ROOT KNOT NEMATODE INFESTATION 11 



Watson, Goff, and Bratley 1937 (259): Most weeds were found to be 



infested but none heavily. Florida. 

 Whittle and Drain 1935 (263): Practically all weeds and wild grasses are 



susceptible. Tennessee (?). 



Generalizations on "weeds" are practically meaningless in an analysis of root 

 Knot problems. The weed flora varies widely in different regions, and plants 

 that are weeds in some places may even be cultivated in others. Certain weeds 

 have been found useful in nematode-control rotations, as shown above; yet the 

 fact remains that weeds are very often a means of increasing soil infestation, 

 and that the control of weeds is an essential part of all sanitation measures for 

 root knot control. 



PLANT SPECIES AND VARIETIES REPORTED RESISTANT 



OR TOLERANT 



Abrus precatorius, paternoster-bean, rosary-pea. (C) 



Beeley 1939 (14)'- Found attacked, but somewhat "resistant." Malaya (?). 

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



Acanthospermum australe (A. xanthoides) . (C) 



Godfrey 1935: 10 Infestation commonly observed to be light. Hawaii. 



Acokanthera (Toxicophlaea) sp. (C) 



Grower: Not injured. California. 



Agapanthus umbellatus, agapanthus. (C, N) 



Grower: Infestation evident on only a few plants; not particularly trouble- 

 some. Florida. 



Agave americana, centuryplant. (C) 



Growers: Vigorous; not injured by infestation. California. [Such state- 

 ments, from two different growers, do not clearly constitute a host 

 record; there are no other reports on this plant.] 



Ageratum conyzoides. (C) 



Bally and Reydon 1931 (8): Frequently infested; galls found on dead roots. 



Java. 

 Barber 1901 (9) : "Very severely attacked, although it did not seem much 



the worse for it." India (Madras). 

 Breda de Haan 1899 (24) : More galls than on other weeds. Sumatra. 

 Fajardo and Palo 1933 (60): Rated as "resistant" (judged by growth); 



five plants, all infested. Philippine Islands. 

 Linford 1939 (142): Green stem tissue attracted larvae in vitro, though 



somewhat more slowly than did other highly attractive tissues. Hawaii. 



Infestations have been reported also from Belgian Congo (86), China (138), 

 Nyasaland (214), and Tanganyika (269). 



Ageratum sp. 



Goff 1936 (96): No infestation found (25 plants, 1 test). Florida. 

 Watkins 1929 (248): Seriously injured (annual ornamental). Florida. 

 Zimmermann 1900 (268): Heavily infested weed in coffee plantations. Java. 



Agropyron repens (Triticum re-pens), couchgrass, quackgrass. (C) 



Apparently all citations of this plant as a host of H. marioni refer to Greeff 

 (101), and Greeff probably had a different nematode (see Goodey, 99). 



Agrostis alba, "herdsgrass," redtop. (C) 



Bessey 1911 (16): No infestation found. 



Godfrey 1928 (92): No infestation found on redtop (one test). Hawaii. 



Shaw 1940 (213a): Tobacco in enclosure units showed no severe infestation 

 following 2 years' bare fallow, 8.3 percent following 2 years' herdsgrass 

 (redtop), and 100 percent following 2 years' tobacco. [North Carolina.] 



Whittle and Drain 1935 (263): Redtop listed as seldom infested or highly 

 resistant. Tennessee (?). 



i° Godfrey, G. H. hitherto unreported hosts of the root-knot nematode. U. S. But. Plant 

 Indus., Plant Dis. Rptr. 19: [29]-31. 1935. [Mimeographed.] 



