PESTS IN ORCHARDS.

New Zealand Herald, Volume LVII, Issue 17664, 28 December 1920, Page 5

PESTS IN ORCHARDS.

♦ NEW METHODS OF CONTROL. - INOCULATION OF TREES. INSECTS FOR WOOLLY APHIS. Some interesting remarks on various fruit pests were made by Dr. R. J. Till- '' T yard, biologist to the Cawthron Institute, i ' Nelson, in his recent address to a meet- I ( ing of fruitgrowers at Motueka ' Dr. Tillyard said thai shortly before he ' left New Zealand for England and Europe he gave a lecture on woolly aphis, and ' had gone away with th e impression that , ' it was one of the worst pests—and he : still thought so. But in the meantime ', "j other troubles had arisen, which seemed i Ito overshadow it. He had " kept his eye" on it, aod thought if a cure for it could be found it would be of great advantage i ! to orchardists. He had learnt one in- ' ; terestin<* thing on his travels—that the j . I new method of inoculation which had ■ i been laughed at more or less had been , taken up seriously in Europe, particularly I . jin ltalv. The Italians were very keen on j I keeping their orchards clean, and their | markets depended upon keepinc their fruit ! , I free from disease. It had always been I I remarkable to him that people could buy I i a clean Italian lemon in Sydney, but not i , |an Australian one. This made him j ! realise that the Italian methods of control ] were very good. Italy wak a <rreat ex j nortine country, and they had at the j , head of their departments some very re- j \ j markable men. , Fighting the Woolly Aphis. Speaking of his visit to America. Dr. | i Tillyard said he found feverish activity ; ( I there in regard to orchard pests. In I Maine he found they had been doing a ' I lot of work on woolly aphis in endea j vouring to find the natural enemies of ; : • the pest. The action of an insect in I • I its native land, said the speaker, was i very different from the action in the j country to which they were imported. ! He had come to an arrangement with an I American scientist to be supplied with I these natural parasites in return for I some from New Zealand. A certain j variety of fly had done good work, and I had had a great effect in reducing the I virulence of woolly aphis. In Washington they had a variety of wasp which was the natural enemy to the aphis. He was trying to get a supply of them, and he was hopeful of introducing a eery efficient parasite. In British Columbia ' and California a ladybird dealt very severely with woolly aphis. The insects ; hibernated in the winter, and experts : collected them, and in the spring they i were supplied to orchardists. They were so keen on keeping these natural enemies in America that they were trying to get j a law passed prohibitine a single speci- \ men being sent out of the country. He had put in a claim for some of them, and ; hoped to obtain a quantity in a fewmonths. America was the home of the woolly aphis, and it was to this country New Zealand would have to look for the ! natural enemies of the pest. There was a i general feeling that a certain group of insects, the lace wings, had not been properly tried. He had done a great deal of work with this croup—the green lace- j wing fly. New Zealand, so far as he ! knew, was the only cduntrv where there j were none of these* insects." Their natural food was aphis and scale, and he had been given permission to introduce one of the varieties that were beneficial to orchardists. Injection of Chemicals - All over-the world, continued Dr. Tillyard, they heard the same cry that industries were being threatened by insects and blights. They could take that as a fact. In Italy they did not stand still, and the leading men got to work and" injected chemicals into the trees. The scheme was a success ; but the method had been kept secret. He understood the results were very fine. It seemed an established fact that Italy had a very good remedy which apparently Vas going to do away wuth spraying of apple as well as citnis fruit trees. The Cawthron Institute would go in for experiments, and if the right solution could be found they could do away with most of the sprayings. From evidence he had gathered in Europe he thought it was extremely likely that in a few years they would have a sure method to control the pests. In Sydney a Mr. Smith had started experiments in inoculation, and had tried a number of different mixtures, and he was now working in conjunction with a Mr. Selkirk. Letters received from Mr. Selkirk pointed to the fact that they had evolved a very successful- formula, which had been patented, and would be put on the market. In a further reference to spraying, Dr. Tillya-d said he had ascertained in regard to woolly aphis that orchardists in ' fornia and British Columbia were fully j convinced that theS strength of the spraying material did not matter so much ; but the pressure with which it was put on was the main thing. A nozzle pressure of 2001bs. was the minimum laid down by entomologists. Experts stated that the strength of the material could be reduced by perhaps half if increased pressure was j used. In reeard to woolly aphis he had found that it was not taken very seri- j ously in Eneland, France, and Belgium, i Leaf aphis did more damage oR the Con- j tinent than woolly aphis. ■ == i