38 MISC. PUBLICATION 4 6, U. S. DEPT. OF AGRICULTURE 



Scott, Lindsay, and Harrison 1939 {209) : No longer effective for control 

 rotation in San Joaquin Valley, California. [Ms. data: Builds up 

 nematode populations even in winter.] 



Whittle and Drain 1935 {263) : Listed as seldom infested or highly resistant. 

 Tennessee. 



Houndstongue, see Cynoglossum. 



Houseleek, see Sempervivum. 



Hyacinth-bean, see Dolichos. 



Iberis umbellata, common annual candytuft, purple candytuft. (C, S) 



Goff 1936 (96): Infestation to very heavy (55 plants, 2 tests); average 

 rating "lightly infested." Some of the variation "may have been due 

 to the degree of infestation of the nematodes in the soil, as there seemed 

 to be a great variation in numbers even in small areas." Florida. 

 Neal 1889 (176) : "Badly affected." Florida. 

 Watkins 1929 ($48) : Candytuft rated as "resistant." Florida. 



Ilima, see Sida. 



Ilysanthes dubia. (C) 



Bessey 1911 (16): Nematodes not abundant and no injury observed. 

 Ipomoea batatas, sweetpotato. (M, N, S) 



Bessey 1911 (16): -Nematodes abundant, injury apparently not great. 



Christie, J. R. (Division of Nematology, Bureau of Plant Industry. 1939) : 

 Galls inconspicuous- even on heavily infested roots; little above-ground 

 indication of infested areas (Var. Nancy Hall). Virginia. 



Elliott 1918 (57) : An unusual instance of severe injury. Arkansas. 



Fajardo and Palo 1933 (60): Infestation moderate. Philippine Islands. 



Georgia Coastal Plain Experiment Station 1935 (81) : Unsafe for a 

 control rotation. 



Harter and Weimer 1929 (105) : The greatest loss is not to the sweetpotato 

 itself but to susceptible crops that follow. 



Milbrath 1923 (162): Susceptible; suggested for indicator plant. Cali- 

 fornia. 



Pittman 1929 (192) : Not usually attacked to such an extent as other market- 

 garden plants. Western Australia. 



Poole 1933: 58 Has been an important means of dissemination. North 

 Carolina. 



and Schmidt 1929 (195) : Yields small if attacked early; plants not 



killed; even the most resistant varieties would increase the soil 

 infestation. North Carolina. 



Taubenhaus and Ezekiel 1933 (226) : Infested occasionally, little loss. 

 Texas. 



United States Bureau of Plant Industry 1926: 59 Infestation said to be 

 often serious in Arkansas. 



Watson and Goff 1937 (258): Rather tolerant; rated as No. 29 in order of 

 susceptibility [from okra, No. 1, to corn, No. 46]. Florida. 



Zimmerley and Spencer 1923 (267) : Listed as "practically immune." 

 Virginia. [Question: What variety?] 



The following reports, which analyze varietal differences in susceptibility, are 

 more significant than the preceding, which judge all sweetpotatoes alike, or gen- 

 eralize a limited experience without reporting the variety. To balance the reports 

 on resistant varieties it should be remembered that the same authors report severe 

 infestations on many varieties, especially on Nancy Hall (195, 261, 268), Red 

 Bermuda (195), and Red Brazil (195, 261). The susceptible variety Southern 

 Queen is listed below because of conflicting reports. 



Var. Big-Stem Jersey. 



Poole and Schmidt 1929 (195): Resistant; slight infestation in roots, some- 

 times also in potatoes (1.2 percent; 2 seasons). North Carolina. 



Weimer and Harter 1925 (261): Highly resistant, not immune; a few galls 

 seen in two of the three tests (1 season). California. 



Whittle and Drain 1935 (263) : Listed as seldom infested or highly resistant. 



$ Wood, Jessie I., Stevens, Neil E., and Miller, Pal t l R. diseases of plants in the united states 

 in 1932. U. S. Bur. Plant Indus., Plant Dis. Rptr. Sup. 85, pp. 1-82. 1933. [Mimeographed.] See report 

 by R. F. Poole, Root Knot in North Carolina in 1932, p. 22. 



59 See p. 56 of reference given in footnote 23, p. 19. 



