CIRCULAR No. 162. Issued December 4, 1912. 
United States Department of Agriculture, 
BUREAU OF ENTOMOLOGY. 
L. O. HOWARD, Entomologist and Chief of Bureau. 
THE POTATO-TUBER MOTH.! 
(Phthorimzxa operculella Zell.) 
3y F. H. Currrenpen, Sc. D., 
In Charge of Truck Crop and Stored Product Insect Investigations. 
INTRODUCTORY. 
For many years the potato-tuber moth, known scientifically as 
Phthorumea operculella Zell., has been the worst potato pest in 
California. It has now reached the State 
of Washington and menaces adjacent 
States. This insect feeds also upon to- 
mato, 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 
band c; and the pupa in d._ Sizes are in- 
dicated by the size lines in the figure. 
The eggs may be laid upon the leaves or 6. 1—The potato-tuber moth (Phtho- 
on other parts of the plants, and the mi- 172s opereuleilt): @, Moths 0, larva, 
2 : ateral view; c, larva, dorsal view; d, 
nute caterpillars or worms quickly bore pupa; ¢, , segments of larva en- 
between the surfaces of the leaves or into eee nore ea 
the potato skin, which they mine in every 
direction, finally devouring the exterior. It is believed that there 
are two or more generations in the course of a summer, and certainly 
another one can be produced in store. It thus happens that 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. Ataisasection showing the eges at the top; at b, a badly infested 
Bae 
gN 
—. 
1 The account here given is preliminary in character and issued with the purpose of warning ‘potato 
| growers and giving general information in regard to remedies. Work has begun on this species and will 
continue. 
63079°—Cir. 162—12 
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