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Potato Leap Curl Demonstrations . [Feb., 



to minimise as much as possible the effect of local conditions and 

 to render the demonstration of the widest service, the trials were 

 located at the twelve advisory Colleges or Institutes situated in 

 the twelve provinces into which the country is, for agricultural 

 educational purposes, divided. 



The variety selected for experiment was Arran Comrade, the 

 seed being grown in the neighbourhood of Edinburgh, 1 cwt. 

 of healthy seed and 1 cwt. of seed affected with Leaf Curl were 

 sent to each College. The healthy seed was obtained from a 

 field carefully examined and found to be entirely free from 

 disease. The second lot of seed was from a field a few miles 

 distant which was generally, though slightly, affected with Leaf 

 Curl. The land here was, if anything, slightly more moist than 

 where the healthy seed was grown. The attack on this field 

 was so slight that some growers would probably have regarded 

 the crop as healthy, and even by those conversant with Leaf 

 Curl it might have been regarded as sufficiently good for seed- 

 purposes. The following figures supplied by the Institutes show 

 how much the yield is reduced when seed affected with Leaf 

 Curl is used : — 



Aberystwyth, University College of Wales. Diseased Yield 

 Curled. Healthy. (Healthy=100') 



Weight ... 3 cwt. 13 lb. 8 cwt. 4 lb. 437 



No. of plants ... 463 522 



Long- Ashton, Research Station, Bristol University. 



Diseased Yield. 



Curled, Healthy. (Heal thy =100.) 



Weight ... 4 cwt. 3 qr. 2 lb. 13 cwt. 6 lb. 36'5 



The " take " very uniform in both plots ; Leaf Curl plot remained very 

 stunted. No allowance for " misses " was necessary. 



Reading, University College. Diseased Yield. 



Curled. Healthy. (Healthy =100.) 



Weight ... 2 cwt. 7 lb. 8 cwt. 1 qr. 14 lb. 49'6 



No. of plants 637 637 



Plot with healthy plants ploughed two months before planting and 

 subsequently cultivated. Plot with Leaf Curl plants not well cultivated ; 

 cabbage stumps left until dug just before planting. 25 per cent, added to 

 third column to allow for this disadvantage. 



Newton Abbot, Seale Hayne Agricultural College, Devon. 



Diseased Yield. 



Curled, Healthy. (Healthy=100.) 



Weight ... 1 cwt, 2 qr. 26 lb. 5 cwt. 2 qr. 51 '5 



A number of misses occurred in Leaf Curl plot, and therefore an allowance 

 of 20 per cent, has been added to third column. With a very few exceptions 

 the curled plants produced only one 1 potato of ware size and three or four 

 email tubers ; healthy plants produced, on an average, four of ware size. 



