LOSS OF PASTURES

Evening Post, Volume CXXVIII, Issue 46, 23 August 1939, Page 4

LOSS OF PASTURES

GRASS GRUB AND CATERPILLAR

COMBATING THE PESTS

(By Telegraph—Press Association. 1 DUNEDIN, This' Day. Dr. D. filler, Assistant Director of the Cawthron Institute and Director of the Division of Entomology of the Research Department at" Nelson, who is at present in Dunedin in the course of his survey of grass grub arid' .grass' caterpillar problems in Canterbury and Otago, made the following statement concerning his work last night:— "The Government .and the Cawthron Institute are fully awake to the importance of the grass grub and grass caterpillar problem, and my southern visit is a preliminary to a conference with the Director-General.of Agriculture and the acting secretary of the Research Department in Wellington on Thursday next. ' ..'"-'• "I consider that, grass grubs and grass caterpillars constitute wliat canbe looked upon as the major, entomological problem of this country, since the foundations of our. primary industries, that is, pastures in relation to. meat and wool, are in jeopardy in that many thousands of acres: of pasture land (at least 80,000 in the Ashburton County alone) have been reduced to so much rubbish by these two insects this season, and most especially- at a critical period of the year. By-this I do not wish to belittle in the -least lthe almost equal influence .of the diamond-back moth and the white butterfly upon crops supplementary to the fattening of sheep. . The- latter .insect, through the outstanding work of Mr. J. Muggeridge, is under control from the farmers' point of view, while Mr. Muggeridge's current researches hold considerable hope of the former being eventually subjugated. "The grass'grub and grass caterpillar problems are not for the entomologist alone. They involve many factors, beyond his province,, arid constitute one that demands team work. The fields staff of the Department of Agriculture, the staff of the Grasslands Division of the Plant Research Bureau, the field staff of the fertiliser indus-" tries, and the staff of those concerned with irrigation where that is being developed I find are deeply interested in the matter. From data at- present available I think that control, .-or, at least, a sufficient measure of relief to the unfortunate farmer..,will'be found eventually in a practicable modification of farm establishment of suitable parasites. NATIVE TO NEW ZEALAND. "Both grass grubs and grass caterpillars are insects .native to New Ze» land. Consequently one looks first to what parasites attack these insects in this country, and finding none .looks overseas to. regions where similar peste occur. With grass grubs we find that they have a free hand in New Zealand in that they are in no way subjugated Iby any insect parasite. In the case |of grass, caterpillars we. find one or ! two native parasites which obviously have but little controlling' influence. In looking further afield we find that certain channels of profitable inquiry open up—in the United States, Tasmania, Chile, and the Patagonian region. In Tasmania there exist similar grass grub, insects arid- a population of parasitic forms .unknown^, in.-.New Zealand,.wriich. prey upon grass,grubs. fOur grass caterpillar is a somewhat similar insect to the'grass caterpillar that occurs' in Tasmania, and like the caterpillar in New, Zealand, the Tasmanian one has a natural paras.ite that is ineffective. Indeed, we have ssnt our parasites to the Commonwealth, but, I fear; with little effect. I•• have had word, however, from Dr. J. Evans, Tasmanian Government Entomologist, tli at he expects to visit New Zealand in November to discuss several insect problems of interest to both countries. In Chile arid Patagonia one finds both grass grubs and grass caterpillars similar to those of New Zealand.- During my expeditions to South America I naturally gave some attention to the subjects and found that parasites exist there. Otherwise being engaged at the time, however, I was not able to devote detailed attention to a study of the problem, but nevertheless secured sufficient data to show the possibilities of the situation in so far as New Zealand is concerned. These are matters that will be dealt with at the Wellington J conference on Thursday."