Nematode Root Parasite — LINFORD, et al. 
117 
chambers sometimes slit the elongating root, 
and paratylenchs enter freely. Cracks in the sur- 
face of enlarging galls caused by Heterodera 
marioni have been seen to serve in the same 
way. Entry into epidermal and cortical cells 
sometimes occurs through penetration wounds 
made by two species of nematodes consistently 
present in the soil used in these studies, Rotylen- 
chulus reniformis Linford and Oliveira (1940) 
and a transient rotylench formerly reported from 
this laboratory as Rotylenchus multicinctus . 
Both species perforate cortical cells as they 
penetrate somewhat radially to the stele. They 
sometimes break into an epidermal cell and 
then move on to another location before pene- 
trating more deeply; and the transient rotylench 
may penetrate deeply, then withdraw, and move 
to another site. That some of these wounds are 
utilized was clear when as many as three para- 
tylenchs were found entering at the side of a 
single larger form. Many and perhaps most of 
the paratylenchs found within the epidermis 
and cortex appear to have entered through one 
or another of these types of wounds. 
HOST RANGE 
During investigations of feeding habits it 
became apparent that Raratylen clous minutus is 
able to feed upon roots of a wide range of 
plants because the feeding process was observed 
on every plant species that was subjected to ade- 
quate observation. No attempt to determine the 
limits of the host range therefore seemed worth- 
while. A few additional species of weeds, crop 
plants, and ornamentals were grown in minia- 
ture root-observation boxes of infested soil and, 
as before, feeding was observed on all of them 
that developed sufficient healthy roots in a 
position suitable for observation. Roots of a 
few species were stained and cleared and, in 
some of them, eggs were found associated with 
females within the cortex. These plants are 
marked with an asterisk in the list that follows. 
Plainly this nematode is able to obtain from 
these plants and also from pineapple plants suf- 
ficient nutrient to reproduce. The conditions of 
these observations are such, however, that it 
would be misleading to list plants so examined 
in which eggs were not found, for the plants 
were all young, numbers of nematodes within 
the roots were few, and, judging especially from 
the pineapple, which was studied in more detail 
than other hosts, most of the eggs are laid free 
in the soil or on the root surface. 
Ananas comosus (L.) Merr. : Pineapple 
Avena sativa L. : Oat, Vicland 
Bidens pilosa L.: Spanish needle 
Brassica oleracea L. var. capitata L.: Cabbage, 
Golden Acre 
Cucumis sativus L. : Cucumber, Long Green 
Cucurbita Pepo L. : Squash, White Bush 
* Emilia sonchifolia (L.) DC.: Flora’s paintbrush 
*Eschscholzia calif ornica Cham.: California poppy 
Euphorbia geniculata Ortega 
Polygonum Fagopyrum- L.: Buckwheat 
Helianthus annum L. : Sunflower, Mammoth Rus- 
sian 
Hibiscus esculentus L. : Okra, Tall Green 
Medicago sativa L. : Alfalfa, Chilean 
Oxalis corniculata L. var. viscidula Wieg. : Sticky 
sorrel 
Portulaca oleracea L.: Purslane 
*Phaseolus aureus Roxb.: Mung bean 
Phaseolus lathyroides L.: Wild pea-bean 
Raphanus sativus L. : Radish, Scarlet Globe 
Richardia brasiliensis (Moq.) Gomez: Richard- 
sonia, false ipecac 
Tagetes erecta L.: Marigold, Guinea Gold 
Rricholaena repens (Willd.) Hitchc. : Natal grass 
*Triticum aestivum L. : Wheat, Henry 
Vigna sinensis (L.) Savi: Co wpea, Whippoorwill 
Zea Mays L. : Corn, maize 
* Zinnia elegans Jacq. : Zinnia, Cut-and-Come- 
Again 
DISCUSSION 
The lack of visible pathology in cells fed 
upon, and the occurrence of large populations 
upon roots of apparently normal pineapple 
plants, tend to indicate that this paratylench is 
non-pathogenic. Such a conclusion would be 
premature with present evidence. All observa- 
tions reported here have been of relatively short 
duration, and experimental tests of pathogen- 
icity can be made only after pure cultures of 
this species have been developed, free from 
other nematodes and root-invading fungi that 
have been associated with it in these studies. 
