THE POTATO TUBER MOTH. 15 



In the files of the Bureau of Entomology there are also records of 

 this species boring into the stems of poka or Cape gooseberry {Pliy- 

 salis peruviana) , made by Mr. Jacob Kotinsky in Hawaii. The species 

 has also been found mining the leaves of Physalis mollis and Solanum 

 elaeagnifolium, at Brownsville, Tex., by Messrs. McMillan and Marsh, 

 of this bureau. 



The tuber moth is unable to increase rapidly on plants which 

 confine its activities to mining the leaves, owing to the abundance 

 of its parasitic and predacious enemies. In California, therefore, 

 only the potato, tomato (figs. 13, 14), and eggplant (fig. 15) may be 

 considered as affording suitable protection to the larvae, and of these, 

 the potato only is of primary importance. While adults have been 

 reared from tomato and eggplant fruit, no important infestations 

 have been noted under field conditions, even where moths were 

 abundant and close at hand. 



LIFE HISTORY AND HABITS. 



THE EGG. 



The egg, under outdoor conditions, is deposited early in the spring 

 on the underside of the foliage of j^oung potato plants. Sometimes 

 the eggs are placed on the stems or petioles of the leaves, but more often 

 the body of the leaf is selected. In such cases the eggs are placed 

 singly, though two or more may be quite close together. Three is 

 the largest number that has been noted on a single leaf in the field. 



In bins, or in stacks of potatoes, oviposition takes place through- 

 out the winter, but is most general during the warmer months. 

 The eggs are usually deposited in the eye or a rough scar on the potato, 

 and when placed in this way are generally grouped, as many as 30 

 having been found in one eye. In sprouting potatoes the eggs are 

 often placed in circles around the base of the sprout. In this way 

 they are protected on aU but one side. 



Another favorite place for oviposition is at the point of scab in- 

 jury, and the narrow deep cracks caused in this way are very often 

 filled with the eggs of the tuber moth. Here also they are pro- 

 tected. Where the eggs occur in more or less of a mass, scales from 

 the wings and body of the moth are thinly scattered over them. 

 This probably is not due to an effort of the moth to hide the eggs, but 

 is the result of her moving about during the deposition of the egg 

 mass. 



In potato bins eggs are often found on the sacks, in depressions 

 on the sprouts, and on debris occurring on or between the potatoes. 

 However, very small num>)crs of eggs are found deposited in such 

 places, and they g(!nerally 0(;cur singly. 



The eggs arc usually deposited during the evening, night, or early 

 morning, although in cool weather and in darkened bins oviposition 



