THE POTATO TUBER MOTH. 51 



QUARANTINE. 



Quarantine as a method of keeping out the tuber moth has 

 attracted considerable attention" in the Western States in recent 

 years. A quarantine of one district against another when the 

 tuber moth is estabhshed in both places is of little value, as the 

 numbers of this insect in any one year are not influenced as greatly 

 by its numbers the preceding year, or by any that might be introduced, 

 as by food and chmatic conditions. The great interstate shipment of 

 potatoes throughout the West proves that the potato question is a 

 factor which affects many of the people living in those States, and 

 a hasty or ill-advised quarantine might cause losses which would 

 more than offset any advantages to be gained from it. 



In conclusion it should be said that while the tuber moth is always 

 a menace in warmer climates, it is by no means a fatal potato pest, 

 and its damage, if not totally ehminated, can at least be minimized 

 by rational farming methods and a knowledge of the habits of the 

 insect. For this reason whenever there has been an outbreak of the 

 moth in a new district the conditions ^ in this district should be studied 

 and means devised to prevent a recurrence of injury. 



SUMMARY. 



(1) The tuber moth injures the potato by destroying the leaf 

 surface and tunneling in the substance of the tuber. 



(2) Its life history is variable, but in southern California all the 

 stages exist at aU times of the year. 



(8) Tlie numbers of the insect should be reduced by practicing 

 good farming and leaving no tubers exposed for the insect to work on. 



(4) Potatoes should be harvested and marketed as rapidly as possi- 

 ble, unless the grower has facilities for storage and is prepared to 

 treat the potatoes if necessary. 



(0) Once the tubers become infested the best way of ending the 

 damage is to fumigate with carbon bisulphid, using 2 pounds to 1,000 

 cubic feet of air space (measured before storing the tubers) and allow- 

 ing 48 hours for fumigation. 



(6) Clean or unuifcsted potatoes should be kept away from the 

 moth. 



(1) Potatoes should never be left in the ground after they are 

 ripe and where the soil is dry. 



(8) When tubers are infested and facilities are lacking for storing 

 in bins, the progress of infestation can be checked by holding the 

 ])otuloes in cold storage;. TIk; temperature shoidd ho, about 'M° to 

 40^ V. This should Ix; adopted only as a temf)orary method in 

 keeping potiilo(;s from (h'terioraf ing in vahie wliile th(\y ai'(; being held 

 ff)r a rise in price. 



> This refers especially to various methods of storing potatoes. 



