BLACKBERRY

Hokitika Guardian, 12 March 1932, Page 6

BLACKBERRY

ITS ERADICATION. EXPERIMENTS AT TEMUIvA. The New Zealand Department of Agriculture has for some time past been conorned with j the alarming spread of the blackberry pest, and in order to induce those interested to experiment in the direction of devising means of totally eradicating the pest, the Government offers a large bonus to anyone who can successfully treat blackberry in such a manner, that by experiment it can be proved to be a means of completely eradicating it. About four months ago an officer of the Department of Agriculture visited Mr George Pierce, manager of the Temuka gasworks, who was conducting experments with the use of distilled coal tar, and took away with him a sample root of blackberry which had been treated by Mr Pierce’s process. The plants show signs of tile treatment'in about'a fortnight, and eventually die altogether. To Mr Pierce’s knowledge this product of coal lias not been exploited previously. The cost at the works would be about sevenpence a gallon. It should be applied neat, preferably in the earlier spring when the plants are young and commence to produce young shoots. Mr Pierce explained to an interviewer that the process he was experimenting with would not destroy the growth of grass permanently, but it would naturally take some time before grass grew after the soil had been treated. The best way to apply the solution was to pour it neat right into the centre of the plants, which meant quick penetration and dry ground would he better suited than damp as it would give the product a better opportunity of doing its work.

EXPERIMENTAL PLOT. Mr Pierce showed a small plot on the railway reserve a short distance from the works, where the effects of recent experiments could easily be seen. Dead stems were unearthed, and intermingled with the soil were traces of naphthalene, the solid cyrstnl'iim hydrocarbon obtained from the coal tar by distillation. Small shootj tnat were uneartued showed no signs of life. Tlie liquid when applied kills the roots and its appendages for about one foot in circumference from the centre of application, but Mr Pierce does not claim that it would kill the shoots that were further out from the main plant and gave no indication of their presence beforehand, because the leaders from the main root would be under the ground. Mr Pierce estimated that ten gallons of tlie liquid would kill a large heap of backberry bushes that was growing close to the plot recently operated on the plot during the last three months, as far as he was aware no previous attempts at eradication had been made with his process. The blackberry plants be experimented upon were not planted for experimental purposes, but simply treated from their natural growth.

Questioned on the use of sodium chlorate, which had been to some extent adopted by the Department for i eradication, Mr Pierce claimed that l his product was more effective and 1 less dangerous to use. Sodium ehlorI ate was highly inflammable and li- | aide to be affected by the sun, whereas this was not so with distilled coal j tar 'which could be used with perfect • safety.

On some farms in the hills district or the Geraldine County, where the blackberry flourishes in its native state, goats have been turned loose with the effect of keeping it in check, but this is by no means likely to dispose of the pest. While these goats do good in one way. the. benefit derived from them is largely discounted by the harm they do in other directions.