is a tiny little black or dark grey insect, and does much damage to late crops of beans and peas. In bad attacks they cause the pods to curl up and stop growing, and soon put an end to the crop. Even when they are not sufficiently abundant to stop growth, they give a rusty effect to the pods and spoil their appearance. They arc so small that it is difficult to detect their presence until there are indications of malformed growth. Spraying with a quassia and soft soap solution of kerosene emulsion is recommended.