B. P. I.-72f|. 



THE NEMATODE GALLWORM ON POTATOES AND 

 OTHER CROP PLANTS IN NEVADA.' 



INTRODUCTION. 



During the seasons of 1910 and 1911 there occurred in certain irri- 

 gated ])otato-growing (Ustricts of Nevada an outbreak of a ])otato 

 disease known locally as the eelworm. Particular attention was 

 attracted to the ravages of this disease because several carloads of 

 potatoes shipped from Nevada into California during the winter of 

 1910-11 were condemned by certain county horticultural commis- 

 sioners of California and were returned to Nevada to be disposed of 

 elsewhere. A recurrence of the disease in the season of 1911 and the 

 sliipment of infected potatoes into California resulted in the issuance 

 l)y the State Commissioner of Horticulture of California of an order 

 establishing a quarantine against all potatoes shipped into that State 

 from the counties of Lyon, Churchill, and Washoe, in the State of 

 Nevada.^ 



Since California markets have afforded the chief outlet for the 

 potatoes grown in Nevada in excess of local needs and since pota- 

 toes have been a very profital)lo crop in certain irrigated districts 

 in Nevada, the closing of California markets to their potatoes has 

 been severely felt by Nevada potato growers. The outbreak of 

 the so-called eelworm disease or nematode gallworm disease in 

 these Nevada potato fields has been so severe and the results so 

 disastrous as to warrant bringing together the available information 

 concerning this disease as it affects potatoes and other crop plants, 

 for the assistance of the affected districts in Nevada. Some of this 

 information may be applicable also to other sections of the country, 



' Owing 1o a severe outbreak of a potato disease in certain irrigated districts in Nevada, caused by the 

 nematode Helerodera radicicola, there has been an urgent demand for information as to the cause of the 

 disease, the probable extent of its spread, and the possible remedies. In order to meet this demand for infor- 

 mation a committee was appointed, consisting of Dr. N. A. Cobb, Technologist, Prof. L. C. Corbett, Horti- 

 culturist, r<r. W. A. Orton, Pathologist, and Mr. C. S. Scofield, Agriculturist, all of the Bureau of Plant 

 Industry, to bring together such available information as would be most useful to the potato growers and 

 others concerned. While the present interest in this nematode is due to its attacks on potatoes, it should 

 be clearly imderstood (1) that the same nematode is parasitic on many other important crop plants, where 

 it may cause damage, and (2) that this is but one of a number of species of parasitic nematodes. It is 

 important to keep these facts in mind to avoid serious mistakes in dealing with the present problem m 

 Ne\-ada and similar problems that may occur elsewhere. — B. T. Galloway, Clticf of Bureau. 



* For further details in rcfen^ncc to this quarantine order, see Monthly Bulletin of the State Commissioner 

 of Horticulture of California, vol. 1, December, 1911, pp. 26-30; and also the same publication for January, 

 1912, in which a modification of this order was published. 



29196°— Cir. 91 12 3 



