10 ROOT-KNOT AND ITS CONTROL. 



the majority of the field experiments being made at the last-named 

 place. In addition to this, trips were made to the various parts of 

 the country where the disease occurs or was suspected to occur. 

 The caring for the experimental plats at Monetta, as well as the 

 making of many of the observations on these experiments, was 

 performed by ^Ir. J. M. Johnson, without whose services much of 

 the ^^Titer's work would have been impossible. At Miami the 

 cooperation of Mr. P. J. Wester, at that time gardener of the Sub- 

 tropical Laboratory and Garden, was also of considerable assistance, 

 although the experiments there were not on so large a scale as at 

 Monetta. 



PLANTS AFFECTED BY ROOT-KNOT. 



The nematode causing root-knot seems to be one of the most 

 omnivorous kno\\Ti. Neal, in 1889, reported about 65 species of 

 plants as more or less subject to attacks by this pest. Reports by 

 other investigators in different parts of the world and extensive 

 experiments and observations by the writer have increased this 

 number to 480 species and subspecies. Of this total number the 

 writer has personally observed it on 291. The most complete list 

 hitherto is that of Dr. Kati Marcinowski,^ who lists 235 species 

 (after subtracting hosts reported under two names). Almost all of 

 the more important families of flowermg plants are present in the 

 list, as well as one gymnosperm and a fern. The plants include 

 monocotyledons and dicotyledons, herbs and woody plants, annuals 

 and perennials. Most of the garden plants are affected, as are many 

 field crops. 



The list of plants shown in Table I is sure to be largely added to as 

 investigations of this disease are carried on, and is not to be looked 

 on as being in any way final. It is tiiie that the writer has made 

 many hundred examinations of plants in badly infested soil that did 

 not take the disease, but such a list is of far less value than that of 

 plants known to be susceptible. In the list are given (1) the scientific 

 name of the plant; - (2) in parenthesis, the name under which it was 

 reported, if different from the name now used ; (3) the common English 

 name, if any; (4) the name of the person fu-st reporting it on that host; 

 (5) the date of observation; and (6) the degree of injury. Where the 

 disease is reported on the host for apparently the first time, the name 

 of the first observer is omitted, the observation having been made 

 by the writer. In all cases where the writer has seen the i)lant 



1 Marcinowski, Kati, 1909. 



2 The nomenclature followed is that used by the systematic botanists of the Bureau of Plant Industry. 

 The list was submitted to the Office of Taxonomic Investigations of that Bureau, where it was revised by 

 Mr. Homer C. Skeels. In a number of cases it would have been impossible, without seeing specimens, to 

 determine to which of several segregates of a species tlie plant listed might belong, and in that case the 

 original species name was retained, if still valid. 



217 



