CATERPILLAR PEST

Rotorua Morning Post, Volume 3, Issue 663, 16 October 1933, Page 7

CATERPILLAR PEST

ashburton's plague FARMERS CONCERNED ABOUT POSSIBLE RAVAGES OF I WORAL .i" A LEAVE PASTURiES BARE I The plague of caterpillars which h'as 1 made its appearance in the Ashburton •county durang the last week is still prevalent, and most of the damage so far haiT ibeen confined to pastures (says the Press). With the continuation of the dry weather, farmers are still concerned about the ravages of the pests, which are leaving nothing but bare ground in their tracks. ' It has heen urged by landholders that either the Agricultural Department or the Ashburton County Council should take up the matter of endeavouring to ei*adicate or control the caterpillars. Mr. E. M. Bates, of the Field Division of the Department of Agriculture, Ashburton, visited some of the areas affected at Dromore and Fairton and gathered several of the caterpillars, which he forwarded to the ' entomologist of the Department of Agriculture for identification. Speaking to a representative of the Press, Mr. Bates said that in his opinion the caterpillars were most likely cutworms or surfa.ee caterpillars, terms which were applied to the larvae of a number of different species of moth which caused damage to cultivated plants in most countries of the world. They were usually of the aigrotis family. The mild, dry season during the last ' twelve months had been largely responsible for their prevalence. The adult moth appeared from about December' to the end of January and laid eggs on leaves or strms of weeds and cultivated plants, and the caterpillars' were hatched out in about a fortnight. About October of each year the caterpillars were becoming full-fed and turned to brown chrysalises in the soil. When they went into that resting stage they did no more damage, stated Mr. Bates. By about December they came out of the pupae cases as adult moths. Cutworms were most likely to he troublesome on weedy land or in weedy crops. Potatoes, mangels, and cereals were frequently attacked. holes were often made in potatoes, wbile turnips and mangels were often cut helow the surface of the soil. Grass lands for wheat sowing the following autumn should be broken early in January to avoid attacks of cutworms or leather jackets (dladdy lon.g legs' larvae), said Mt. Bates. Messrs. H. G. Kemp and O. Vial, of Ashburton, experimented with the application of creosote on the catrrpillars at Fairton on Tuesday, and found it a most effective means of killing the pest. As a result of the experiment on a small scale, it was considered that if the creosote was sprayed on the ground with a pump, the caterpillars could be confined to an are'a instead of spreading over several paddocks. The only disadvantage was that where the mixture was sprayed the ground would be unproductive for a time. It was considered that the eradication of the pest would more than compensate for this. An Expert's Report. Dr. F. W. Hilgendorf, of the Wheat Research' Institute, and Mr. L. Morrison, entomologist at Lincoln College, went to Pendarves on Thursday. The old brown top field next to that where the caterpillars were first seen, 1 states Dr. Hilgendorf, is about thirty acres in extent, and the caterpillars are all over it — perhaps one to every square foot. They are all moving towards the west, and the advance parties reached a wheat field on a front ' of ten chains or so. Th'ey have penetrated to a depth of about three chains on this front, and have eaten the wheat down right to the ground or below it, so that the land is completely bare. It is not until after the soil has heen scraped away that any wheat plants at all can be sceri. A singie caterpillar was seen to eat a wheat plant down to ground level in about 15 minutes, and seven caterpillars have heen observed on a singie plant. The remedial measures so far taken are as follows: — First, the brown top field has heen ploughed round with two furrows half a chain apart, and where the furrows are parallel to the line of niarch small cross' furrows have heen dug to lead the caterpillars ■into the main- furrow. In this pits a couple of feet deep have been dug every few chains, and the caterpillars march along until they f all into the pits, where they are killed with' a rammer when they get six or eight inches deep. This has cut off the invasion of the wheat field to a very considerable extent. The caterpillars in the wheat field h'a.ve also heen killed to some degree by rolling it twenty times or so with Cambridge rollers. The treatment is not completely successful, as twenty caterpillars were still found alive n a singie square foot, hidden an inch or less under the loose clods. Colonies of the caterpillar pest have been discovered in various parts of the Ashburton County during the last week, but from. reports to hand no serious damage has heen done apart from the cating out of the pastures, states the Christchurch Press. In addition to Lauriston, Fairton and Pendarves, hordes of the pest have made their appearance at^ Montalto and Sherwood. The problem of deal:ing with the caterpillar was discussed briefly by the Ashburton County Council on Friday, but beyond deciding to place the council's large steam roller at the disposal of farm ers as a means of killing the pests no action was taken.