on 
go. ae (8 i AGRICULTURE 
Contribution from the Bureau of Entomology, L. O. Howard, Chief. 
October 2, 1913. 
THE POTATO-TUBER MOTH.’ 
By F. H. Cuirrenpen, Sc. D., 
In Charge of Truck Crop and Stored Product Insect Investigations. 
INTRODUCTORY. 
For many years the potato-tuber moth, known scientifically as 
Phthorimea operculella Zell., has been the worst potato pest in 
California. It has now reached the State of Washington and southern 
Texas and menaces adjacent States. This insect feeds also upon 
tomato, eggplant, and tobacco, which do not, however, as a rule, 
suffer much injury. When it occurs on 
tobacco it is known as the splitworm. 
The mature moth of this species, which 
is quite small ‘and grayish in color, is 
shown in figure 1, a; the larva is shown 
in 6 and c; and the pupaind. Sizes are 
indicated by the size lines in the figure. 
The eggs may be laid upon the leaves 
or on other parts of the plants, and the 
minute caterpillars or worms quickly 
bore between the surfaces of the leaves 
or into the potato skin, which they mine 
in every direction, finally devouring the Be ee ee ee 
exterior. It is believed that there are _ ;simza operculelia): a, Moth; 6, larva, 
Gwo.or more generations in the course of ‘tl view; ¢, larva, dors) view; 
: , pupa; e, f, segments of larva, en- 
a summer, and certainly another one can __larged. (Redrawn from Riley and 
be producedinstore. Itthushappensthat 4°"? 
this insect belongs to both truck-crop and stored-product insect pests. 
An example of injury by this species to potatoes is shown in figure 
2. At ais a section showing the eggs; at the left is a section of a 
badly infested potato containing two pits, d and f, in which the 
larva has been at work, while at 6 and ¢ is shown the egg, highly 
magnified. Figure 3 gives an exterior view of a potato which has 
been destroyed by the tuber moth. 
1 The account here given is issued with the purpose of warning potato growers and giving general infor- 
Mation in regard to remedies. Work was begun on this species in 1912 and will continue. This is a 
revised and amplified account, first published as Circular 162 of the Bureau of Entomology. 
8365°—13 
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