PEST CONQUERED

Ashburton Guardian, Volume 57, Issue 26, 10 November 1936, Page 9

PEST CONQUERED

PRICKLY-PEAR MENACE. SUCCESS IN QUEENSLAND. “Practically all the land over which prickly-pear had reigned supreme for many years has now been brought into production, and the remarkable change thus brought about is reflected] in the general progress and betterment of the districts formerly afflicted,” stated the Minister of Lands in Queensland (Mr P. Pease) recently. “Sufficient is now known,” he added, “to say definitely that the great menace of prickly-pear in Queensland is gone, ond what was regarded a short time ago as a most serious problem is now looked upon as just an ordinary pest of the vegetable kingdom.” It was true, said Mr Pease, that regrowth of prickly-pear from seed that lay dormant for years had occurred in successive waves, and equally true that those ever-lessening waves had been swept away like the original growth by the persistent attacks of the cactoblastis insect. Astonishing Transformation. On looking back over the past 10 or 12 years, it was astonishing to realise the great transformation that had taken place in Queensland over the vast area that was then regarded by many as irretrievably lost to pricklypear. The success that had attended the efforts of the responsible authorities charged with the conduct of a general campaign against the prickly-pear menace was truly phenomenal and stood as a shining example of combined scientific and administrative accomplishment. It was doubtful, added Mr Pease, whether the historical records of any country could reveal a biological experiment anywhero approaching the magnitude of the one conducted in Queensland and in the sister State of New South Wales. This splendid accomplishment had been accepted in such a casual characteristic Australian manner.

The whole trouble was started a good many years ago by the introduction of the plant without .proper investigation beforehand. Cuttings were subsequently distributed to various districts and in the course of time the growths came to be viewed in the nature of a pest. The position, gradually became worse. Pastoral lands were overrun with such dense patches that they rapidly became quito useless and unproductive.

Vast Area Once Affected. There were numerous instances where settlers were definitely compelled to leave their homes and abandon their holdings to the ever-increasing growth of prickly-pear. The peak year of its growth was about 1924, when in Queensland alone about 26,000,000 acres or over 40,000 square miles, had become infected. This infestation extended roughly from the New South Wales border northerly beyond Emerald on the Central railway and westerly almost to Oharleville on the main western line. Moreover, at that time it was estimated to be spreading at the rate of nearly 1,000,000 acres, or over 1300 square miles, a year. Following the Royal Commission in 1.923, the Queensland Prickly-pear Land Commission was constituted. It carried out a vigorous policy and within the short space of three or four years published the announcement that the spreading growth of prickly-pear had been definitely arrested. Lost Territory Restored. The colossal expenditure that would have been required put the matter of eradication of the pest by chemical or mechanical means quite out of the question. The scientific investigations being carried out overseas by the Commonwealth Prickly-pear Board, with which authority the State Prickly-pear Commission was allied, led to the introduction of the Cactoblastis eactorum, a boring caterpillar, from South America. After exhaustive tests that fully proved its extraordinary working capacity, as well as its abstension from attacking economic crops, the insect was liberated and distributed throughout many of the infested areas. The result, concluded Mr Pease, was a revelation. In a comparatively few years it restored to the State a vast territory that had been virtually lost, the value of which could not he expressed in monetary terms. It w r as inestimable.