THE POTATO TUBER MOTH. 



49 



On an average the results show the value of the recommendations 

 given for fighting the tuber moth by culture. 

 These may be stated as follows: 



(1) Plant as deep as practicable (5 to 6 inches). 



(2) Use ridge culture, i. e., ridge the rows (fig. 45). 



(3) Harvest as early as possible. 



(4) Harvest before the potato tops become so dry as to drive the 

 partially grown, larvae to descend and work on the tuber. 



In harvesting the tubers, several rules must be followed to keep 

 the tubers from infestation : 



(1) The sacks should Tievgr be covered with potato tops, as the 

 larvae leave these when they wilt, and enter the potatoes. 



Fig. 45.— Potato field showing careful hilling. Walker, Cal. (Original.) 



(2) The sacks should be sewed as soon as possible and hauled 

 from the field. 



(3) Potatoes should never be left in the field or exposed to the 

 moth over night. 



(4) All cull potatoes should be gathered up within two weeks and 

 either fed to stock at once or destroyed. If left in the field they are 

 a menace to the neighbors, and to the grower himself, for the follow- 

 ing crop. 



After the j)oluloos arc harvested tliey should be marketed at once, 

 unless the grower has storage facilities and is willing to take the 

 trouble; to treat the j)()tato(!S. 



\Vliil(! t hen; are g(jod reasons Cor (h'stroyiiig th(; potato vines yet 

 tiiere appear to be even het ter reasons I'of not(h)ingso. Destr'oying 

 the potato vin(-s kills all stages of the lulx'r- niotii within, but. it also 



