LECTURE BY DR TILLYARD

Otago Daily Times, Issue 18803, 5 March 1923, Page 3

LECTURE BY DR TILLYARD

“ INJURIOUS INSI'ICTS.” An illustraTcd lecture, under the auspices of tile otiigo Institute, was delivered in the new Medical School on Friday evening by Dr R. J. Tillyard, biologist of the Cawth-ron Institute. Nelson, the announced subject of the lecture being the “Control of Insects. The chair was occupied by Dr Malcolm, übo. iu the course of a tew introductory remarks mentioned llif.Lt the-.correct title of th e lecture was “Control of Injurious losco 15.” Dr Tillyard, who had a numerous audience, said that it was now more than three \ears since his lirst visit to Dunedin. It was through the institute that ho hod been invited to come to Otago, end he bird nail his bands pretty full. We hud not got as many posts in Dunedin as there were in Nelson. He had had an opportunity of going through the fruillands of Otago Central, and had been delighted to see how well they compared with those of Nelson. Fruitgrowing was much better over the Otago Central, where there was nothing like the pests mot with in Nelson. He said ho wanted his audience to take a general survey of the animal kingdom, and try to think of the ordinary idea of that kingdom, ns it was found in the world. There was a division between those who had backbone and those who had not, and at the head of the vertebrate was man himself. In the invertebrate had arisen a class of insect which by its powers of reproduction bid fair to outdo man. It was a, fight between man nad insect. The natural food of both was the same, but insects were able to feed over a far greater range than man. They took toll of everything. They would see the problem before them was a very great one, and might become oven greater as the world grow older, because supplies of food were becoming smaller, and population was increasing. Moans of dealing with the different types of insects had been tried. Tho greater part of the pests in New Zealand had been introduced, unwittingly, but by the agency of man himself, and in order to prevent their continuance what was to be done? Laws alone would not keep them out unless they were rigidly enforced. If a thousand insects were sent to Auckland, and 93 per cent, was destroyed, the whole lot might just as well have been let in, because of the rapid ropdochtction of those left. Ho had been advocating a system which he called island quarantine, the idea being to select an island off the coast with a sufficient area, and place it under cultivation. Young trees should bo taken to that island and cultivated for at least a year, and if they came through for one year they could be certified as clean and taken to the mainland. There had boon bred in Auckland a disease which had got through (he Auckland province and into the Waikato, and had done an enormous amount of damage. It was only a question of time when that would extend to the South Island. Supposing the trees had been planted on an island running seres would have been seen and the trees destroyed. They would never have got to the mainland. It had to be remembered that for every insect or fungoid pest there were 10 equally as bad ready to come in, and if that wore allowed our groat forestry scheme would be spoilt. We wanted to know the habits of every injurious insect. Continuing, Dr Tillyard then went on to speak of the earwig, which was easily controlled. By putting a flower pot; over a dahlia they ran up tho flower pot and could be destroyed. The earwig, he continued, was attacked by a fly, which was in turn attacked by a smaller parasite, which fed upon the flies’ internal organs. So that first there was the vegetable, then the earwig, then the fly, then the parasite, etc. The method of control nature had sot out was wonderfully complete. In New Zealand it could not apply, because we had introduced the earwig which had got in without control. It bad simply been allowed to go ahead, amd we must try and restore tho balance of nature. Dr Tillyard then showed a number of interesting lantern slides, and was accorded a hearty vole of thanks at the close of his lecture.