A DESTRUCTIVE PEST.

Manawatu Standard, Volume LII, Issue 52, 1 February 1932, Page 6

A DESTRUCTIVE PEST.

The appearance in the Hawke’s Bay district of the destructive pest known as the white butterfly indicates the difficulty of keeping New Zealand free from pests unknown to exist here. It is presumed that the butterfly; came from Hawaii, having apparently been loaded there among vegetables bought by q trading ship. Its presence was noted in parts of Hawke’s Bay in 1930, and since then it has appeared elsewhere, as far away as Rotorua and Tauranga. Palmerston North and the wide district of the Manawatu do not appear to have been troubled as yet, but the Director of Horticulture stated recently that the butterfly is spreading rapidly from Hawke’s Bay, so that the period of immunity here may be determined by the progress it makes, or the success of a campaign 'to eradicate it. The fact that the' insect has widely migrated • from the place where it first became established suggests that, were steps not taken to control it, this district could not lolig remain immune from its ravages.' The Department, however, is alive to the menace, and has imported in the cocoon stage a wasp stated to have been an effective enemy of the butterfly in the United States. When hatched, the wasps will be liberated to declare war upon a pest which has proved most destructive to farmers and market gardeners. Rape, lettuce, cauliflower ' and cabbage crops are menaced _ wherever it appears, and considerable destruction has taken place in Hawke’s Bay. The insect can be .controlled, it is stated, by the use of arsenical sprays, and while this is possible in smaller gardens, the cost probably would be prohibitive where cultivation for city markets is undertaken extensively, while for farmers’ crops of rape this method is not feasible. Control or eradication of the butterfly, therefore, must be looked for from another source, and keen expectation will be displayed in the success of the introduced wasp, which, it is hqped, will also' attack another destructive agency in the diamond backed moth. For the wasp itself, it is claimed that if will not prove destructive to plant life of value. The appearance in the Bainesse district of a plant known as “prickly lettuce” is engaging the attention of farmers, and efforts to have it declared a noxious week are being made. It is presumed also to have come from overseas —in horse fodder from Australia. Believed to ( have caused the death of certain stock, it is recognised as harmful because of an irritant juice it possesses, As it seeds _ freely and can spread over a wide area, its control becomes the duty of those in authority.