SCIENTIFIC COMMITTEE, MAY 9. 



Ixix 



there were so few of them that they could not have done any appreciable 

 harm ; there were also a few mites belonging to the genus Trombidium, 

 but they are quite harmless. There were a number of empty egg-shells 

 on all the shoots, and a few unhatched eggs, which I will try to rear. 

 The buds do not look as if they had been injured by insects, but as 

 though the frost had killed them, or that much maligned combination of 

 circumstances commonly known as the weather. I should certainly 

 recommend the use of the caustic-soda wash next winter." There was no 

 sufficient evidence to show what had gnawed the apple-buds received from 

 Mr. Dunlop. 



Montbretia Corms Failing. — Mr. Massee, V.M.H., reported that these 

 corms had for some reason or other failed to form new corms last season, 

 and were therefore not growing this. 



Deterioration of Potatoes. — Mr. Chittenden read the following 

 summary of the discussion on this subject, which he had drawn up at the 

 request of the Committee : — 



I. Do potatoes deteriorate ? It is important to note that deteriora- 

 tion may take place from a commercial point of view, or from actual 

 degeneration of the plant itself. (See II. below.) 



1. In the broad sense they undoubtedly do deteriorate. 



2. But deterioration per se also seems to occur. E.g., ' Buffs ' 



and ' Dons,' previously good, succumbed to disease in 1845. 

 ' Victoria ' degenerated in time both as a cropper and in 

 disease-resisting power. ' Dunbar Begent,' with its acknow- 

 ledged excellent qualities, can have disappeared for no other 

 reason than because it had deteriorated. Varieties degenerate 

 sooner or later both in productiveness and resistance to 

 disease, sometimes in as short a period as six years from the 

 raising of the variety. 



II. What are the evidences of deterioration ? 



1. As shown by the plant itself, (a) The leaves grow curly and 



stunted, (b) The plant does not develop properly, or (c) even 

 fails to appear above ground at all. (d) The plant offers less 

 resistance to disease (in eight years a reputed disease-proof 

 variety became much diseased). 



2. From the growers' point of view, (a) The produce is much 



lessened (in one case cited by 50 per cent, after two years) 

 when grown on the same soil, (b) The size of the tuber is 

 reduced (" in fifteen years the potatoes were no larger than 

 marbles "). 



III. Why does deterioration occur ? 



1. It may be brought about by local conditions. 



a. Treatment. (1) Wintering tubers under conditions causing 

 premature sprouting. (2) Growing continuously on the same 

 soil. (3) Unsuitable manuring. (4) Possibly by selection of 

 small tubers (but this is by some regarded as unlikely). 



