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IRISH GARDENING. 



February 



the plots were treated with dififerent kinds of manure. 

 The plants used were peas in four varieties. One of 

 each pair *:>{ plots was sown with inoculated seed and 

 one with uninoculated .seed. There was iinder no soil 

 treattncnt a consistetit incrense in the crop due to inocula- 

 tion, and the conclusion arrived at, is, "that the 

 inoculation of leguminous crops with ' nitro-bacteria ' in 

 ordinary garden soil is not likely to prove beneficial." 

 In one respect the results were somewhat surprising^, 

 as Mr. Chittenden says that in " seven out of the 

 twelve plots in which inoculated seed was sown gave 

 smaller crops than the corresponding uninoculated plots, 

 and one gave an equal crop," the advantage of un- 

 inoculated over inoculated seeds in the entire series of 

 experiments amounted to an increase of 14 per cent, per 

 weight of produce. While it is difficult to conceive any 

 really practical advantage in inoculation in ordinary 

 garden soil, it is equally difficult to account for an 

 actual disadvantage. In the light of our present know- 

 ledge respecting these nodule bacteria, the practice of 

 inoculation as a means of increasing the produce of 

 leg^iminous crops cannot be recommended. Of course 

 we find that a large number of private growers have 

 written testimonials as to the efficiency' of inoculation 

 (any purveyor of even the most useless of quack nostrums 

 can secure the same), but we know of no case in which 

 inoculation has been tested in ordinary garden soil {and it 

 is only with such soil that gardeners are really interested) 

 under a rigid system of control, to yield an increase 

 of produce that would represent a profit to the grower. 



American Goosebeny Mildew. 



FROM Professor Jacob Eriksson, of Stockholm, 

 comes a leaflet on the above subject reprinted 

 from the Praktische Blcitter fiir PJlanzenhau und 

 PJianzcnschutz, Heft 2, 1908. After making a slight 

 correction in what has hitherto usually been accepted as 

 the proper scientific name of the fungus, and stating 

 that it has been known for at least seventy years, he 

 goes into the question of its recent introduction into 

 Europe. It will be new to many of our readers to find 

 that this has taken place both on the east and on the 

 west. Its discovery in the north of Ireland in 1900, 

 which until recently was supposed to mark its first 

 appearance in Europe, was, however, preceded by an out- 

 break at Winnitzy, in south-west Russia, ten years earlier 

 — viz., in 1890 — and by 1904 it had already appeared in 

 ten widely separated localities in European Russia. 



Dr. Eriksson calls attention to the increasing intensitv 

 of the disease, to the fact that no one variety of goose- 

 berry seems more resistant to the mildew than another, 

 and that as well as attacking the gooseberry it has been 

 found on the red and black currant, on Ribes aureum, 

 and in one locality in south Sweden on raspberries. He 

 states that in many instances three distinct periods of 

 attack occur during the year in Sweden, the first being 

 during the second half of June, when the young berries 

 and young shoots are involved, infection taking place 

 from the hibernated perithecial stage of the fungus. For 

 the second or summer outbreak (latter part of July in 

 Stockholm), partly on young, newly planted bushes and 

 partly on old ones, he states that the infection is not 

 always due to conidia from neighbouring affected plants. 



but that it must be accounted for, in his opinion, by the 

 presence oi an internal germ of disease which was 

 already inside the young plants when they were trans- 

 planted, or which remained in the older plants from a 

 previous year in which \.\\e\ were diseased. It will be 

 remembered that Dr. Eriksson is the author of the so- 

 called " mycoplasm " (or internal germ) theory in 

 connection with the ru.st of wheat and other cereals, and 

 although he has assiduously promulgated his views on 

 this subject for some years the theory has gained as yet 

 \'&vy few adherents amongst mycologists. In this 

 case, also, very definite scientific evidence for his 

 present opinion will have to be forthcoming before this 

 peculiar view is likely to be seriously adopted. The 

 third period of attack, August to October, is put down to 

 infection from neiglTbouring diseased bushes. 



\\'ith regard to preventive measures, he states that 

 spraying during the vegetative period is only of ephemeral 

 value, for the mildew appears repeatedly afterwards on 

 the developing young shoots. Such sprajing he con- 

 siders to be a waste of time and money. Removing and 

 destroying the diseased shoots during the summer is 

 also, he considers, of little real use, and even cutting the 

 bushes right back to the ground, burning the cuttings 

 and liming the soil, has not, in any case known to him, 

 eradicated the pest. He then returns to the question of 

 an internal ^* sotnethijig" the presence of which he be- 

 lieves it necessary to assume in order to explain cases 

 of the reappearance of the disease for which the ac- 

 cepted views seem insufficient to account. He assumes 

 that the fungus lives internally in the attacked plants, 

 perhaps in a scarcely discernible form or shape, and 

 poisons the whole shoot. It is further assumed that 

 at the end of the period of growth — in late autumn — 

 the poisoned sap flows down into the stem and the roots, 

 to ascend again in the next spring and cause a fresh 

 outbreak of disease at the specified time. 



He has no faith in the certification of nurseries as free 

 from disease even after most careful inspection, for in 

 several cases where he himself and other well-qualified 

 investigators inspected nurseries with the utmost care 

 in September, and found no signs whatever of the dis- 

 ease, it appeared, nevertheless, in the following year. 

 It is, therefore, not possible to certify- b}- inspection that 

 a nursery is free from disease, but onlv that the fungus 

 could not be discovered there. 



The only certain and sure method o( combating the 

 disea.se lies, according to Dr. Eriksson, in the total eradi- 

 cation and burning of diseased bushes, and this work 

 must be taken in hand at once before it becomes too late. 

 This is the only way in which the gardens which are 

 still healthy can be so preserved, and in localities where 

 the disease is present no new planting should be done 

 for two or three years. In ven,' badly affected localities, 

 where it is already too late for this, the individual owner 

 has the choice of either total eradication and burning, or 

 of cutting off the tips, spra^'ing and liming in late 

 autumn. These conclusions as to remedial measures 

 are practically the same as those arrived at by our own 

 Irish Department of .Agriculture last year, and have been 

 put into practice during the past sea.son. It is to be 

 hoped that tangible results will ensue from the measures 

 taken, and the coming year should afford useful evidence 

 in this direction. G. H. P. 



