ROOT KNOT IN FRUIT TREES.

Otago Witness, Issue 3263, 27 September 1916, Page 8

ROOT KNOT IN FRUIT TREES.

TO XBB EDITO3. g IR According ro mi article by Mr E. W Ivorv, jun., in jour issue last week, it would "appear to the general reader that many fruitgrowers in New Zealand are at the present much "agitated" over the importation from Australia of large numbers of diseased trees. During a recent visit ro all the fruit districts of Central Otago and Nelson, it was my privilege to discuss tin's subject with many practical and prominent fruitgrowers .-Hid." instead of finding them "agitated" about it, could not help remarking how unconcerned they were in the matter, and how unanimous in their opinions of the results. It is useless for me to attempt to discuss the scientific aspect of root knot as a "disease," or even as a development injurious to trees, when so many learned

authorities differ, not only in the dominion bul in the commonwealth, and most oi thu States of America—lor although Mr ivory quotes one, there aro others just as decidedly against it. The statement that these trees "rarely live over 10 years, and what fruit is borne on them will be undersized," is not sustained by proof, either in Otago Central, which is particularly referred to, or the Nelson district. Ever since the use of the Northern Spy (over 25 years) by Australian nurserymen, as the cleanest and healthiest stock in which to work trees, the root growth produced has been the same. During that time, fully two-thirds, at least, of the orchards about Beaumont, Millers Flat, Roxburgh, ISttriek, Alexandra, Clyde, and the Cromwell districts haw been planted with imported trees. Out of so many 1 would ask Mr Ivory to name one which has caused such disastrous results as ho predicts or, by spreading, has affected the industry of those districts. On the other hand, many orchards at Cromwell, Roxburgh, Ettrick, and Beaumont, which have been planted from 12 to 20 years almost exclusively with Australian trees, show no signs of deterioration, and last season produced enormous crops of unequalled fruit. Accompanying"recently a party of Government experts, leading New Zealand nurserymen and prominent fruitgrowers to the Government test plot at Wallaceville (Wellington), further proof was afforded me of the results of these trees. About live years ago some 100 apple trees, of various varieties, specially selected as very badly affected by root knot, hairy root, and crown gall, have been planted with corresponding rows of clean and healthy trees. Although planted on poor soil, -indifferently pruned and little cared for, it was tho unanimous opinion of the party that tho trees look healthy and had made the usual growth (three to four feet) to satisfy any fruitgrower. Wo were also allowed to lift and examine the root result of some ©f these, trees, labelled as badly affected, and noticed not only that the callous growth had disappeared, but a new and vigorous root growth was produced. Mr Ivory says these trees have not yet had time to die. This is very contrary to tho opinion of several experts of the department, but as a practical fruitgrower I only hope to live as long as they will to see the result. Experiments were made, in the same direction, some six years a<j'o by the Victorian department, and also by one of the largest nursery firms, with similar results. Air Ivory Heplorcs tho disastrous loss of hard-earned savings which must result to those planting these trees in New Zealand. Yet during the past 35 years, millions of these same trees have been planted, and arc still being largely planted in Tasmania and through the mainland of Australia, and yet tho industry is prospering almost beyond control. In a letter to the secretary of the New Zealand Association of Nurserymen, the Secretary of Agriculture wrote as follows: "You are no doubt aware that the specially selected specimens of root knot affected trees planted experimentally at Wallaceville have grown quite normally, thus casting grave doubts upon the necessity for condemning for this disease. From tho evidence already available, however, there is no room for doubt that the disease is a much loss serious one than was thought probable a few years ago." When asked for his opsnion regarding the trees "held up" recently at Wellington, a loading officer of the department' unhesitatingly replied that he would not be afraid of planting them. So doubtful and different are the opinions- of c;o many who aro responsible to decide the problem that the _ department* of New Zealand and Australia arc at present making an investigation, both baeteriologieally and otherwise, in order to settle definitely the course to be adopted in future seasons. This, to my mind, is good evidence that the department here is not, as Mr Ivory states, neglecting to safeguard the growers and the industry. As a result, of the action of the department in allowing consignments to be picked ever fit Wellington, I may, on good authority, state that out of one consignment by a single firm of 43,000 trees, not more than 2 per cent.- were rejected after a most stringent inspection. Although Mr Ivory predicts that certain highly placed officials will shake —and probably tho Minister of Agriculture fall from his high office—my private opinion, after 12 years' dealing ..with thorn as an importer, is that they know what they are about, and that the" industry is being placed upon a sure and safe footing. There aro other comments in Mr Ivory's letter which I should have liked to refer to, but for the present will confine myself to tho main issue of his remarks, and leave tho rest to the intelligence of growers to read between the lines and judge' for themselves.—l am, etc., A. E. M'Comas. Two Bays Nurseries of \ ictoria. TO THE EDITOR. Sir,—-In his letter appearing in a recent issue of the Daily Times Mr M'Comas, representing an Australian nursery, has made the best of the ease for imported trees, but as most of his. criticisms are based on distortions of my article, I feel called on to reply. There is no doubt whatever, that in the past, certain New Zealand inspectors mistook the natural rooting system of the Northern Spy apple stock for manifestations of the diseases known as root knot, hairy root, or crown gall. Consequently, suspicion has been laid on perfectly healthy trees, which have since proved by results to bo normal and healthy. Mr M'Comas's remarks regarding such trees do not alter the fact that the true disease of root knot is undoubtedly a very serious matter, and fully warranted the drastic regulations issued by our Department of Agriculture in prohibiting the importation of trees if the smallest proportion of the consignmeni was infected. Mr M'Comas refers to the many successful orchards in the Beaumont. Miller's Flat. Roxburgh, Ettrick, Alexandra, Clyde, and Cromwell districts that were planted with Australian trees. No one has questioned their success, but I would remind Mr M'Comas that these trees had to pass strict Government inspection before being allowed into the country, and Mr M'Comas well knows that many thousand Australian trees have in the past been shipped back to Australia or destroyed. Planters of Australian trees are no longer safeguarded by the inspection at port of entry, as the Minister lias relaxed the regulations, allowing consignments to be sorted over, and trees carrying the infeetion, but showing no visible 1 signs of the disease, to be imported into the country. I am officially informed, however, that a clean certificate cannot be granted for these trees. Please note thai ! I would also point out that the Minister

