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Show TWO NEW FOLIAGE TROUBLES OF APPLE - -- - -..I i 1-4 BRANCH BEARING LEAVES AFFECTED WITH CHLOROSIS. I The portion of the young branch rop- resented in Fig. 1 gives an idea of th characteristic appearance of the diseased dis-eased foliage on the tree. The leaves shown in Fig. 2 were selected to show Individual variations. The two on the extreme left of this illustration are far from typical of the great majority and represent about the only specimens of lids character found, out of probably more than one hundred collected. While the yellowing appears to start frequently along the line of the larger leaf-veins, it is just as likely to appeat first in the tissues midway between them. In the preliminary studies made in the field no definite clue could be obtained ob-tained as to the cause of the trouble. Silver Leaf. As far as the writer has been able to learn, the only references to this disease in American literature are contained con-tained in the writing of Guissow. In 1910 he recorded its presence in Nova Scotia. In giving the characters of the disease he mentioned that the leaves on the affected branches have a silvery appearance or a milky white gloss, particularly par-ticularly on the upper surfaces. The epidermis on the upper surfaces of the leaves is also very brittle. In this paper pa-per he states that when a branch is attacked it dies, as a rule, after one or two years, and that a tree once attacked at-tacked by silver leaf will eventually succumb. In this paper he mentions that some European writers consider the disease to be physiological, but says that it is remarkable that Ste-reura Ste-reura purpureura Pers. is constantly associated with it. (Fly WAKNRR J. MDltflU, Pli. D., Piltll-nlrtKlHt, Piltll-nlrtKlHt, Maine AKncultural Kxperimtint Siatlnii.) la the Hummer of 1915 two foliage troubles of the apple were observed, of which there appears to have been no previous record in this state. One of lhe.se, which the writer has called chlorosis, was widespread and common com-mon in a single orchard and occurred to it certain extent on Individual, scat-lered scat-lered trees In the same locality. No definite cause could be assigned to the condition. The other, a disease previously previ-ously reported In Europe, Canada, South Africa and New Zealand, is known as silver-leaf and was found to be fairly common in various parts of the orchard-growing section of the state. Chlorosis. to September, 1914, some diseased apple leaves were received through the college of agriculture from their extension exten-sion representative in Franklin county, air. W. M. Morse. At that time the I rouble was known to exist on a single free, growing by the roadside in Liver-noore Liver-noore Fulls. Further observations by Mr. Morse In the spring and early summer sum-mer of 1915 shewed that this condition of apple foliage hind a wider distribution distribu-tion than was fcrst Indicated, and led to a visit to the locality by the writer under his guidance. As fiir as observed this chlorotic effect ef-fect on the leaves was limited to apple trees in a rather restricted area of adjoining ad-joining portions of the towns of Jay and IJverraoro. Although several less isolated affected trees, including r.aldwin. Northern Spy and Harvey varieties, va-rieties, were seen which were growing on high, well-drained land under good conditions, observations in Jay were confined principally to a single orchard of Baldwins of two or three acres in " extent. This orchard was on rather low land, naturally moist, but was fairly well drained with open ditches. The leaf trouble was restricted to no particular part of the orchard but was apparently not quite so severe on the higher portion. However, the trees here were eoinewhat younger than the rest. TLs aiajority of those affected were probably twenty-five to thirty years old and may have been older. While they had apparently been neglected neg-lected up to a few years ago their treatment in this respect did not differ dif-fer from that given to the trees in many other orchards in which no such trouble occurred, For the past few years they have been cultivated, fertilized ferti-lized and pruned. i The trouble appeared on the younger -ub well as the older branches, and is In no way connected with the normal yellowing and falling of the inner and more shaded leaves which is of common com-mon occurrence. Neither Is it associated associ-ated with any form of spray, for it occurs on sprayed and unsprayed trees alike. However, leaves so affected are easily and sometimes severely injured by lime-sulphur, used at a dilution which gave absolutely no injurious effects ef-fects on the healthy foliage of the same tree. The leaves showing the chlorosis here described are, as a rule, variously spotted or mottled with irregular splashes of yellow, giving a variegated sppearance. No opportunity was afforded af-forded to follow the course of the dis-ense dis-ense through the season, but it is thought that the yellowing is progressive, progres-sive, eventually involving a large part if not the whole of the leaf, for some were collected which showed but little t the original green remaining. Figures 1 and 2 illustrate the ap-nearnnce ap-nearnnce of the affected leaves much better than any written description. . ... .. . 0m m 83 SS&- fefe i 1 StHKS? s?-r LEAVES SHOWING VARIATIONS IN CHLOROTIC EFFECT. |
