FIRE BLIGHT

Otago Witness, Issue 3495, 8 March 1921, Page 7

FIRE BLIGHT

ITS PRESENCE REAL. AUCKLAND, March 2. The doubts cast in a recent article in the Herald by Mr F. R. Field, F.R.H.S., regarding the presence of actual fire blight in New Zealand, are combatted in an interview by Mr G. H. Cunningham, who is engaged in mycological work In the biological laboratory of "the Department of Agriculture. With regard to the identification of fire blight, Mr Cunningham stated that the biological laboratory had been responsible for work in that direction. When the blight first made., its appearance he had personally visited the orchards infected, making a tour of the districts where the pest had appeared. Ho had taken specimens of the infection, and had had numbers of others sent to him in Wellington. The process of identification was exactly to that followed in the medical bacteriological laboratory. Cultures were made, and the development of the bacteria observed, at all its stages. As a result of the laboratory work done the bacteria causing the mischief were identified definitely and beyond all possibility of doubt as that of real fire blight. The hosts that had been infected were apples, pears, quinces, medlars, and the common hawthorn. These were the only hosts that the disease was known to have infected in New Zealand. The contention that the fire blight might have been spread by wind-borne spores was scouted by Mr Cunningham. He explained that the fact that Mr Field mentioned the possibility of the disease being wind-borne showed that he was not really discussing properly-identified fire blight such as haa appeared in the Auckland district at all. The infection of real fire blight could not be wind-borne. Confusion over the appearance of the trees was quite possible, since careful examination and long experience were necessary before it was possible to determine the identity of fire blight bacteria. With regard to the statement that trees which had been infected had recovered and replaced the lost foliage with healthy' young; growth, Air Cunningham said there had evidently been a mistake, for there was no known case in New Zealand of an infected tree having recovered. It was commonly stated that fire blight had been present in the country for many years. The ravages produced in a few months, however, showed that such a dis-ease-producing organism could not have been present for very long without its p.resence being thoroughly well known and feared. Its ravages had been very marked, as was shown by the great damage that had been wrought within a very short time. In about 12 months it had caused damage aggregating many thousands of pounds. The whole trend of Mr Field’s remarks showed that he was confusing one of the stages of the disease with what was commonly known as windburn. It was quite wrong to suppose, concluded Mr Cunningham, that there was no clanger of the disease spreading at other than blossoming time. It was, in fact, spreading at, the present time, and would continue to do so until the dormant season after the sap had descended. The twig infective referred to by Mr Field, Air Cunningham stated, was one 6f the phases of fire blight, and not a separate disease.