does not go further than give importers of Australian trees the option to pick the trees over and take those that show no signs of the disease. Tho importer takes the rislc, which, ho passes on to the buyer of his trees. If the importer wisely refuses to accept tiiese trees, the whole consignment is condemned by the inspector, and either destroyed or shipped back to Australia. Trees from an infected nursery aro liable to develop the disease although they show no signs of it when planted. Bolting over the trees at port of entry is no safeguard to planters. The department's inspectors last month seized and burnt over 50 per cent., of a consignment of trees from Island Block as being badly diseased with root knot. These trees came from Australia 12 months ago, passing the inspectors at Duncdin because they showed no visible signs of the disease. " Even the strict enforcement of the present regulations will not .safeguard New Zealand planters, as the trees may be sorted in Australia, and trees may bo shipped that are to all outward appearances clean, and yet carry the infection. Recent bacteriological tests have revealed tlie presence of the bacillus on apparently clean trees from a shipment which contained specimens affected with root knot. Mr M'Comas may cite the cases of trees which were wrongly diagnosed as being infected with mot knot, and which afterwards "made good." He may argue against the seriousness of the disease in spite of the opinion of such experts as Professors Paddock and Whipple, writing after experience of conditions identical with Central Otago. But surely, he doe? not wish us to believe that there is no disadvantage in having a large, ugly, cancerous growth at the root of a tree. —I am. etc.. Ed. Ivory, -Tux. Rr.ngiora, September 21.