THE RURAL WORLD.

King Country Chronicle, Volume V, Issue 370, 17 June 1911, Page 6

THE RURAL WORLD.

THE POTATO MOTH. The following account of the potato moth that has done so much damage this year is from a paper by Mr A. H. Cockayne in the "Journal of the Department of Agriculture" : According to Meyrick the potato moth was probably originally a native of northern Africa, feeding on a variety of plants until, on the introduction of the potato into the Old World, it transferred its attention almost entirely to that crop. At the present time it is in many countries the most serious insect enemy of the potato, not excepting even the famous Colorado beetle—Lepinotarsa decomlineata The potato moth is especially serious in the Mediterranean regions, South Africa, Calfornia, and Australasia. In Tamaania and many parts of the Australian mainland it annually occasions great loss and seriously depreciates the crop, especially after it has been stored. In New Zealand it is now widespread throughout the North Island, and in the South as far as Dunedin. The important potatogrowing areas of Southland are apparently yet free, but it is only a matter of time before the moth will be prevalent as far south as the potato is grown. The lifp-cycle of the insect commences with the depositing of a small glistening egg by the brownish moth on the lower portions of the haulmus, the batiks of the leaves, or the exposed portion of those tubers that are nearest the surface and which may not be entirely covered with earth. Exposed tubers generally have the eye end uncovered, and the eggs are generally deposited in or near the eyes. Each female moth may lay a number of eggs varying from one to two hundred, and the process may be extended over several days. In due course the eggs hatch, and the young larvae bore their way into the tissues. In the case of.leaf infection the larvae eat out the tissue between the two surfaces much after the style of the cineraria-leaf miner—Phytomyz anirgi cornis. In haulm infection the larvae bore down the stem, and, it is said, in this way enter the tubers. So far as the present South Island outbreak is concerned, the majority of tuber infection that has occurred during the growth of the plants has taken place by eggs deposited directly on the tubers. This is evidenced by the fact of the eye end being invariably attacked. This would not occur if the larvae had entered them by way of the stems unless they bored out and entered the soil first, but whether this is a characteristic of the larvae has not been definitely ascertained. When once the larvae have entered the tubers they tunnel galleries in all directions, and when a potato is cut across the whole interior may be found to be riddled. The full-grown larvae are about half an inch in length of a dirty white colour often tinged with a pinkish or greenish hue; the head is dark and in full-grown specimens quite black. They may remain in the tubers for about eight weeks, when they work their way out and seek a suitable place to pupate. They often pupate on depresaiona on the tubers, or on the sides of the sacks, in crevices in the store house,or attach themselves to the straw coverings of the pits. Before undergoing pupation a rudimentary cocoon of dirty-coloured silk is spun, which acts as a shelter to the dormant insect. During the summer, about fourteen days pupation, the moths emerge. They resemble the clothes moth, to which they are closely related. The wing expanse varies from fin to Sin. The forewings are light brown mottled with dark brown or black; the hind wings are narrow, blue-grey in colour,with a deep wide fawn-coloured fringe. There appears to be several broods throughout the year, but in all probability the last brood develops pupae that" remain dormant for several months.especially where the winter is at all severe. The broods overlap on another, and this renders control methods more difficult than if they were well defined.

SHEARING CLASSES. The circular letter from Mr J. G. Wilson, President of the Farmers' Union, relating to the institution of sheep-Bhearing classes is being favourably received in the pastoral districts. Discussing the matter at the monthly meeting of the Hawke's Bay Agricultural and Pastoral Society, the chairman stated that he had gone into the matter when in Christchurch and found that the Sheepowners' Association inaugurated such classes and had got the use of the A. and P. Soiecty's buildings in which to conduct them. Unfortunately the Hawke's Bay Society had no buildings of the kind suitable, and though argeeing with the principle, thought it more a matter for the Sheepowners' Association ihan the Bociety. Personally he would lend his shed for a month if anything came of it. Mr R. Wellwood thought it a capital suggestion, and one which the society Bhould take up.—Mr B. Chambers suggested that the sheepowners be asked to each take one learner in their sheds this season. The President suggested bringing the matter under the notice of the technical authorities and the Sheepowners' Union, and urging them to try and arrange classes.—lt was decided to give effect to the President's suggestion.

GENERALITIES. A Wairarapa dairyman holds that the moisture contained in the New Zealand butter is too great and that in consequence it cannot compete with the Danish article on account of the distance that it has to be shipped. A dry butter, he states, will arrive Home in a better condition than that with a large moisture content. A German patent has been secured for the manufacture from the Soya bean of a product to take the place of rubber. The process consists in the reduction of the oil of the Soya been

to a thick, tough liquid through the addition of nitric acid After further treatment with alkaloid solutions the mixture ia heated to 150deg., giving a tough, highly elastic product similar to rubber, which can be vulcanised by the same process as rubber. "I have been in the district over forty years," said a pioneer colonist to a "Manawatu Standard" reporter, "and there has been no such prolonged absence of rain as occurred last summer since I have known Manawatu. Such might not occur again for another forty years.' An early rise in the price of Btock is predicted by a well known local authority in this district, says the "Manawatu Times," on account of the phenomenal growth of grass which has taken place during the past month or so, the mild rains having again proved how quickly the grass p ickfl up in this district after a drought.