CONQUERING A PEST.

Auckland Star, Volume LX, Issue 229, 27 September 1929, Page 6

CONQUERING A PEST.

The revolution being wrought in the prickly pear lands of New South Wales is one of the finest achievements science yet has to its Credit in the direction of biologic control (says the "Sydney Mail"). A few years ago the whole country was alarmed at the spread of the pear, I and pessimists were to be found everywhere holding up their hands and declaring that nothing could stop the inroads of the menacing growth. Many mechanical and chemical schemes were tried to overcome it, but none held out hope of ultimate success until the cactoblastus and cochineal insects were released in sufficient numbers to make their presence felt. How these insects are literally eating out the pear at the rate of 500,000 acres a year is something to marvel and enthuse over. In the last four years 1,300,000 acres have been won back from the prickly pest, and as the war against it progresses the armies of insects are constantly on the increase, so that their victories should be relatively faster and faster. But is is not all quite as simple as it reads. Constant vigilance is necessary to prevent reinfestation, and there is some difficulty in getting the insects to attack the hard old pear. Naturally they prefer the more succulent plants, but those who are directing the campaign—the Pear Destruction Board—are confident that the menace is now well in hand, and that in about ten years' time northern New South Wales will be practically clean. What this will mean to the State it is difficult to estimate. At any rate, allowing for areas that will have to be re-treated, it is safe to say that already about 1,000,000 acres that had been lost to the country have been won back. What wc need now is population to keep these lands free