THE POTATO MOTH.

Dominion, Volume 4, Issue 1219, 30 August 1911, Page 8

THE POTATO MOTH.

AN OPTIMISTIC EEPOItT. Writing in the "Journal of the Department of Agriculture," Mr. A. Clarke says:—A study of the potato-moth under the conditions of the recent visitation, especially i;i the dry areas of Central Otngo, points (o the fact that it is probably not (To'inj to b? a source of trouble to potnfo-growers year after yenr, as npparent!)- it is only through tho continued drought that it has orminated. I have found it is in the most light, dry sails where the tulx-rs are most .affected, heavy clay land, where the moisture has been retained, being practically free fi-om the moth. The moth certainly attacks those tubers which btc exposed abeve Ri'ouiw! first: then gradually works downward, la a number of cases I have known the farmer to dig' his crop on finding the exposed tubers affected; bagging tho potatoes; and, in a few'days, whole sacks were found to be- riddbd from top to bottom. . This procedure, obviously, is inadvisable, as it is merely exposing the whole crop to the moth. I would advise the following: Firstly, great care should be taken.in moulding up the soil nico and fine, to allow the mould to knit well along the top of the drills (this tending to hold the moisture); then, as scon as the moth' appears (wTiich will be in exposed tubers first), go carefully over and pick up the whole of those tubers which are showing abovo tho ground. Mould up aeain, and do not lift the main crop until after a fen- nights' early frost, when the. trouble of having the crop destroyed after lifting will have disappeared; "a.nd al?o in any tubers dug which may have beeu ' affected, the grub will be found to bo dead. This was carried out by a grower of upwards of a thousand "sacks, who had only al:out thirty sacks affected. These vrero mostly those picked up and which were <*• possd above ground some time before lifting the. main crop. I examined these, and in'every case on. cutting open the potato found the grub dead offer a light frost or two. I-certainly-think that by lifting the crop in dry weather the, moth does more damage than by leaving it in tl:n soil and endeavouring to keep tha mould damp. Tt should be pointed out (remarks the Government Biologist on the above interesting note) that leaving the crop multig until after a frost is tmly applicable as a preventive of infection in'those districts where the climate is severe. In inany parts of the North Island the moth is liable to be found on the wing almost throughout the year.