706 PROCEEDINGS OF THE THIKD ENTOMOLOGICAI, MEETING 



the loss by rots and this may possibly be accounted for by the higher 

 temperature generated in the depths of the heaps. Ventilation of the 

 heaps must be secured to prevent the rise of temperature so as not to 

 give rots the conditions most favourable for their development. 



Out of the five different kinds of rots which have up to this time 

 been discovered in the Bombay potatoes two deserve special attention 

 in connection with this storage. The bacterial rot which is the more 

 important of the two is universally found ia practically all potato-growing 

 tracts of Bombay. The next, though a less important one, is the dry 

 Fusarium rot. If these two rots are present in any degree in the har- 

 vested potatoes the presence of the larvsB of the moth increases the rate 

 of rotting, affording as they do the ready means by which the SjDores of 

 the two rots effect an entrance into the otherwise healthy potatoes. 

 The larger the number of generations the moth passes through in a 

 potato godown the greater the danger to the heaps. These rots are 

 known to be saprophytic in nature and the infection is carried from the 

 soil along with the harvested potatoes. Any form of external injury 

 either by the larvae or by other mechanical injuries sustained by the 

 potatoes in their handling during their harvest or subsequent to harvest, 

 exposes the tubers to infection. To control the rots, which are therefore 

 the primary causes of destruction, the moth must first be prevented 

 fi'om breeding in the potatoes intended for storage. 



It is also true that under the conditions obtaining in the present 

 methods of storage in heaps, very often as deep as 3| feet, the moisture 

 given up by the potatoes in the natural process of drying coupled with 

 the high temperature particularly at the bottoms of the heaps favours 

 the spread of the bacterial rot and to a less extent of Fusarium rot. 

 If the temperature of the room rises to 86°F. or anything above this, 

 the destruction of the heaps is only a matter of days and not of weeks. 



The preservation of the potatoes means therefore the control of the 

 following four factors : — 



(1) Thorough fumigation to kill the moth larvae. 



(2) Prevention of injury to the skin of the potatoes incidental to 



frequent handling. 



(3) Thorough selection before storage so as to exclude injured 



and rotting potatoes and also those which show definite 

 signs of rots. 



(4) Ventilation of the potatoes to reduce the temperature. 



1. Fumigation of the Potatoes. — It is uimecessary for the present 

 purposes of the paper to go into the detailed hfe-history of this moth. 



