ELISHA MITCHELL SCIENTIFIC SOCIETY. 81 



NEMATODE ROOT-GALLS. 



A PRELIMINARY REPORT ON THE LIFE HISTORY AND METAMORPHOSES OF A 

 ROOT-GALL NEMATODE, HETERODERA RADICICOLA (gREEFF) MULL., AND 

 THE INJURIES PRODUCED BY IT UPON THE ROOTS OF VARIOUS PLANTS.* 



BY GEO. F. ATKINSON. 



I. 



INTKODUCTORY. 



The purpose of the present paper is to put in the form of a 

 preliminary report the result of some investigations made this 

 autumn, in the neighborhood of the Experiment Station, upon 

 the nature and cause of the abnormal growths found upon the 

 roots of various plants. These deformities are popularly termed 

 '^ root- knot." Soon after entering upon my new field of labor 

 here my attention was called to the sul)ject by the Director, 

 Prof. J. S. Newman, who showed me tomato plants the roots of 

 which were exceptionally ''knotty." 



The investigations were begun the first of October, 1889, and 

 continued for about six weeks, when the subject-matter of this 

 preliminary report was sent to the press. 



At the time the work was undertaken I was unaware that a 

 Bulletin was being published by the Division of Entomology, 

 U. S. Agricultural Department, under the direction of Dr. C. V. 

 Riley, embodying the results of investigations made by Dr. J. 

 C. Neal, of the Florida Experiment Station. The first notice I 

 had of this work was from Insect Life.'f 



That workj has since been distributed, and has reached me 

 just about the time of going to press. Unfortunately there are 

 many errors in the part dealing with the structure and life his- 



Scienee Contributions, Ala. Polytechnic Inst., Vol. I, No. 1, Auburn, Ala., Dec, 1889. 



tVol. II, No. 3, Washington, 1889. 



JBulletin No. 20, Division of Entomology, U. S. Dept. of Agr. The Root-knot Disease 

 of the Peach, Orange and other Plants in Florida, Washington, 1889. 



