Interest In Control Of Briar

Press, Issue 31095, 25 June 1966, Page 8

Interest In Control Of Briar

At the annual conference of South Island high country sub-sections of Federated Farmers in Timaru this week, Mr R. J. Lee, of Cardrona, in Central Otago, said that they had been told that Dr. J. M. Hoy, of the Entomology Division, had a parasite that would control briar. But while they had had assurances that Dr. Hoy had such a control, they also had information from other sources that this was not so.

Dr. S. N. Adams, director of the Tussock Grasslands and Mountain Lands Institute, said that from his recollections of a talk he had with Dr. Hoy a few months ago they did not have anything just round the corner. They were, however, in touch with the Commonwealth Institute of Biological Control. Briar was a European plant and and they were hoping that they might get a European insect to deal with it.

The conference approved a remit from the Otago subsection seeking the fullest possible information about the possible release of a parasite to control and eradicate briar. It was stated that the South Island high country committee would seek to obtain clarification of the position from Dr. Hoy. Dr. Adams said that Dr. B. P. J. Molloy, of the Department of Agriculture, and Dr. I. D. Blair, of Lincoln College, were interested in a disease that was killing briar

and this would no doubt be followed up. There was a possibility that a disease would crop up that would be useful in controlling the weed.

In the Glazebrook area in Marlborough, and also in Otago, there were some weak briar plants said Mr R. W. Wilson, chief pastoral lands officer of the Lands and Survey Department.

The conference also approved that urgency should be given to making information available to runholders about the ecology and habitat of briar and that investigations should be made into the role of oppossums and hares in the spread of briar.

The conference spent some time debating a reported scientific view that the briar problem was possibly not so much one of spread as of growth of plants that had been in the ground for a number of years. A number of runholders were strongly of the opinion that briar was spreading, even alarmingly, but Mr R. S. A. Chaffey, of Mount Possession station in Mid-Canterbury, said that an examination of briar in his area indicated that there was not now a great problem of spread, but that briar plants which had been in the ground for a number of years were growing under favourable conditions.

“If it does not spread and germinate to any extent how is it so widespread?” asked the chairman, Mr P. C. Ensor.

Dr. Adams indicated that the Tussock Grasslands and Mountain Lands Institute would be publishing in its journal an article by Dr Molloy, who has done extensive work on briar. Runholders emphasised during the discussion that information was wanted in the near future.' Mr Ensor said that what worried him was people should go on using hormone weedkillers on briar at considerable cost.

During the discussion Mr Wilson said that he had found that on areas well grazed by sheep, control was much better than where the country was lightly grazed.' On the real high country Mr Lee said that it was i necessary to spell winter 'country during the growing ! season and it was then that the briar also got away. Sheep would only eat briar where the area was overstocked, and he said that where a runholder grazed his winter country over a' good part of the summer he had no briar problem.

With subdivision of the winter country with fences Mr Wilson suggested that it might be possible to hammer the country, say every three years, and so keep the smaller briar in a fairly satisfactory state.