14 NEMATODE GALLWOEM ON POTATOES, ETC., IN NEVADA. 



worm, and garbage 

 containing peelings 

 of diseased potatoes 

 is also a prolific 

 source of infestation. 

 The use as seed 

 of any infected 

 potatoes is to be 

 strongly condemned. 

 No effort should be 

 spared to locate all 

 infested fields in a 

 district where the 

 nematode is known 

 to occur, and seed 

 potatoes should be 

 secured from fields 

 known to be unin- 



ease are to be found in the fested or, better still, 

 root enlargements. (After „ . ■, 



3. c. Neai.) fi'om a rcgiou where. 



Fig. 19.— Roots of okra, show- 

 ing the enlargements caused 

 by the gallworm. The nem- 

 atodes producing this dis- 



Fig. 20.— Roots of cucumber, showing en- 

 largements caused by the gallworm. 

 Nearly all other common garden plants 

 are similarly attacked. There are many 

 thousands of the worms in the nodules 

 upon such a root system. (After Kati 

 MarcLnowski. ) 



because of adverse climatic 

 conditions, the nematode 

 is unknown. 



A thorough inspection 

 should be made of all fields 

 in each district where the 

 nematode is suspected to 

 occur, and all infested fields 

 should be devoted to crops 

 which the nematode does not attack. There are 

 many plants besides the potato which are susceptible 

 to nematode injurj^, and these should never be 

 planted or allowed to grow in fields where the gall- 

 worm is found. There are a number of crops that are 

 not attacked by this parasite, and these only should 



Fig. 21. — Roots of lettuce, showing 

 enlargements caused by the gall- 

 worm. Many plants are killed 

 in the seedling stage liy the 

 gallworm. (After Kati Mar- 

 cinowski.) 



fCir. 91] 



