68 



IRISH GARDENING 



MAY 



duriiit: storiiii;' is almost sure to inU-ct tlic 

 liealtliy ones. llic best way to prevent tliis is 

 to diii; up the attacket.1 plants while the\ still 

 show sijj-ns of the disease, lor, ;is will le 

 pointed out ininiediatel\ , it is by no means easy 

 to separate the infected and the non-inleLted 

 tubers of a diseased crop at dii;t;inj4- time. 



The second reason is that b\ doinj,'' this all 

 infected tubers are excluded from possible use 

 as " seed " for next year. It is probable, thouj^h 

 the question is not entirely settled, that the 

 disease is perpetuated throu,i,^h the plantinj^ of 

 affected tubers rather than throuyfh direct attack 

 every year from the soil. An experiment quoted 

 from the paper referred to above proves at all 

 events that infection crm be carried over to the 

 next crop in the " seed." Twenty-five per cent, 

 of a crop of " British Premiers " suffered from 

 Black Stalk-rot in 1909. "Seed" from this 

 crop, which was apparently pcrfecily sound, pro- 

 duced in 1910 on clean land a crop 94 per cent, 

 of which was diseased. 



Digging up affected plants and tubers early 

 in the season minimises also contamination ot 

 the ground with the disease-producing bacteria, 

 and prevents the possible spreading of the dis- 

 ease to healthy neighbouring plants. How 

 much this spreading, if it occurs at all, takes 

 place is not yet determined ; but the disease is 

 not at all liable to spread in the way the common 

 potato blight does. If the diseased tubers are 

 left in the ground till the whole crop is being 

 dug it happens too often, unfortunately, that 

 those that are entirely rotten are left behind as 

 not worth the trouble of lifting, thus going a 

 long way towards perpetuating the disease in 

 the soil. Where a proper rotation of crops is 

 followed this perhaps is not of much importance ; 

 but it assumes a greater significance where 

 potatoes are grown year after year in the same 

 plot. For this and for other reasons potatoes 

 should not be grown on the same land oftener 

 than once in four years, where that is at all 

 possible. 



Allusion has been made to the necessity of 

 excluding all diseased or suspected tubers from 

 the pits. Every possible care should also be 

 taken to pit the potatoes in good dry condition, 

 to ventilate the heap efficiently, and to protect 

 it so thoroughly during the winter that all 

 moisture is excluded. The common practice of 

 sinking the bottom of the pit six inches or a 

 foot below ground level cannot be condemned 



too strongl\-. Hut all tliese precautions may 

 not be enough unles^ grow ei s insist on having 

 perleclK souinl •'seed." Above all, no "seed" 

 lioin e\en .-i sligl)il\ infected crop should l">e 

 pl.-intetl, lor it is almost impossible to say h\Mn 

 .in external examination uliether or not a tui->ei' 

 is alVecleil. The safest way is to jirocure seed 

 from a district in which tlie disease has not yet 

 appeared. 



-^W 







Flowering Shrubs. 



By F. W. MoORE, M.A. 

 'LKMKNTARV "LlST. —(Cotithiued from pofTc 153.) 



Magnolia .Alexandra 

 ,, conspioua 



parviflora 

 soulangeana 



April and May 

 April, May, and 



June 

 April, May. and 



June 

 June 

 April, May, and 



June 



