rnOCEEDIXGS OF THE THIRD ENTOMOLOGICAL MEETING 



765 



invisible bacterial and fungal diseases in the potatoes. An experiment 

 carried out in 1912 showed beyond doubt that even where the moth 

 pest was excluded the rots could continue their destruction. Two 

 lots of 5,000 lb. each were kept under observation. One was fumigated 

 and the other unfumigated, and both were kept in two separate rooms 

 well ventilated and cool. Forty-five per cent, of the potatoes were 

 recovered from the fumigated lot while all the potatoes in the unfumi- 

 gated lot were lost by rots within a period of three months. This experi- 

 ment showed conclusively that the presence of moths and their larvse 

 in the potatoes helped the destruction to a very large extent. 



Continued trials have shown that the control of the moth is a com- 

 paratively easy task if only the various forms of rots could be eliminated. 

 The larvae of the moth do not destroy the potato except shghtly for 

 seed purposes. It might shrink a httle more than when it is kept 

 free from its infection. Only a few eyes will be injured out of the many 

 that the potato possesses capable of sprouting. No cultivator utilizes 

 rotten or even half-rotten potatoes for seed. But he has no objection 

 to utihze wormy ones for seed and actual counts from a number of fields 

 during the planting season have shown that on an average no more than 

 10 per cent, of the setts have had their eyes injured by the larvae. 



Further observations of the heaps during the period of storage show 

 that the temperature is also a controlling factor which must be taken 

 into account. 



The moth was equally bad in all the heaps. The percentat^e loss 

 shown in the above table includes only those thrown away as beinf^ 

 rotten and useless. The selected potatoes were pronounced to be quite 

 good for seed purposes even though they contained more than 50 per 

 cent, insect attack. A close scrutiny of the table shows that the depth 

 of the heap bears a close relation to the loss sustained and also to the 

 temperature of the heaps. The deeper the potatoes are stored the higher 



