6 NEMATODE GALLWORM ON. POTATOES, ETC., IN NEVADA. 
roots and bore their way into the plant tissues by means of a spear- 
like structure, which is protruded from the mouth. They feed upon . 
the cell sap of the host plants. 
After fertilization takes place the females begin tontotluteen by 
forming eggs within the body. These eggs are laid at the rate of 
from 10 to 15 a day, and it is estimated that one female may lay as 
many as 500 eggs. After completing the egg-laying process the female 
dies, the male having died 
seon after fertilizing the 
female. 
The worm lives from one 
season to the next, either in 
the egg stage or in the larval 
stage within the host plant. 
The hfe of the individual 
worm is short (only a few 
weeks), when temperature 
and moisture conditions are 
such as to favor growth.1 
It is possible, therefore, to 
oreatly reduce the numbers, 
if not to exterminate the 
worm entirely, by keeping 
the infested land free from 
plants upon which the worm 
can feed. 
Fia. 3.—Potato infected with the gallworm. This shows SOURCES OF INFESTATION. 
the rough character of the surface, which indicates the 
presence of these worms. The knobs, or warts, are often ll : é 
much more strongly developed thanin the above. Gaill- The galiworm discussed in 
worms in seed potatoes are particularly dangerous, for if this paper is one of a larce 
infected potatoes are used for seed the land will be inocu- f é f mi 
lated. If infected potatoes are used as food, the refuse number oO species or nema- 
parts should be cooked or destroyed. Otherwise they tode worms. This p articu- 
may spread the disease. (After F. B. Headley.) 2 
lar species occurs very gen- 
erally throughout the southern United States. In many sections 
is found in such large numbers as to be a serious pest to many crop 
plants, such as the peach, the fig, cowpeas, cotton, and many vege- 
tables. It may be transported from place to jeilsres on any of these 
plants which it infests or in soil from infested fields. Probably the 
most common method of transporting the worm is through the ship- 
ment of nursery stock and of potatoes. The distribution of the worm 
1 Additional information concerning the life history of this parasite, with a list of susceptible plants and 
details of experiments in controlling the nematode in the southeastern United States, may be found in 
Bulletin 217 of the Bureau of Plant Industry, entitled ‘‘Root-Knot and Its Control,” by Dr. Ernst A- 
Bessey, issued November 21, 1911. 
- [Ciradt| 
