NEMATODE GALLWORM ON POTATOES, ETC., IN NEVADA. {i 
from field to field in any particular district may be accomplished by 
carrying soil on agricultural implements, on the feet of animals or 
men, or by transplanting plants from one field to another. In fact, 
there are so many ways in which infestation can be accomplished 
that the greatest precautions should be used to prevent the distribu- 
tion of infested earth or plants into uninfested areas. The careless 
disposal of garbage containing infected potato peelings or the spread- 
ing of manure from yards where infected roots or tubers have been 
used as stock feed may transport the worm and develop serious 
infestation. 
Z Hs 
() 
Fic. 4.—Microphotograph of the eggs of the gallworm and the young 
worms just hatched, taken from a potato. This appearance is often 
seen in microscopic preparations made from infested areas of roots. 
(After F. B. Headley.) 
All classes of nursery stock, including strawberry plants, tomato 
plants, and small fruits, should be examined with great care if they 
are to be set in fields which it is desired to keep free from this parasite. 
UNINFECTED SEED POTATOES ABSOLUTELY ESSENTIAL. 
In attempting to control this disease it is, of course, absolutely 
essential to plant uninfected potatoes as seed. It is not enough to 
be sure that the potatoes planted do not show superficial evidences 
of the disease; it should be determined beyond doubt that there is 
absolutely no infection present. This can best be assured by securing 
[Cir. 91] 
